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Table of Contents 1. Introduction 2. Graphics 3. Typography 4. Digital Images and Editing 5. Computer Graphics 6. Rendering 7. 3D Computer Graphics 8. Computer-Generated Imagery 9. Special Effect 10. Motion Capture 11. Rotoscope 12. Computer Representation of Surfaces 13. 2D Computer Graphics 14. Shading 15. Rasterisation 16. Raster Graphics and Vector Graphics 17. Adobe Photoshop 18. Macromedia Dreamweaver, Fireworks and QuarkXPress 19. Adobe Flash
Graphic design
Saul Bass's poster for the film, The Man with the Golden Arm - a highly regarded work of graphic design. The film was also notable for its groundbreaking title sequence, also by Bass. Graphic design is a form of communication using text and/or images to present information. The art of graphic design embraces a range of mental skills and crafts including typography, image development and page layout. Graphic design is applied in communication design and fine art. Like many forms of communication, graphic design often refers to both the process (designing) by which the communication is created, and the products (designs) such as creative solutions, imagery and multimedia compositions. The designs are applied to static media as well as electronic media, not always in the completed form. In commercial art, client edits, technical preparation and mass production are usually required, but usually not considered to be within the scope of graphic design. Although the term 'graphic designer' was first coined in the 20th century, the story of graphic design spans the history of marks of humankind from the magic of the caves of Lascaux to the dazzling neons of Ginza. In both this lengthy history and in the relatively recent explosion of imaging in the 20th and 21st centuries, there is sometimes a blurring distinction and over-lapping of advertising art, graphic design and fine art. After all, they share the same elements, theories, principles, practices and languages, and sometimes the same benefactor or client. In advertising art the ultimate objective is the sale of goods and services. In graphic design, "the essence is to give order to information, form to ideas,
expression and feeling to artifacts that document human experience." "Fine art refers to arts that are 'concerned with beauty'..."
Principles and elements of design Design elements are the basic tools in every design discipline. The elements (including shape, form, texture, line, value, and color) compose the basic vocabulary of visual design. Design principles, such as balance, rhythm, emphasis, and unity, constitute the broader structural aspects of the composition.
Graphic design theory According to the classic theory of design, or graphic design, visual design, art, the visual excitement of a work of design is a result of how the composition of the design elements create mood, style, message, and a look. There is research and planning that is needed for most design work: •
•
•
the design process, which encompasses the step-by-step and often complex path that a designer takes toward a design solution through research, exploration, reevaluation, and revision of a design problem. This process starts with the client and ends with the finished design product. use of a grid to help improve or speed up the layout of images and text. Like the steel internal frame of building, the grid helps the 2D designer place information on paper or screen in a way that improves the design visually and its usability. impact and use of technology for design solutions. Graphic designers are usually first to adopt and incorporate new technology in solutions or concepts when possible. This experimentation is not always to the benefit of the design or the user.
The classic theory of design continues to be the first one introduced to starting students and amateurs, with details such as the number of principles varying from book to book and instructor to instructor. However, the classic theory of design is limited in scope as it only considers the decorative aspects of design. More comprehensive theories and treatments include or emphasize aspects of visual communication and usability, sometimes referring to sociology and linguistics.
Graphic design history
The paintings in the caves of Lascaux around 14,000 BC and the birth of written language in the third or fourth millennium BC are both significant milestones in the history of graphic design and other fields which hold roots to graphic design. The Book of Kells is a very beautiful and very early example of graphic design. The Book is a lavishly decorated hand-written copy of the Gospels of the Christian Bible created by Celtic monks around 800AD. Johann Gutenberg's introduction of movable type in Europe made books widely available. The earliest books produced by Gutenberg's press and others of the era are known as( Incunabula). The Venetian printer and publisher Aldus Manutius developed a design style and structure for the book that remains largely intact to the present day. Graphic design of this era is sometimes called either Old Style (after the Gothic and handwriting-based typefaces which the earliest typographers used), or Humanist, after the new typefaces imitating the lettering in Roman carved inscriptions. These were introduced as part of the revival of classical learning, and still form the basis of the most commonly used Western typefaces. Graphic design after Gutenberg saw a gradual evolution rather than any significant change. In the late 19th century, especially in the United Kingdom, an effort was made to create a firm division between the fine arts and the applied arts. From 1891 to 1896 William Morris' Kelmscott Press published books that are some of the most significant of the graphic design products of the Arts and Crafts movement, and
made a very lucrative business of creating books of great stylistic refinement and selling them to the wealthy for a premium. Morris proved that a market existed for works of graphic design and helped pioneer the separation of design from production and from fine art. The work of the Kelmscott Press is characterized by its obsession with historical styles. This historicism was, however, important as it amounted to the first significant reaction to the stale state of nineteenth-century graphic design. Morris' work, along with the rest of the Private Press movement, directly influenced Art Nouveau and is indirectly responsible for developments in early twentieth century graphic design in general. Piet Mondrian, born in 1872, was a painter whose work was influential in modern graphic design. Although he was not a graphic designer his use of grids inspired the basic structure of the modern advertising layout known also as the grid system, used commonly today by graphic designers.
20th century
Famous SS Normandie poster by Adolphe Muron Cassandre
I Love New York campaign by Milton Glaser
Modern design of the early 20th century, much like the fine art of the same period, was a reaction against the decadence of typography and design of the late 19th century. The hallmark of early modern typography is the sans-serif typeface. Early Modern, not to be confused with the modern era of the 18th and 19th centuries, typographers such as Edward Johnston and Eric Gill after him were inspired by vernacular and industrial typography of the latter nineteenth century. The signage in the London Underground is a classic of this era and used a font designed by Edward Johnston in 1916. In the 1920s, Soviet Constructivism (art) applied 'intellectual production' in different spheres of production. The movement saw individualistic art as useless in revolutionary Russia and thus moved towards creating objects for utilitary purposes. They designed buildings, theater sets, posters, fabrics, clothing, furniture, logos, menus etc. Jan Tschichold codified the principles of modern typography in his 1928 book, New Typography. He later repudiated the philosophy he espoused in this book as being fascistic, but it remained very influential. Tschichold, Bauhaus typographers such as Herbert Bayer and Laszlo Moholy-Nagy, and El Lissitzky are the fathers of graphic design as we know it today. They pioneered production techniques and stylistic devices used throughout the twentieth century. Although the computer has altered production forever, the experimental approach to design they pioneered has become more relevant than ever. The following years saw graphic design in the modern style gain widespread acceptance and application. A booming post-World War II American economy established a greater need for graphic design, mainly advertising and packaging. The emigration of the German Bauhaus school of design to Chicago in 1937 brought a "mass-produced" minimalism to America; sparking a wild fire of "modern" architecture and design. Notable names in mid-century modern design include Adrian Frutiger, designer of the typefaces Univers and Frutiger; Paul Rand, who, from the late 1930's until his death in 1996, took the principles of the Bauhaus and applied them to popular advertising and logo design, helping to create a uniquely American approach to European minimalism while becoming one of the principal pioneers of the subset of graphic design known as corporate identity; and Josef Müller-Brockmann, who designed posters in a severe yet accessible manner typical of the 1950s and 1960s.
The reaction to the increasing severity of graphic design was slow but inexorable. The origins of postmodern typography can be traced back as far as the humanist movement of the 1950s. Notable among this group is Hermann Zapf who designed two typefaces that remain ubiquitous — Palatino (1948) and Optima (1952). By blurring the line between serif and sans-serif typefaces and re-introducing organic lines into typography these designs did more to ratify modernism than they did to rebel. An important point was reached in graphic design with the publishing of the First things first 1964 Manifesto which was a call to a more radical form of graphic design and criticized the ideas of value-free design. This was massively influential on a generation of new graphic designers and contributed to the founding of publications such as Emigre magazine. Saul Bass designed many motion picture title sequences which feature new and innovative methods of production and startling graphic design to attempt to tell some of the story in the first few minutes. He may be best known for his work for Otto Preminger's The Man with the Golden Arm (1955). Milton Glaser designed the unmistakable I Love NY ad campaign (1973) and a famous Bob Dylan poster (1968). Glaser took stylistic hints from popular culture from the 1960s and 1970s. David Carson has gone against the restrictiveness of modern designs. Some of his designs for Raygun magazine are intentionally illegible, featuring typography designed to be visual rather than literary experiences.
Use of computers
An example of Adobe Photoshop, a tool used by most professional Graphic Designers.
In the mid 1980s, the arrival of desktop publishing and the introduction of software applications such as Adobe Illustrator and Aldus Pagemaker introduced a generation of designers to computer image manipulation and 3D image creation that had previously been unachievable. Computer graphic design enabled designers to instantly see the effects of layout or typography changes without using any ink in the process. Early on April Greiman recognized the vast potential of this new medium and quickly established herself as a pioneer of digital design. She was first known for her 1986 layout in the magazine Design Quarterly. Common graphic design software applications include Adobe InDesign, Adobe Photoshop, Adobe Illustrator, QuarkXPress, Macromedia Dreamweaver, Macromedia Fireworks and Macromedia Flash. For more details on software used by graphic designers, see art software. Computers are now considered to be an indispensable tool used in the graphic design industry. Computers and software applications are generally seen, by creative professionals, as more effective production tools than the traditional methods. However, a few designers continue to use manual and traditional tools for production, such as Milton Glaser. Computers may or may not enhance the creative process of graphic design, depending on which process best stimulates the creativity of the designer. Rapid production from the computer allows many designers to explore multiple ideas quickly with more detail than what could be achieved by traditional hand-rendering or paste-up on paper, moving the designer through the creative process more quickly. New ideas may come in the form of exploring software features that would not have been considered without the software. However, some professional designers may explore ideas on paper to avoid creating within the limits of the computer configuration, enabling them to think outside the box; the box being the computer. Some creative graphic design ideas are innitiated and developed to near completion in the mind, before either traditional methods or the computer is used. A graphic designer may also use sketches to explore multiple or complex ideas quickly without the potential distractions of technical difficulties from software malfunctions or software learning. Hand rendered comps may be used to get approval of a graphic design idea before investing what would be too much time to produce on a computer if rejected.
Thumbnail sketches or rough drafts on paper may then be used to rapidly refine and produce the idea on the computer in a hybrid process. This hybrid process is especially useful in logo design where a software learning curve may detract from a creative thought process. The traditional-design/computer-production hybrid process may be used for freeing ones creativity in page layout or image development as well. Traditional graphic designers may employ computer-savvy production artists to produce their ideas from sketches, without needing to learn the computer skills themselves.
Graphics Graphics are visual presentations on some surface such as a wall, canvas, computer screen, paper, or stone to brand, inform, illustrate, or entertain. Examples are photographs, drawings, Line Art, graphs, diagrams, typography, numbers, symbols, geometric designs, maps, engineering drawings, or other images. Graphics often combines text, illustration, and color. Graphics design may consist of the deliberate selection, creation, or arrangement of typography alone, as in a brochure, flier, poster, web site, or book without any other element. Clarity or effective communication may be the objective, association with other cultural elements may be sought, or merely, the creation of a distinctive style. Graphics can be functional or artistic. Graphics can be imaginary or represent something in the real world. The latter can be a recorded version, such as a photograph, or an interpretation by a scientist to highlight essential features, or an artist, in which case the distinction with imaginary graphics may get blurred.
History The earliest graphics known to anthropologists studying prehistoric periods are cave paintings and markings on boulders, bone, ivory, and antlers created during the Upper Palaeolithic period from 40,000 - 10,000 B.C. or earlier. Many of these were found to record astronomical, seasonal, and chronological details. Some of the earliest graphics and drawings known to the modern world, from almost 6,000 years ago, are that of engraved stone tablets and ceramic cylinder seals, marking the beginning of the historic periods and the keeping of records for accounting and inventory purposes. Records from Egypt predate these and papyrus was used by the Egyptians as a material on which to plan the building of pyramids; they also used slabs of limestone and wood. From 600-250 BC the Greeks played a major role in geometry. They used graphics to represent their mathematical theories such as the Circle Theorem and the Pythagorean theorem.
Drawing Drawing generally involves making marks on a surface by applying pressure from a tool, or moving a tool across a surface. Common tools are graphite pencils, pen and ink, inked brushes, wax color pencils, crayons, charcoals, pastels, and markers. Digital tools which
simulate the effects of these are also used. The main techniques used in drawing are: line drawing, hatching, crosshatching, random hatching, scribbling, stippling, and blending. Drawing is generally considered distinct from painting, in which colored pigments are suspended in a liquid medium and usually applied with a brush. Many great drawers include Sir Michael Ash and Leonardo da Vinci.
Painting In the Middle Ages paintings were very disorted, for example with people on a castle wall disproportionally large because they were what was important in the painting. Later realism and perspective became more important, symbolised by the use of a frame with a wire mesh that the painter would look through at the scene to precisely copy those dimensions on the canvas that had a corresponding grid drawn on it. During the Renaissance artists took a non-mathematical approach to drawing. Giotto di Bondone and Duccio di Buoninsegna made great advancements in graphics by using perspective drawing with the use of symmetry, converging lines and foreshortening. Many renaissance painters also used fresco - painting directly onto walls - a technique which finds its protoype in cave and rock art. Graphics of this kind from 30-40,000 years ago have survived in Australia and France. A modern day equivalent would be the mural.
Printmaking Printmaking originated in China after paper was invented (about A.D. 105). Relief printing first flourished in Europe in the 15th century, when the process of papermaking was imported from the East. Since that time, relief printing has been augmented by the various techniques described earlier, and printmaking has continued to be practiced as one of the fine arts.
Line Art Etching
Etching Etching is an intaglio method of printmaking in which the image is incised into the surface of a metal plate using an acid. The acid eats the metal, leaving behind roughened areas, or if the surface exposed to the acid is very narrow, burning a line into the plate. The process is believed to have been invented by Daniel Hopfer (circa 1470-1536) of Augsburg, Germany, who decorated armour in this way, and applied the method to printmaking. Etching is also used in the manufacturing of printed circuit boards and semiconductor devices.
Illustration
An Illustration is a visualisation such as drawing, painting, photograph or other work of art that stresses subject more than form. The aim of an Illustration is to elucidate or decorate a story, poem or piece of textual information (such as a newspaper article) Traditionally by providing a visual representation of something described in the text. The editorial cartoon, also known as a political cartoon, is an illustration containing a political or social message. Illustrations can be used to display a wide range of subject matter and serve a variety of functions like: •
giving faces to characters in a story;
• • • • •
displaying a number of examples of an item described in an academic textbook (e.g. A Typology); visualising step-wise sets of instructions in a technical manual. communicating subtle thematic tone in a narrative. linking brands to the ideas of human expression, invididuality and creativity. making a reader laugh or smile.
Graphs
A chart or graph is a type of information graphic that represents tabular numeric data. Charts are often used to make it easier to understand large quantities of data and the relationship between different parts of the data.
Diagrams A diagram is a simplified and structured visual representation of concepts, ideas, constructions, relations, statistical data, anatomy etc used in all aspects of human activities to visualize and clarify the topic.
Symbols A symbol, in its basic sense, is a conventional representation of a concept or quantity; i.e., an idea, object, concept, quality, etc. In more psychological and philosophical terms, all concepts are symbolic in nature, and representations for these concepts are simply token artifacts that are allegorical to (but do not directly codify) a symbolic meaning, or symbolism.
Geometric design Maps A map is a simplified depiction of a space, a navigational aid which highlights relations between objects within that space. Most usually a map is a two-dimensional, geometrically accurate representation of a three-dimensional space. One of the first 'modern' maps was made by Waldseemüller.
Photography
One difference between photography and other forms of Graphics is that a photographer, in principle, just records a single moment in reality. There doesn't seem to be any interpretation. But a photographer can choose the field of view and the angle and can use other techniques, such as various lenses to distort the view or filters to change the colours. In recent times digital photography has opened the way to an infinite number of fast but strong manipulations. Even in the early days of photography there was controversy over photographs of enacted scenes that were presented as 'real life' (especially in war photography, where it can be very difficult to record the original events). Shifting someone's pupils ever so slightly with simple pinpricks in the negative could have a dramatic effect. Just the choice of the field of view can have a strong effect, effectively 'censoring out' other parts of the scene, in other words cropping out selected parts or just avoiding including them in the photograph. This even touches on the philosophical question what reality is. Our eyes have their own way of recording visual information and our brains process that information based on previous experience, making us see just what we want to see or what we were taught to see. Photography can do (and even necessarily does) the same, except that someone else interprets for you. Of course, the same applies to other forms of graphics, but there it is obvious and accepted, and even expected because one wants to see not so much what an artist sees but how he sees it. In a different way this applies to technical and scientific drawings such as biological drawings, where one wants to see the essentials of something, say, an insect, not the specifics of this one insect (genotype in stead of phenotype).
Engineering drawings An engineering drawing is a type of drawing that is technical in nature, used to fully and clearly define requirements for engineered items, and is usually created in accordance with standardized conventions for layout, nomenclature, interpretation, appearance (such as typefaces and line styles), size, etc.
A graphic from the video game Half-Life 2.
Computer graphics In computer graphics there are two types of graphics: Raster, where each pixel is separately defined (as in a digital photograph), and vector, where mathematical formula are used to draw lines (eg 'take two points and draw a parabole between them'), which are then interpreted at the 'receiving end' to produce the graphic. Vectors make for in principle infinitely sharp graphics and usually smaller files, but when complex might render slower. In 1950 the first computer-driven display was attached to MIT's Whirlwind I computer to generate simple pictures. This was followed by MIT's TX-0 and TX-2- interactive computing which increased interest in computer graphics in the late 1950s. In 1962 Ivan Sutherland invented Sketchpad, an innovative program that influenced alternative forms of interaction with computers. In the mid-1960s large computer graphics research projects were begun at MIT, General Motors, Bell Labs, and Lockheed Aircraft. D. T. Ross of MIT developed an advanced compiler language for graphics programming. S.A.Coons, also at MIT, and J. C. Ferguson at Boeing, began work in sculptured surfaces. GM developed their DAC-1 system and other companies, such as Douglas, Lockheed, and McDonnell, also made significant developments. In 1968 Ray tracing was invented by Appel. During the late 1970s personal computers began to become more powerful and capable of drawing basic and complex shapes and designs. In the 1980s artists and graphic designers began to see the personal computer, particularly the Commodore Amiga and Macintosh, as a serious design tool that could save time and be used to draw more accurately than other methods. 3D computer graphics became possible in the late 1980s with the powerful SGI computers, which were later used to create some of the first fully computer-generated short films at Pixar. The Macintosh remains one of the most popular tools for computer graphics in graphic design studios and businesses. Modern computer systems dating from the 1980s and onwards often use a graphical user interface (GUI) to present data and information by using symbols, icons and pictures rather than text. Graphics is one of the five key elements of multimedia technology.
3D graphics became more popular in the 1990s in gaming, multimedia and animation. In 1996 Quake, one of the first fully 3D games, was released. In 1995 Toy Story, the first full-length computer-generated animation film, was released in cinemas worldwide. Since then computer graphics have become more accurate and more detailed because of more advanced computers and better 3D modeling software applications such as Cinema 4D. Another use of graphics on computers are screensavers, that originally had (and still have) the purpose of preventing the layout of much-used GUIs 'burning into' the computer screen, but have evolved into true pieces of art. The actual practical use of screensavers is now obsolete since modern screen are not succeptible to such "burning".
Web graphics
Signature art used on web forums In the 1990s Internet speeds increased, and Internet browsers capable of viewing images were released, the first being Mosaic. Websites began to use the GIF format to distribute small graphics such as banners, advertisements and navigation buttons on web pages. Web graphics are useful in providing a truly graphical user interface to websites rather than plain text. Modern browsers now support the use of jpeg, png and increasingly svg images in addition to gifs on web pages. A program like MS Paint in Microsoft Windows can be used by anyone, and more professional programs like Photoshop and Paint Shop Pro can give you more abilities but may be harder to use. Numerous websites have been created to host communities for web graphics artists. A growing community consists of people who use photoshop or paint shop pro to create forum signatures and other digital artwork.
Use Graphics are visual elements often used to point readers and viewers to particular information. They are also used to supplement text in an effort to aid readers in their understanding of a particular concept or make the concept more clear or interesting.
popular magazines, such as TIME, Wired and Newsweek, usually contain graphic material in abundance to attract readers, unlike the majority of scholarly journals. In computing, graphics are used as an interface for the user; and graphics is one of the five key elements of multimedia technology. Graphics are among the primary ways of advertising the sale of goods or services. It could be painted or drawn by hand, computer-generated graphics or photographed.
Business Graphics are commonly used in business and economics for financial charts and tables to represent Price and Quantity of a product. The term Business Graphics came into use in the late 1970s when personal computers became capable of drawing graphs and charts of data usually only displayed in tables, Business Graphics can be used to more easily notice changes over a period of time.
Advertising This is probably where most money is to be made with Graphics, to the extent that artists need to do advertising work beside the artistic work or even take advertising potential into account when creating art to increase the chances of selling the artwork.
Political The use of graphics - cartoons, graffiti, poster art, flag design etc - for overtly political purposes is a centuries old practice which thrives today in every part of the world. The Chiapas murals are one such example.
Education Graphics are heavily used in education in textbooks for subjects such as geography, science and math to illustrate theories and concepts. Diagrams are also used to label photographs and pictures. A common example of graphics in use to educate is diagrams of human anatomy. Educational animation is an important emerging field of graphics. Animated graphics can have advantages over static graphics for explaining subject matter that changes over time.
The Oxford Illustrated Dictionary uses graphics and technical illustrations to make reading material more interesting and easier to understand. In an encyclopedia graphics are used to illustrate concepts and show examples of a particular topic being discussed. In order for a graphic to function effectively as an educational aid, the learner must be able to interpret it successfully. This interpretative capacity is one aspect of graphicacy.
Film and animation Computer graphics are often used in the majority of new feature films, especially those with a large budget. Films to heavily use computer graphics include Spider-Man and War of the Worlds.
Graphics education The majority of schools, colleges and universities around the world educate students on the subject of graphics and art.
Famous graphic designers Aldus Manutius designed the first Italic type style which is often used in desktop publishing and graphic design. April Greiman is known for her influential poster design. Paul Rand is well known as a design pioneer for designing many popular corporate logos including the logo for IBM, NeXT and UPS. William Caslon during the mid-18th century designed many typefaces including ITC Founder's Caslon, ITC Founder's Caslon Ornaments, Caslon Graphique, ITC Caslon No. 224, Caslon Old Face and Big Caslon.
percent and related signs ( %, ‰, ) pilcrow ( ¶ ) prime ( ′ ) section sign ( § ) tilde ( ~ ) umlaut/diaeresis ( ¨ ) underscore/understrike ( _ ) vertical/pipe/broken bar ( |, ¦ ) Uncommon typography asterism ( ) lozenge ( ◊ ) interrobang ( ) irony mark ( ) reference mark ( sarcasm mark
)
A specimen of roman typefaces by William Caslon. Typography is the art and technique of setting written subject matter in type using a combination of fonts, font size, line length, leading (line spacing) and letter spacing.
Typography is performed by typesetters, compositors, typographers, graphic artists, art directors, and clerical workers. Until the Digital Age typography was a specialized occupation. Digitization opened up typography to new generations of visual designers and lay users.
Etymology and scope Typography (from the Greek words τύπος type = "to strike" "That by which something is symbolized or figured..." and γραφία graphia = to write). In contemporary use, the practice and study of typography is very broad, covering all aspects of letter design and application, including typesetting & typeface design; handwriting & calligraphy; graffiti; inscriptional & architectural lettering; poster design and other large scale lettering such as signage and billboards; business communications & promotional collateral; advertising; wordmarks & typographic logos (logotypes); apparel (clothing); vehicle instrument panels; kinetic typography in motion picture films and television; and as a component of industrial design—type resides on household appliances, pens and wristwatches. Since digitization typography's range of applications has become more eclectic, appearing on web pages, LCD mobile phone screens, and hand-held video games. The ubiquity of type has led typographers to coin the phrase "Type is everywhere". Typography generally follows four principles, using repetition, contrast, proximity, and alignment.
History Typography traces its origins to the first punches and dies used to make seals and currency in ancient times. Typography with modular moveable metal type began in 13thcentury Korea, and was developed again in mid-15th century Europe with the development of specialized techniques for casting and combining cheap copies of letter punches in the vast quantities required to print multiple copies of texts. For the origins and evolution of typography, see the main article History of typography
Text typography
Text typeset in Iowan Old Style roman, italics and small caps, optimised at approximately 10 words per line, typeface sized at 14 points on 1.4 x leading, with 0.2 points extra tracking. Extract of an essay by Oscar Wilde The Renaissance of English Art ca. 1882.
Text typeset using LaTeX digital typesetting software. Body matter, the matter prima of type In traditional typography, text is composed to create a readable, coherent, and visually satisfying whole that works invisibly—without the awareness of the reader. Even distribution with a minimum of distractions and anomalies are aimed at producing clarity and transparency. Choice of font(s) is perhaps the primary aspect of text typography—prose fiction, nonfiction, editorial, educational, religious, scientific, spiritual and commercial writing all have differing characteristics and requirements. For historic material, established text typefaces are frequently chosen according to a scheme of historical genre acquired by a long process of accretion, with considerable overlap between historical periods. Contemporary books are more likely to be set with state-of-the-art seriffed "text romans" or "book romans" with design values echoing present-day design arts, which are closely based on traditional models like Jenson, Aldines and Bembo. With their more specialized
requirements, newspapers and magazines rely on compact, tightly-fitted text romans specially designed for the task, which offer maximum flexibility, readability and efficient use of page space. Sans serif text fonts are used for introductory paragraphs, incidental text and whole short articles. A current fashion is to pair sans serif type for headings with a high-performance seriffed font of matching style for the text of an article. The text layout, tone or color of set matter, and the interplay of text with white space of the page and other graphic elements combine to impart a "feel" or "resonance" to the subject matter. With printed media typographers are also concerned with binding margins, paper selection and printing methods. Typography is modulated by Orthography and linguistics, word structures, word frequencies, morphology, phonetic constructs and linguistic syntax. Typography also is subject to specific cultural conventions. For example, in French it is customary to insert a non-breaking space before a colon (:) or semicolon (;) in a sentence, while in English it is not.
Readability and legibility Readability concerns how easily or comfortably a typeset text reads. Studies of readability suggest that our ability to read is based on recognition of individual glyph forms ("parallel letterwise recognition"), performed by the human brain's highly developed shape cognition facility. Text set in lower case is more readable, presumably because lower case letter structures are more distinctive, having greater saliency due to the presence of extenders (ascenders, descenders and othe projecting parts). Readers recognize the upper portions of letters more than the lower portions in the cognition process. Capital letters by comparison are of uniform height and less varied in structure, which is widely presumed to be the reason that all-capitals text is found to be less readable (poorer speed and comprehension) in tests of extended reading. Readability is compromised by letterspacing, word spacing and leading that are too tight or too loose. Generous leading separates lines of text, making it easier for the eye to distinguish one line from the next, or previous line. Poorly designed fonts and those that are too tightly or loosely fitted can result in poor readability. Some typographers believe that another factor, the Bouma or overall word shape, is also very important in readability, and that parallel letterwise recognition is either wrong, less
important, or not the entire picture. However, it seems that studies that would distinguish between between the two approaches have favored parallel letterwise recognition, so the latter is widely accepted among cognitive psychologists. Legibility is the ease and speed with which the reader can decipher each letterform and word. This is determined by the design of individual characters and how clearly they are rendered. Legibility can be affected by choice of ink and paper colors.
Newspapers, magazines, and periodicals
Popular American newspaper USAToday use typography heavily. Typography is used in all newspapers, magazines and periodicals. Headlines are often set in larger type to attract attention and are placed near the masthead. For example, USAToday use a bold, colorful and slightly modern style through their use of different fonts and colors; type sizes vary widely, and the newspaper name is placed on a color background. In contrast, New York Times use a more traditional approach with less colors, less font variation and more columns.
Display typography
Poster from the 19th century printed with wood and metal types. Typography is a potent element in graphic design, where there is less concern for readability and more potential for using type in an artistic manner. Type is combined with negative space, graphic elements and pictures, forming relationships and dialog between words and images. Color and size of type elements is much more prevalent than in text typography. Display typography exploits type at larger sizes, where the details of letter design are magnified. Display typography encompasses posters; book covers; typographic logos and wordmarks; billboards; packaging; on-product typography; calligraphy; graffitti; inscriptional & architectural lettering; poster design and other large scale lettering signage; business communications & promotional collateral; advertising; wordmarks & typographic logos (logotypes), and kinetic typography in motion pictures and television; vending machine displays; online & computer screen displays. The wanted poster for the assassins of Abraham Lincoln was printed with lead and woodcut type, and incorporates photography.
Inscriptional and architectural lettering
The history of inscriptional lettering is intimately tied to the history of writing, the evolution of letterforms, and the craft of the hand. The widespread use of the computer and various etching and sandblasting techniques today has made the hand carved monument a rarity, and the number of lettercarvers left in the States continues to dwindle. Most notable in the United States are John and Nick Benson who continue the work of the John Stevens Shop in Newport, RI, which was founded in 1705. The Stevens Shop has been responsible for the lettering on many of the highest profile monuments of the past several decades including the Vietnam Veterans Memorial, the John F Kennedy Memorial, the FDR Memorial, and, most recently, the World War II Memorial, yet their primary work is the design and carving of gravestones. For monumental lettering to be effective it must be considered carefully in its context. Proportions of letters need to be altered as their size and distance from the viewer increases. An expert letterer gains understanding of these nuances through much practice and observation of their craft. Letters drawn by hand and for a specific project have the possibility of being richly specific and profoundly beautiful in the hand of a master. Each can also take up to an hour to carve, so it is no wonder that the automated sandblasting process has become the industry standard. To create a sandblasted letter, a rubber mat is laser cut from a computer file and glued to the stone. The sand then bites a coarse groove or channel into the exposed surface. Unfortunately, many of the computer applications which create these files and interface with the laser cutter do not have many typefaces available, and often have inferior versions of typefaces that are available. What can now be done in minutes, however, lacks the striking architecture and geometry of the chisel-cut letter which allows light to play across its distinct interior planes. There are a number of online retailers of gravestones which offer fill-in forms, and a couple dozen clip-art borders and imagery, and some which cater to remembrances of your pet chihuahua, cockatiel, or llama. On the outer edge of gravestone technology there is the Vidstone Serenity Panel, a solar-powered LCD screen inlaid right into the stone which will play “a short personalized video tribute”. Recently, there has been some rumbling in typographic circles over the proposed 9/11 memorial in New Jersey. Frederic Schwartz, the project architect, has chosen to render the names of the victims, in his words, in “a familiar and easy-to-read typeface”: Times
New Roman. This democratic choice (the families of victims were closely involved with the design plan) could perhaps be echoing the controversial Emigre adage “People read best what they read most” in that Times is the default for many applications, but it seems to many that the choice is really a non-choice, or poor choice at best. These letterforms, originally designed for small print in newspaper setting, will be blown up to nearly four inches high. John Benson, speaking of his work in stone says, “You are making something that will outlast you. And I believe if you invest it with a certain honesty and the focus of your intellect and your sensitivities, those things are in the piece and are capable of being retrieved at a later date. That’s what art is all about, isn’t it?” (quoted in Kathleen Silver’s “Men of Letters”) Inscriptional typography can certainly rise to this level of intellectual and physical quality, as can be seen in the recent choice of Gotham for the World Trade Cornerstone, but too often our culture settles for unconsidered and unthoughtful lettering for even our most important visual memorials.
Advertising
A print advertisement from a 1913 issue of National Geographic Typography has long been a vital part of promotional material and advertising. Designers often use typography to set a theme and mood in an advertisement; for example using bold, large text to convey a particular message to the reader. Type is often used to draw attention to a particular advertisement, combined with efficient use of color, shapes and images. Today, typography in advertising often reflects a company's brand. Fonts used in advertisements convey different messages to the reader, classical fonts are for a strong personality, while more modern fonts are for a cleaner, neutral look. Bold fonts are used for making statements and attracting attention.
Graphic image development
Graphic image development, or simply image development, is a term used to encompass the production of graphics (mainly computer graphics) for use in media. Since the computer has merged skills such as illustrating, photography, photo editing, 3-D modeling, and handicraft, creative professionals have used "image development" as a more flexible term to avoid over-specifying or limiting options in the design process. The merging of the skills has led to multi-skilled image development artists. Photographers may become digital artists. Illustrators may become animators. Handicraft may be computer-aided or use computer generated imagery as a template. The term is also used to distinguish the process of preparing elements for use in media (e.g. photographs, illustrations, charts) from the process of composing elements (e.g. page layout, web development, film editing, desktop publishing) to a single presentation piece (e.g. brochure, web page, movie, billboard). Artists that know composition skills may also know image development skills. They may do the image development themselves or collaborate with other individually skilled imaged developers. Collaboration with image developers is used more often with higher budget projects and projects that require rare or completely unique image development styles. The term is not to be confused with the development process for the corporate image called branding. The term is also in contrast to image editing which excludes the capturing of images and creation of images from scratch. Image development also
Digital image A digital image is a representation of a two-dimensional image as a finite set of digital values, called picture elements or pixels. Typically, the pixels are stored in computer memory as a raster image or raster map, a two-dimensional array of small integers. These values are often transmitted or stored in a compressed form. Digital images can be created by a variety of input devices and techniques, such as digital cameras, scanners, coordinate-measuring machines, seismographic profiling, airborne radar, and more. They can also be synthetized from arbitrary non-image data, such as mathematical functions or three-dimensional geometric models; the latter being a major sub-area of computer graphics. The field of digital image processing is the study of algorithms for their transformation.
Image types Each pixel of an image is typically associated to a specific 'position' in some 2D region, and has a value consisting of one or more quantities (samples) related to that position. Digital images can be classified according to the number and nature of those samples: • • • • • •
binary (bilevel) grayscale color false-color multi-spectral thematic
The term digital image is also applied to data associated to points scattered over a threedimensional region, such as produced by tomographic equipment. In that case, each datum is called a voxel.
Image viewing The user can utilize different program to see the image. The GIF, JPEG and PNG images can be seen simply using a web browser because they are the standard internet image
formats. The SVG format is more and more used in the web and is a standard W3C format. Some viewers offer a slideshow utility, to see the images in a certain folder one after the other automatically.
Image calibration Proper use of a digital image usually requires knowledge of the relationship between it and the underlying phenomenon, which implies geometric and photometric (or sensor) calibration. One must also keep in mind the unavoidable errors that arise from the finite spatial resolution of the pixel array and the need to quantize each sample to a finite set of possible values.
Digital image editing Digital image editing is the process of altering digital images, whether they be digital photographs or other types of digitally represented images. Specialised software programs called vector graphics editors or raster graphics editors are the primary tools with which a user may manipulate, enhance, and transform images. These editors are capable of editing images in many diverse ways. Digital imaging is closely associated with digital photography and is used extensively in the fields of digital art, science, medicine, and forensics.
Basics of image editing Raster images are stored in a computer in the form of a grid of picture elements called pixels. These pixels contain the image's color and brightness information. Image editors can change the pixels to enhance the image in many ways. The pixels can be changed as a group, or individually, by the sophisticated algorithms within the image editors. The domain of this article primarily refers to bitmap graphics editors, which are often used to alter photographs and other raster graphics. However, vector-based software, such as
Adobe Illustrator can be used to alter or construct other types of image, namely ones based upon vectors. Adobe Photoshop is the most common application commercialy used for digitaly manipulating images.
Image editing programs Because of the popularity of digital cameras, image editing programs are readily available. Minimal programs, that perform such operations as rotating and cropping are often provided within the digital camera itself, while others are returned to the user on a compact disc (CD) when images are processed at a discount store. The more powerful programs contain functionality to perform a large variety of advanced image manipulations. Popular raster-based digital image editors include Adobe Photoshop, Corel Photo-Paint, Paint Shop Pro, Visualizer Photo Studio, Pixel image editor, PixBuilder Photo Editor, Fo2Pix ArtMaster, the GIMP, and Paint.net. For more, including free programs, see: List of raster graphics editors.
Digital data compression Many image file formats use data compression to reduce file size and save storage space. Digital compression of images may take place in the camera, or can be done in the computer with the image editor. When images are stored in JPEG format, compression has already taken place. Both cameras and computer programs allow the user to set the level of compression. Some compression algorithms are lossless, such as PNG, which means no image quality is lost when the file is saved. The JPEG compression algorithm uses a lossy format. The greater the compression, the lesser the quality. It utilizes the way the brain and eyes perceive color to make loss of detail less noticeable.
Image editor features Listed below are some of the most used capabilities of the better graphic manipulation programs. The list is by no means all inclusive. There are a myriad of choices associated with the application of most of these features.
Selection
One of the prerequisites for many of the applications mentioned below is a method of selecting part(s) of an image, thus applying a change selectively without affecting the entire picture. Most graphics programs have several means of accomplishing this, such as a marquee tool, lasso, vector-based pen tools as well as more advanced facilities such as edge detection, masking, alpha compositing, and color and channel-based extraction.
Layers Another feature common to many graphics applications is that of Layers, which are analogous to sheets of transparent acetate (each containing separate elements that make up a combined picture), stacked on top of each other, each capable of being individually positioned, altered and blended with the layers below, without affecting any of the elements on the other layers. This is a fundamental workflow which has become the norm for the majority of programs on the market today, and enables maximum flexibility for the user whilst maintaining non-destructive editing principles and ease of use.
Image size alteration Image editors can resize images in a process often called image scaling, making them larger, or smaller. High image resolution cameras can produce large images which are often reduced in size for Internet use. Image editor programs use a mathematical process called resampling to calculate new pixel values whose spacing is larger or smaller than the original pixel values. Images for Internet use are kept small, say 640 x 480 pixels which would equal 0.3 megapixels.
Cropping an image
Vector graphics editor
A screenshot of the xfig vector graphics editor
A screenshot of the modern vector graphics editor Xara Xtreme A vector graphics editor is a computer program that allows users to compose and edit vector graphics images interactively on the computer screen (compare with MetaPost) and save them in one of many popular vector graphics formats such as EPS, PDF, WMF or SVG.
Vector editors versus bitmap editors Vector editors are often contrasted with bitmap editors, and their capabilities complement each other. Vector editors are better for graphic design, page layout, typography, logos, sharp-edged artistic illustrations (i.e. cartoons, clip art, complex geometric patterns), technical illustrations, diagramming and flowcharting. Bitmap editors are more suitable for retouching, photo processing, and photorealistic illustrations. The recent versions of bitmap editors, such as GIMP and Photoshop, support vector-like tools (e.g. editable paths), and the vector editors such as CorelDraw, Adobe Illustrator or Xara Xtreme gradually adapt tools and approaches that were once limited to bitmap editors (e.g. blurring).
Specialized features Some vector editors support animation, while others (e.g. Macromedia Flash) are specifically geared towards producing animated graphics. Generally, vector graphics are more suitable for animation, though there are raster-based animation tools as well. Vector editors are closely related to desktop publishing software such as Adobe InDesign or Scribus, which also usually include some vector drawing tools (usually less powerful than those in standalone vector editors). Modern vector editors are capable of, and often preferable for, designing unique documents (like flyers or brochures) of up to a few
pages; it's only for longer or more standardized documents that the page layout programs are more suitable. Special vector editors are used for Computer Assisted Drafting. They are not suitable for artistic or decorative graphics, but are rich in tools and object libraries used to ensure precision and standards compliance of drawings and blueprints. Finally, 3D computer graphics software such as Maya or Blender can also be thought of as an extension of the traditional 2D vector editors, and they share some common concepts and tools.
Raster graphics editor
A screenshot from the KDE raster graphics editor KolourPaint
A screenshot from the GIMP raster graphics editor A raster graphics editor is a computer program that allows users to paint and edit pictures interactively on the computer screen and save them in one of many popular "bitmap" or "raster" formats such as JPEG, PNG, GIF and TIFF. Usually an image viewer is preferred over a raster graphics editor for viewing images.
Some features common to many raster graphics editors are:
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Select a region for editing. Draw lines with brushes of different color, size, shape and pressure Fill in a region with a single color, gradient of colors, or a texture. Select a color using different color models (e.g. RGB, HSV), or by using a color dropper. Add typed letters in different font styles. Remove scratches, dirt, wrinkles, and imperfections from photo images. Composite editing using layers. Edit and convert between various color models. Apply various filters for effects like sharpening and blurring. Convert between various image formats.
Computer graphics Computer graphics (CG) is the field of visual computing, where one utilizes computers both to generate visual images synthetically and to integrate or alter visual and spatial information sampled from the real world. William Fetter was credited with coining the term Computer Graphics in 1960, to describe his work at Boeing. The first major advance in computer graphics was the development of Sketchpad in 1962 by Ivan Sutherland. This field can be divided into several areas: real-time 3D rendering (often used in video games), computer animation, video capture and video creation rendering, special effects editing (often used for movies and television), image editing, and modeling (often used for engineering and medical purposes). Development in computer graphics was first fueled by academic interests and government sponsorship. However, as real-world applications of computer graphics in broadcast television and movies proved a viable alternative to more traditional special effects and animation techniques, commercial parties have increasingly funded advances in the field. It is often thought that the first feature film to use computer graphics was 2001: A Space Odyssey (1968), which attempted to show how computers would be much more graphical in the future. However, all the "computer graphic" effects in that film were hand-drawn animation, and the special effects sequences were produced entirely with conventional optical and model effects. Perhaps the first use of computer graphics specifically to illustrate computer graphics was in Futureworld (1976), which included an animation of a human face and hand-produced by Ed Catmull and Fred Parke at the University of Utah.
3D With the birth of workstation computers (like LISP machines, paintbox computers and Silicon Graphics workstations) came 3D computer graphics, based on vector graphics. Instead of the computer storing information about points, lines, and curves on a 2dimensional plane, the computer stores the location of points, lines, and, typically, faces (to construct a polygon) in 3-dimensional space.
3-dimensional polygons are the lifeblood of virtually all 3D computer graphics. As a result, most 3D graphics engines are based around storing points (single 3-dimensional coordinates), lines that connect those points together, faces defined by the lines, and then a sequence of faces to create 3D polygons. Modern-day computer graphics software goes far beyond just the simple storage of polygons in computer memory. Today's graphics are not only the product of massive collections of polygons into recognizable shapes, but they also result from techniques in shading, texturing, and rasterization.
Shading Shading in hand-drawn graphics can be done in several ways; for example, taking a pencil, flipping it to the side, and stroking it over the paper while applying light pressure. In the context of 3D computer graphics, the process of shading involves the computer simulating (or, more accurately, calculating) how the faces of a polygon will look when illuminated by a virtual light source. The exact calculation varies depending not only on what data is available about the face being shaded, but also on the shading technique.
Image-Based Rendering Computer graphics is all about obtaining 2D images from 3D models. In order to get highly accurate and photo-realistic images, the input 3D models should be very accurate in terms of geometry and colors. Simulating the real 3D world scene using Computer Graphics is difficult, because obtaining accurate 3D geometry of the world is difficult. Instead of obtaining 3D models, image-based rendering (IBR) uses the images taken from particular view points and tries to obtain new images from other view points. Though the term "image-based rendering" was coined recently, it has been in practice since the inception of research in computer vision. In 1996, two image-based rendering techniques were presented in SIGGRAPH: light field rendering and Lumigraph rendering. These techniques received special attention in the research community. Since then, many representations for IBR were proposed. One popular method is view-dependent texture mapping, an IBR technique from University of Southern California. Andrew Zisserman, et. al from Oxford University used machine learning concepts for IBR.
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Flat shading: A technique that shades each polygon of an object based on the polygon's "normal" and the position and intensity of a light source. Gouraud shading: Invented by Henri Gouraud in 1971, a fast and resourceconscious technique used to simulate smoothly shaded surfaces by interpolating vertex colors across a polygon's surface. Texture mapping: A technique for simulating surface detail by mapping images (textures) onto polygons. Phong shading: Invented by Bui Tuong Phong, a smooth shading technique that approximates curved-surface lighting by interpolating the vertex normals of a polygon across the surface; the lighting model includes glossy reflection with a controllable level of gloss. Bump mapping: Invented by Jim Blinn, a normal-perturbation technique used to simulate bumpy or wrinkled surfaces. Normal mapping: Related to bump mapping, a more in-depth way of simulating bumps, wrinkles, or other intricate details into low-polygon models. Ray tracing: A rendering method based on the physical principles of geometric optics that can simulate multiple reflections and transparency. Radiosity: a technique for global illumination that uses radiative transfer theory to simulate indirect (reflected) illumination in scenes with diffuse surfaces. Blobs: a technique for representing surfaces without specifying a hard boundary representation, usually implemented as a procedural surface like a Van der Waals equipotential (in chemistry).
Texturing Polygon surfaces (the sequence of faces) can contain data corresponding to not only a color but, in more advanced software, can be a virtual canvas for a picture, or other rasterized image. Such an image is placed onto a face or NURBs "patch" using texture space coordinates or UV's, or series of faces, and is called a texture. Textures add a new degree of customization as to how faces and polygons will ultimately look after being shaded, depending on the shading method, and how the image is interpreted during shading. One method of combining textures is called Texture Splatting.
Rendering (computer graphics)
A photorealistic rendered image created by using POV-Ray 3.6. The glasses, ashtray and pitcher were modeled with Rhinoceros 3D and the dice with Cinema 4D. Rendering is the process of generating an image from a model, by means of software programs. The model is a description of three dimensional objects in a strictly defined language or data structure. It would contain geometry, viewpoint, texture and lighting information. The image is a digital image or raster graphics image. The term may be by analogy with an "artist's rendering" of a scene. 'Rendering' is also used to describe the process of calculating effects in a video editing file to produce final video output. It is one of the major sub-topics of 3D computer graphics, and in practice always connected to the others. In the 'graphics pipeline' it's the last major step, giving the final appearance to the models and animation. With the increasing sophistication of computer graphics since the 1970s onward, it has become a more distinct subject. It has uses in: computer and video games, simulators, movies or TV special effects, and design visualisation, each employing a different balance of features and techniques. As a product, a wide variety of renderers are available. some are integrated into larger modelling and animation packages, some are stand-alone, some are free open-source projects. On the inside, a renderer is a carefully engineered program, based on a selective mixture of disciplines related to: light physics, visual perception, mathematics, and software development. In the case of 3D graphics, rendering may be done slowly, as in pre-rendering, or in real time. Pre-rendering is a computationally intensive process that is typically used for movie
creation, while real-time rendering is often done for 3D video games which rely on the use of graphics cards with 3D hardware accelerators.
Usage When the pre-image (a wireframe sketch usually) is complete, rendering is used, which adds in bitmap textures or procedural textures, lights, bump mapping, and relative position to other objects. The result is a completed image the consumer or intended viewer sees. For movie animations, several images (frames) must be rendered, and stitched together in a program capable of making an animation of this sort. Most 3D image editing programs can do this.
Features A rendered image can be understood in terms of a number of visible features. Rendering research and development has been largely motivated by finding ways to simulate these efficiently. Some relate directly to particular algorithms and techniques, while others are produced together. • • • • • • • • • • • •
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shading — how the color and brightness of a surface varies with lighting texture-mapping — a method of applying detail to surfaces bump-mapping — a method of simulating small-scale bumpiness on surfaces fogging/participating medium — how light dims when passing through nonclear atmosphere or air shadows — the effect of obstructing light soft shadows — varying darkness caused by partially obscured light sources reflection — mirror-like or highly glossy reflection transparency — sharp transmission of light through solid objects translucency — highly scattered transmission of light through solid objects refraction — bending of light associated with transparency indirect illumination — surfaces illuminated by light reflected off other surfaces, rather than directly from a light source caustics (a form of indirect illumination) — reflection of light off a shiny object, or focusing of light through a transparent object, to produce bright highlights on another object depth of field — objects appear blurry or out of focus when too far in front of or behind the object in focus motion blur — objects appear blurry due to high-speed motion, or the motion of the camera
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photorealistic morphing — photoshopping 3D renderings to appear more lifelike non-photorealistic rendering — rendering of scenes in an artistic style, intended to look like a painting or drawing
Techniques Many rendering algorithms have been researched, and software used for rendering may employ a number of different techniques to obtain a final image. Tracing every ray of light in a scene would be impractical and would take gigantic amounts of time. Even tracing a portion large enough to produce an image takes an inordinate amount of time if the sampling is not intelligently restricted. Therefore, four loose families of more-efficient light transport modelling techniques have emerged: rasterisation, including scanline rendering, considers the objects in the scene and projects them to form an image, with no facility for generating a point-of-view perspective effect; ray casting considers the scene as observed from a specific point-ofview, calculating the observed image based only on geometry and very basic optical laws of reflection intensity, and perhaps using Monte Carlo techniques to reduce artifacts; radiosity uses finite element mathematics to simulate diffuse spreading of light from surfaces; and ray tracing is similar to ray casting, but employs more advanced optical simulation, and usually uses Monte Carlo techniques, to obtain more realistic results, at a speed which is often orders of magnitude slower. Most advanced software combines two or more of the techniques to obtain good-enough results at reasonable cost.
Scanline rendering and rasterisation A high-level representation of an image necessarily contains elements in a different domain from pixels. These elements are referred to as primitives. In a schematic drawing, for instance, line segments and curves might be primitives. In a graphical user interface, windows and buttons might be the primitives. In 3D rendering, triangles and polygons in space might be primitives. If a pixel-by-pixel approach to rendering is impractical or too slow for some task, then a primitive-by-primitive approach to rendering may prove useful. Here, one loops through
each of the primitives, determines which pixels in the image it affects, and modifies those pixels accordingly. This is called rasterization, and is the rendering method used by all current graphics cards. Rasterization is frequently faster than pixel-by-pixel rendering. First, large areas of the image may be empty of primitives; rasterization will ignore these areas, but pixel-bypixel rendering must pass through them. Second, rasterization can improve cache coherency and reduce redundant work by taking advantage of the fact that the pixels occupied by a single primitive tend to be contiguous in the image. For these reasons, rasterization is usually the approach of choice when interactive rendering is required; however, the pixel-by-pixel approach can often produce higher-quality images and is more versatile because it does not depend on as many assumptions about the image as rasterization. Rasterization exists in two main forms, not only when an entire face (primitive) is rendered but when the vertices of a face are all rendered and then the pixels on the face which lie between the vertices rendered using simple blending of each vertex colour to the next, this version of rasterization has overtaken the old method as it allows the graphics to flow without complicated textures (a rasterized image when used face by face tends to have a very block-like effect if not covered in complex textures; the faces aren't smooth because there is no gradual color change from one pixel to the next), utilizing the graphics card's more taxing shading functions and still achieving better performance because the simpler textures stored in memory use less space. Sometimes designers will use one rasterization method on some faces and the other method on others based on the angle at which that face meets other joined faces, thus increasing speed and not hurting the overall effect.
Ray casting Ray casting is primarily used for realtime simulations, such as those used in 3D computer games and cartoon animations, where detail is not important, or where it is more efficient to manually fake the details in order to obtain better performance in the computational stage. This is usually the case when a large number of frames need to be animated. The resulting surfaces have a characteristic 'flat' appearance when no additional tricks are used, as if objects in the scene were all painted with matte finish.
The geometry which has been modeled is parsed pixel by pixel, line by line, from the point of view outward, as if casting rays out from the point of view. Where an object is intersected, the color value at the point may be evaluated using several methods. In the simplest, the color value of the object at the point of intersection becomes the value of that pixel. The color may be determined from a texture-map. A more sophisticated method is to modify the colour value by an illumination factor, but without calculating the relationship to a simulated light source. To reduce artifacts, a number of rays in slightly different directions may be averaged. Rough simulations of optical properties may be additionally employed: a simple calculation of the ray from the object to the point of view is made. Another calculation is made of the angle of incidence of light rays from the light source(s), and from these as well as the specified intensities of the light sources, the value of the pixel is calculated. Another simulation uses illumination plotted from a radiosity algorithm, or a combination of these two.
Radiosity Radiosity is a method which attempts to simulate the way in which reflected light, instead of just reflecting to another surface, also illuminates the area around it. This produces more realistic shading and seems to better capture the 'ambience' of an indoor scene. A classic example used is of the way that shadows 'hug' the corners of rooms. The optical basis of the simulation is that some diffused light from a given point on a given surface is reflected in a large spectrum of directions and illuminates the area around it. The simulation technique may vary in complexity. Many renderings have a very rough estimate of radiosity, simply illuminating an entire scene very slightly with a factor known as ambiance. However, when advanced radiosity estimation is coupled with a high quality ray tracing algorithim, images may exhibit convincing realism, particularly for indoor scenes. In advanced radiosity simulation, recursive, finite-element algorithms 'bounce' light back and forth between surfaces in the model, until some recursion limit is reached. The colouring of one surface in this way influences the colouring of a neighbouring surface, and vice versa. The resulting values of illumination throughout the model (sometimes
including for empty spaces) are stored and used as additional inputs when performing calculations in a ray-casting or ray-tracing model. Due to the iterative/recursive nature of the technique, complex objects are particularly slow to emulate. Advanced radiosity calculations may be reserved for calulating the ambiance of the room, from the light reflecting off walls, floor and celiing, without examining the contribution that complex objects make to the radiosity -- or complex objects may be replaced in the radiosity calculation with simpler objects of similar size and texture. If there is little rearrangement of radiosity objects in the scene, the same radiosity data may be reused for a number of frames, making radiosity an effective way to improve on the flatness of ray casting, without seriously impacting the overall rendering time-perframe. Because of this, radiosity has become the leading real-time rendering method, and has been used to beginning-to-end create a large number of well-known recent feature-length animated 3D-cartoon films.
Ray tracing Ray tracing is an extension of the same technique developed in scanline rendering and ray casting. Like those, it handles complicated objects well, and the objects may be described mathematically. Unlike scanline and casting, ray tracing is almost always a Monte Carlo technique, that is one based on averaging a number of randomly generated samples from a model. In this case, the samples are imaginary rays of light intersecting the viewpoint from the objects in the scene. It is primarily beneficial where complex and accurate rendering of shadows, refraction or reflection are issues. In a final, production quality rendering of a ray traced work, multiple rays are generally shot for each pixel, and traced not just to the first object of intersection, but rather, through a number of sequential 'bounces', using the known laws of optics such as "angle of incidence equals angle of reflection" and more advanced laws that deal with refraction and surface roughness.
Once the ray either encounters a light source, or more probably once a set limiting number of bounces has been evaluated, then the surface illumination at that final point is evaluated using techniques described above, and the changes along the way through the various bounces evaluated to estimate a value observed at the point of view. This is all repeated for each sample, for each pixel. In some cases, at each point of intersection, multiple rays may be spawned. As a brute-force method, raytracing has been too slow to consider for realtime, and until recently too slow even to consider for short films of any degree of quality, although it has been used for special effects sequences, and in advertising, where a short portion of high quality (perhaps even photorealistic) footage is required. However, efforts at optimising to reduce the number of calculations needed in portions of a work where detail is not high or does not depend on raytracing features have led to a realistic possibility of wider use of ray tracing. There is now some hardware accelerated ray tracing equipment, at least in prototype phase, and some game demos which show use of realtime software or hardware ray tracing.
Optimisation Optimisations used by an artist when a scene is being developed Due to the large number of calulations, a work in progress is usually only rendered in detail appropriate to the portion of the work being developed at a given time, so in the initial stages of modelling, wireframe and ray casting may be used, even where the target output is ray tracing with radiosity. It is also common to render only parts of the scene at high detail, and to remove objects that are not important to what is currently being developed.
Common optimisations for real time rendering For real-time, it is appropriate to simplify one or more common approximations, and tune to the exact parameters of the scenery in question, which is also tuned to the agreed parameters to get the most 'bang for the buck'. There are some lesser known approaches to rendering, such as spherical harmonics. These techniques are lesser known often due to slow speed, lack of practical use or
simply because they are in early stages of development; maybe some will offer a new solution.
Sampling and filtering One problem that any rendering system must deal with, no matter which approach it takes, is the sampling problem. Essentially, the rendering process tries to depict a continuous function from image space to colors by using a finite number of pixels. As a consequence of the Nyquist theorem, the scanning frequency must be twice the dot rate, which is proportional to image resolution. In simpler terms, this expresses the idea that an image cannot display details smaller than one pixel. If a naive rendering algorithm is used, high frequencies in the image function will cause ugly aliasing to be present in the final image. Aliasing typically manifests itself as jaggies, or jagged edges on objects where the pixel grid is visible. In order to remove aliasing, all rendering algorithms (if they are to produce good-looking images) must filter the image function to remove high frequencies, a process called antialiasing. Rendering for movies often takes place on a network of tightly connected computers known as a render farm. The current state of the art in 3-D image description for movie creation is the RenderMan scene description language designed at Pixar. (compare with simpler 3D fileformats such as VRML or APIs such as OpenGL and DirectX tailored for 3D hardware accelerators). Movie type rendering software includes: • • • • •
RenderMan compliant renderers Mental Ray Brazil Blender (may also be used for modeling) LightWave (includes modelling module)
Academic core The implementation of a realistic renderer always has some basic element of physical simulation or emulation — some computation which resembles or abstracts a real physical process.
The term "physically-based" indicates the use of physical models and approximations that are more general and widely accepted outside rendering. A particular set of related techniques have gradually become established in the rendering community. The basic concepts are moderately straightforward, but intractable to calculate; and a single elegant algorithm or approach has been elusive for more general purpose renderers. In order to meet demands of robustness, accuracy, and practicality, an implementation will be a complex combination of different techniques. Rendering research is concerned with both the adaptation of scientific models and their efficient application.
The rendering equation This is the key academic/theoretical concept in rendering. It serves as the most abstract formal expression of the non-perceptual aspect of rendering. All more complete algorithms can be seen as solutions to particular formulations of this equation.
Meaning: at a particular position and direction, the outgoing light (Lo) is the sum of the emitted light (Le) and the reflected light. The reflected light being the sum of the incoming light (Li) from all directions, multiplied by the surface reflection and incoming angle. By connecting outward light to inward light, via an interaction point, this equation stands for the whole 'light transport' — all the movement of light — in a scene.
The Bidirectional Reflectance Distribution Function The Bidirectional Reflectance Distribution Function (BRDF) expresses a simple model of light interaction with a surface as follows:
Light interaction is often approximated by the even simpler models: diffuse reflection and specular reflection, although both can be BRDFs.
Geometric optics
Rendering is practically exclusively concerned with the particle aspect of light physics — known as geometric optics. Treating light, at its basic level, as particles bouncing around is a simplification, but appropriate: the wave aspects of light are negligible in most scenes, and are significantly more difficult to simulate. Notable wave aspect phenomena include diffraction — as seen in the colours of CDs and DVDs — and polarisation — as seen in LCDs. Both types of effect, if needed, are made by appearance-oriented adjustment of the reflection model.
Visual perception Though it receives less attention, an understanding of human visual perception is valuable to rendering. This is mainly because image displays and human perception have restricted ranges. A renderer can simulate an almost infinite range of light brightness and color, but current displays — movie screen, computer monitor, etc. — cannot handle so much, and something must be discarded or compressed. Human perception also has limits, and so doesn't need to be given large-range images to create realism. This can help solve the problem of fitting images into displays, and, furthermore, suggest what shortcuts could be used in the rendering simulation, since certain subtleties won't be noticeable. This related subject is tone mapping. Mathematics used in rendering includes: linear algebra, calculus, numerical mathematics, signal processing, monte carlo.
3D computer graphics
A 3D rendering with raytracing and ambient occlusion using Blender and Yafray 3D computer graphics are works of graphic art that were created with the aid of digital computers and specialized 3D software. In general, the term may also refer to the process of creating such graphics, or the field of study of 3D computer graphic techniques and its related technology. 3D computer graphics are different from 2D computer graphics in that a threedimensional representation of geometric data is stored in the computer for the purposes of performing calculations and rendering 2D images. Sometimes these images are later displayed in a pre-rendered form, and sometimes they are rendered in real-time. In general, the art of 3D modeling, which prepares geometric data for 3D computer graphics is akin to sculpting or photography, while the art of 2D graphics is analogous to painting. However, 3D computer graphics rely on many of the same algorithms as 2D computer graphics. In computer graphics software, this distinction is occasionally blurred; some 2D applications use 3D techniques to achieve certain effects such as lighting, while some primarily 3D applications make use of 2D visual techniques.
Technology OpenGL and Direct3D are two popular APIs for the generation of real-time imagery. (Real-time means that image generation occurs in 'real time', or 'on the fly') Many modern graphics cards provide some degree of hardware acceleration based on these
APIs, frequently enabling the display of complex 3D graphics in real-time. However, it's not necessary to employ any one of these to actually create 3D imagery.
Creation of 3D computer graphics
Architectural rendering compositing of modeling and lighting finalized by rendering process The process of creating 3D computer graphics can be sequentially divided into three basic phases: • • •
Modeling Scene layout setup Rendering
Modeling The modeling stage could be described as shaping individual objects that are later used in the scene. There exist a number of modeling techniques, including, but not limited to the following: • • • • •
Modeling processes may also include editing object surface or material properties (e.g., color, luminosity, diffuse and specular shading components — more commonly called roughness and shininess, reflection characteristics, transparency or opacity, or index of refraction), adding textures, bump-maps and other features.
Modeling may also include various activities related to preparing a 3D model for animation (although in a complex character model this will become a stage of its own, known as rigging). Objects may be fitted with a skeleton, a central framework of an object with the capability of affecting the shape or movements of that object. This aids in the process of animation, in that the movement of the skeleton will automatically affect the corresponding portions of the model. See also Forward kinematic animation and Inverse kinematic animation. At the rigging stage, the model can also be given specific controls to make animation easier and more intuitive, such as facial expression controls and mouth shapes (phonemes) for lipsyncing. Modeling can be performed by means of a dedicated program (e.g., Lightwave Modeler, Rhinoceros 3D, Moray), an application component (Shaper, Lofter in 3D Studio) or some scene description language (as in POV-Ray). In some cases, there is no strict distinction between these phases; in such cases modelling is just part of the scene creation process (this is the case, for example, with Caligari trueSpace and Realsoft 3D).
Process
A 3D scene of 8 red glass balls
Scene layout setup Scene setup involves arranging virtual objects, lights, cameras and other entities on a scene which will later be used to produce a still image or an animation. If used for animation, this phase usually makes use of a technique called "keyframing", which facilitates creation of complicated movement in the scene. With the aid of keyframing, instead of having to fix an object's position, rotation, or scaling for each frame in an
animation, one needs only to set up some key frames between which states in every frame are interpolated. Lighting is an important aspect of scene setup. As is the case in real-world scene arrangement, lighting is a significant contributing factor to the resulting aesthetic and visual quality of the finished work. As such, it can be a difficult art to master. Lighting effects can contribute greatly to the mood and emotional response effected by a scene, a fact which is well-known to photographers and theatrical lighting technicians.
Tessellation and meshes The process of transforming representations of objects, such as the middle point coordinate of a sphere and a point on its circumference into a polygon representation of a sphere, is called tessellation. This step is used in polygon-based rendering, where objects are broken down from abstract representations ("primitives") such as spheres, cones etc, to so-called meshes, which are nets of interconnected triangles. Meshes of triangles (instead of e.g. squares) are popular as they have proven to be easy to render using scanline rendering. Polygon representations are not used in all rendering techniques, and in these cases the tessellation step is not included in the transition from abstract representation to rendered scene.
Rendering Rendering is the final process of creating the actual 2D image or animation from the prepared scene. This can be compared to taking a photo or filming the scene after the setup is finished in real life. Rendering for interactive media, such as games and simulations, is calculated and displayed in real time, at rates of approximately 20 to 120 frames per second. Animations for non-interactive media, such as video and film, are rendered much more slowly. Nonreal time rendering enables the leveraging of limited processing power in order to obtain higher image quality. Rendering times for individual frames may vary from a few seconds to an hour or more for complex scenes. Rendered frames are stored on a hard disk, then possibly transferred to other media such as motion picture film or optical disk.
These frames are then displayed sequentially at high frame rates, typically 24, 25, or 30 frames per second, to achieve the illusion of movement. Several different, and often specialized, rendering methods have been developed. These range from the distinctly non-realistic wireframe rendering through polygon-based rendering, to more advanced techniques such as: scanline rendering, ray tracing, or radiosity. In general, different methods are better suited for either photo-realistic rendering, or real-time rendering. In real-time rendering, the goal is to show as much information as possible as the eye can process in a 30th of a second. The goal here is primarily speed and not photo-realism. In fact, here exploitations are made in the way the eye 'perceives' the world, and thus the final image presented is not necessarily that of the real-world, but one which the eye can closely associate to. This is the basic method employed in games, interactive worlds, VRML. However, the rapid increase in computer processing power, allowed a progressively higher degree of realism even for real-time rendering, including techniques such as HDR rendering. Real-time rendering is often polygonal and aided by the computer's GPU.
An example of a ray-traced image that typically takes seconds or minutes to render. The photo-realism is apparent. When the goal is photo-realism, techniques are employed such as ray tracing or radiosity. Rendering often takes of the order of seconds or sometimes even days (for a single image/frame). This is the basic method employed in digital media and artistic works, etc.
Rendering software may simulate such visual effects as lens flares, depth of field or motion blur. These are attempts to simulate visual phenomena resulting from the optical characteristics of cameras and of the human eye. These effects can lend an element of realism to a scene, even if the effect is merely a simulated artifact of a camera. Techniques have been developed for the purpose of simulating other naturally-occurring effects, such as the interaction of light with various forms of matter. Examples of such techniques include particle systems (which can simulate rain, smoke, or fire), volumetric sampling (to simulate fog, dust and other spatial atmospheric effects), caustics (to simulate light focusing by uneven light-refracting surfaces, such as the light ripples seen on the bottom of a swimming pool), and subsurface scattering (to simulate light reflecting inside the volumes of solid objects such as human skin). The rendering process is computationally expensive, given the complex variety of physical processes being simulated. Computer processing power has increased rapidly over the years, allowing for a progressively higher degree of realistic rendering. Film studios that produce computer-generated animations typically make use of a render farm to generate images in a timely manner. However, falling hardware costs mean that it is entirely possible to create small amounts of 3D animation on a home computer system. The output of the renderer is often used as only one small part of a completed motionpicture scene. Many layers of material may be rendered separately and integrated into the final shot using compositing software.
Renderers Often renderers are included in 3D software packages, but there are some rendering systems that are used as plugins to popular 3D applications. These rendering systems include: • • • • • • • • •
AccuRender for SketchUp Brazil r/s Bunkspeed Final-Render Maxwell mental ray POV-Ray Realsoft 3D Pixar RenderMan
• • •
V-Ray YafRay Indigo Renderer.
Projection
Perspective Projection Since the human eye sees three dimensions, the mathematical model represented inside the computer must be transformed back so that the human eye can correlate the image to a realistic one. But the fact that the display device - namely a monitor - can display only two dimensions means that this mathematical model must be transferred to a twodimensional image. Often this is done using projection; mostly using perspective projection. The basic idea behind the perspective projection, which unsurprisingly is the way the human eye works, is that objects that are further away are smaller in relation to those that are closer to the eye. Thus, to collapse the third dimension onto a screen, a corresponding operation is carried out to remove it - in this case, a division operation. Orthogonal projection is used mainly in CAD or CAM applications where scientific modelling requires precise measurements and preservation of the third dimension.
Reflection and shading models Modern 3D computer graphics rely heavily on a simplified reflection model called Phong reflection model (not to be confused with Phong shading). In refraction of light, an important concept is the refractive index. In most 3D programming implementations, the term for this value is "index of refraction," usually abbreviated "IOR." Popular reflection rendering techniques in 3D computer graphics include:
• • • • • •
Flat shading: A technique that shades each polygon of an object based on the polygon's "normal" and the position and intensity of a light source. Gouraud shading: Invented by H. Gouraud in 1971, a fast and resource-conscious vertex shading technique used to simulate smoothly shaded surfaces. Texture mapping: A technique for simulating a large amount of surface detail by mapping images (textures) onto polygons. Phong shading: Invented by Bui Tuong Phong, used to simulate specular highlights and smooth shaded surfaces. Bump mapping: Invented by Jim Blinn, a normal-perturbation technique used to simulate wrinkled surfaces. Cel shading: A technique used to imitate the look of hand-drawn animation.
3D graphics APIs 3D graphics have become so popular, particularly in computer games, that specialized APIs (application programming interfaces) have been created to ease the processes in all stages of computer graphics generation. These APIs have also proved vital to computer graphics hardware manufacturers, as they provide a way for programmers to access the hardware in an abstract way, while still taking advantage of the special hardware of thisor-that graphics card. These APIs for 3D computer graphics are particularly popular: • • • • • • •
OpenGL and the OpenGL Shading Language OpenGL ES 3D API for embedded devices Direct3D (a subset of DirectX) RenderMan RenderWare Glide API TruDimension LC Glasses and 3D monitor API
There are also higher-level 3D scene-graph APIs which provide additional functionality on top of the lower-level rendering API. Such libraries under active development include: • • • • • • • • •
QSDK Quesa Java 3D JSR 184 (M3G) NVidia Scene Graph OpenSceneGraph OpenSG OGRE JMonkey Engine
• • •
Irrlicht Engine Hoops3D UGS DirectModel (aka JT)
3D computer graphics software
Modeling in LightWave. This interface is fairly typical of 3D packages. 3D computer graphics software refers to programs used to create 3D computergenerated imagery. There are typically many stages in the "pipeline" that studios use to create 3D objects for film and games, and this article only covers some of the software used. Note that most of the 3D packages have a very plugin-oriented architecture, and high-end plugins costing tens or hundreds of thousands of dollars are often used by studios. Larger studios usually create enormous amounts of proprietary software to run alongside these programs. If you are just getting started out in 3D, one of the major packages is usually sufficient to begin learning. Remember that 3D animation can be very difficult, time-consuming, and unintuitive; a teacher or a book will likely be necessary. Most of the high-end packages have free versions designed for personal learning.
Major packages 3ds Max (Autodesk), originally called 3D Studio MAX, is the leading animation program in the video game industry. Experts argue that it is very good at handling lowpolygon animation, but perhaps its greatest asset to the computer/video industry is its entrenched support network and its many plugins. It is also a more expensive high-end package, coming at US$3500, compared to about US$2000 for the others. Because of its presence in the video game industry, it is also a popular hobbyist package. 3ds Max is
also widely used in architectural visualizations because of its goes hand-in-hand very well with AutoCAD--also developed by Autodesk. Blender (Blender Foundation) is a modeling, rendering, and animation suite offering a feature set comparable to high end and mid range 3d animation suites such as Maya, 3ds Max, or Cinema 4D. It is being developed under the GPL and is available for free. Cinema 4D (MAXON) is a slightly lighter package than the others in its basic configuration. Its main asset is its artist-friendliness, avoiding the complicated technical nature of the other packages and its low entry cost because of the modular structure of its functions. For example, a popular module, BodyPaint, allows artists to draw textures directly onto the surface of models. It is also available for Mac OS X, Windows and Linux OS. form-Z (autodessys, Inc.) is a general purpose 3D modeler. Its primary usage is modeling, but also has limited rendering and animation capabilities. Many of its users are architects, but also include designers from many fields including interior designers, illustrators, product designers, and set designers. Its default renderer uses the LightWorks rendering engine for raytracing and radiosity. formZ has been around since 1991, available for both the Macintosh and Windows operating systems. The price is approximately $1495-$2390 depending on how much photorealistic rendering power is desired. Houdini (Side Effects Software) is a high-end package that is found often in studios. Its most common use is in animating special effects, rather than models. With a price tag of US$17,000, Houdini is the most expensive high-end 3D computer graphics package available. LightWave 3D (NewTek) is a popular 3D package because of its easy-to-learn interface; many artists prefer it to the more technical Maya or 3DS Max. It has weaker modeling and particularly animation features than some of the larger packages, but it is still used widely in film and broadcasting. (US $795) Maya (Autodesk) is currently the leading animation program for cinema; nearly every studio uses it. It is known as difficult to learn, but it is possibly the most powerful 3D package. When studios use Maya, they typically replace parts of it with proprietary software. Studios will also render using Pixar's Renderman, rather than the default
mentalray. Autodesk, makers of 3ds max, has recently acquired Alias--the original creator of Maya. Maya comes in two versions: Maya Complete (US$1999) and Maya Unlimited (US$6999) Modo (Luxology) is an advanced subdivision modeling, texturing and rendering tool. It has seen rapid adoption by 3D content creators in the movie and games industry due to its extremely powerful polygon modeling toolset. (895$) Silo (Nevercenter) is a subdivision-surface modeler available for Mac OS X and Windows, with a Linux OS version in development. Silo does not include a renderer and is priced accordingly ($109). Silo is the current recommended modeler for the Electric Image Animation System suite. SketchUp Pro (Google) is a 3D modelling package that has an innovate sketch based modeling approach (495$) Softimage|XSI (Avid) is often seen as head-to-head competition with Maya, and is very feature-similar. Fans of the two packages often will often argue the merits of each. The early Softimage 3D was once the leader in animation, but lagged as Maya surged ahead. The Newer Softimage XSI with more features and intergrated Mental Ray rendering is now trying to reclaim the top spot. TrueSpace (Caligari Corporation) is a feature-rich 3D package with modelling, animation, 3D-painting, and rendering capabilities for an affordable price. (from $199 for Version 5.2 to $595 for the latest Version 7) ZBrush (Pixologic) is a digital sculpting tool that combines 3D/2.5D modeling, texturing and painting tool available for Mac OS X and Windows. It is priced at 489$.
Other packages AC3D Animation:Master focuses on animation. It might be quicker and easier to learn and to use than the major packages. Bryce (DAZ productions) is most famous for landscapes.
Carrara (Eovia) is a 3D complete tool set package for 3D modeling, texturing animation and rendering; and Amapi and Hexagon (Eovia) are 3D packages often used for high-end abstract and organic modeling respectively. Daz Studio a specialized tool for adjusting parameters of preexisting models, posing and rendering them. Similar to Poser, but more limited in functionality. MilkShape 3D is a shareware/trialware polygon 3D modelling program with extensive import/export capabilities. Poser is specialized for adjusting features of preexisting models via varying parameters. It is also for posing and rendering of the models and characters. It includes some specialized tools for walk cycle creation, cloth and hair. Realsoft 3D Vue (e-on) is landscape generation software. Non-Commercial Anim8or is another free 3d rendering and animation package. Art of Illusion is another free software package developed under the GPL. DeleD 3D Editor is a fully functional game-oriented 3D Editor. PRO version also available. DIALux is light making software. It also makes buildings / architectural modeling and a little more. Used to cost thousands of dollars. It has renderers as well. Equinox-3D Landscape Studio is a Java-based heightmap generator. ShapeShop is a free sketch-based 3D modeling tool based on hierarchical implicit surfaces. Like Sketchup, it is very easy to use, but can create a much wider range of smooth surfaces. SharpConstruct is a free 3d modeling program that works like ZBrush.
Terragen and Terragen 2 is a freeware scenery generator. Wings 3D is a BSD-licensed, minimal modeler.
Renderers Pixar's RenderMan is the premier renderer, used in many studios. Animation packages such as 3DS Max and Maya can pipeline to RenderMan to do all the rendering. mental ray is another popular renderer, and comes default with most of the high-end packages. VRay is also a popular renderer--used primarily by those working in the architectural visualization field--for 3ds max and 3ds viz. POV-Ray and YafRay are two free renderers. Pixie is an open source photorealistic renderer. POV-Ray (or The Persistence of Vision Raytracer) is a freeware (with source) ray tracer written for multipule platforms. RPS Ray Trace and AccuRender for SketchUp add photorealistic rendering capabilities to SketchUp. Sunflow is an open source, photo-realistic renderer written in Java. YafRay (or Yet Another Free Raytracer) is an open source ray tracing program that utilizes XML for scene description. Recently it has been intergrated with Blender. Indigo Renderer is a closed source (but free for non and commercial use) photorealistic renderer that utilizes XML for scene description. Exporters available for Blender, Maya (Mti), Cinema4D, Rhino,3ds Max.
Related to 3D software Swift3D is a package for transforming models in Lightwave or 3DS Max into Flash animations. Match moving software is commonly used to match live video with computer-generated video, keeping the two in sync as the camera moves. Poser is the most popular program for modeling people. After producing video, studios then edit or composite the video using programs such as Adobe Premiere or Apple Final Cut at the low end, or Autodesk Combustion or Apple Shake at the high end.
Computer-generated imagery Computer-generated imagery (CGI) is the application of the field of computer graphics (or more specifically, 3D computer graphics) to special effects. CGI is used in films, television programs and commercials, and in printed media. Video games most often use real-time computer graphics (rarely referred to as CGI), but may also include prerendered "cut scenes" and intro movies that would be typical CGI applications. These are referred to as FMV. CGI is used for visual effects because the quality is often higher and effects are more controllable than other more physically based processes, such as constructing miniatures for effects shots or hiring extras for crowd scenes, and because it allows the creation of images that would not be feasible using any other technology. It can also allow a single artist to produce content without the use of actors, expensive set pieces, or props. Recent accessibility of CGI software and increased computer speeds has allowed individual artists and small companies to produce professional grade films, games, and fine art from their home computers. This has brought about an Internet subculture with its own set of global celebrities, clichés, and technical vocabulary. History
The pseudopod in The Abyss marked CGI's acceptance in the visual effects industry. 2D CGI was first used in movies in 1973's Westworld, though the first use of 3D imagery was in its sequel, Futureworld (1976), which featured a computer-generated hand and face created by then University of Utah graduate students Edwin Catmull and Fred Parke. The second movie to use this technology was Star Wars (1977) for the scenes with the Death Star plans. The first two films to make heavy investments in CGI, Tron (1982) and The Last Starfighter (1984), were commercial failures, causing most directors to relegate
CGI to images that were supposed to look like they were created by a computer. The first real CGI character was created by Pixar for the film Young Sherlock Holmes in 1985 (not counting the simple polyhedron character Bit in Tron). It took the form of a knight composed of elements from a stained glass window. Photorealistic CGI did not win over the motion picture industry until 1989, when The Abyss won the Academy Award for Visual Effects. Industrial Light and Magic (ILM) produced photorealistic CGI visual effects, most notably a seawater creature dubbed the pseudopod, featuring in one scene of the film. CGI then took a central role in Terminator 2: Judgment Day (1991), when the T-1000 Terminator villain wowed audiences with liquid metal and morphing effects fully integrated into action sequences throughout the film. Terminator 2 also won ILM an Oscar for its effects. It was the 1993 film Jurassic Park, however, where the dinosaurs appeared so life-like and the movie integrated CGI and live-action so flawlessly, that revolutionized the movie industry. It marked Hollywood’s transition from stop-motion animation and conventional optical effects to digital techniques. The following year, CGI was used to create the special effects for Forrest Gump. The most noteworthy effects shots were the digital removal of actor Gary Sinise's legs. Other effects included a napalm strike, fast-moving Ping-Pong balls and the feather in the title sequence. 2D CGI increasingly appeared in traditionally animated films, where it supplemented the use of hand-illustrated cels. Its uses ranged from digital tweening motion between frames, to eye-catching quasi-3D effects such as the ballroom scene in Beauty and the Beast.
Toy Story (1995) was the first fully computer-generated feature film. In 1995, the first fully computer-generated feature film, Pixar's (The Walt Disney Company) Toy Story, was a resounding commercial success. Additional digital animation studios such as Blue Sky Studios (Fox), DNA Productions (Paramount Pictures and Warner Bros.), Onation Studios (Paramount Pictures), Sony Pictures Animation (Columbia Pictures), Vanguard Animation (Walt Disney Pictures, Lions Gate Films and 20th Century Fox), Big Idea Productions (Universal Pictures and FHE Pictures) and Pacific Data Images (Dreamworks SKG) went into production, and existing animation companies such as The Walt Disney Company began to make a transition from traditional animation to CGI. Between 1995 and 2005 the average effects budget for a wide-release feature film skyrocketed from $5 million to $40 million. According to one studio executive, as of 2005, more than half of feature films have significant effects. In the early 2000s, computer-generated imagery became the dominant form of special effects. The technology progressed to the point that it became possible to include virtual stunt doubles that were nearly indistinguishable from the actors they replaced. Camera tracking software was refined to allow increasingly complex visual effects developments that were previously impossible. Computer-generated extras also became used extensively in crowd scenes with advanced flocking and crowd simulation software. The timeline of CGI in movies shows a detailed list of pioneering uses of computer-generated imagery in film and television.
CGI for films is usually rendered at about 1.4–6 megapixels. Toy Story, for example, was rendered at 1536 × 922 (1.42MP). The time to render one frame is typically around 2–3 hours, with ten times that for the most complex scenes. This time hasn't changed much in the last decade, as image quality has progressed at the same rate as improvements in hardware, since with faster machines, more and more complexity becomes feasible. Exponential increases in GPUs processing power, as well as massive increases in parallel CPU power, storage and memory speed and size have greatly increased CGI's potential.
Final Fantasy: The Spirits Within (2001) was the first attempt to create a life-like feature film using only CGI. In 2001, Square Pictures created the CGI film Final Fantasy: The Spirits Within, which featured highly detailed and photographic-quality graphics. The film was not a box-office success. Some commentators have suggested this may be partly because the lead CGI characters had facial features which fell into the uncanny valley. After creating one more film using a similar visual style (Final Flight of the Osiris, a short film which served as a prologue to The Matrix Reloaded), Square Pictures closed down. However, as the newly-merged SquareEnix, they released another purely-CGI-done film in fall 2006 titled Final Fantasy VII: Advent Children. It has been since credited as a breakthrough in CGI performance Developments in CGI technologies are reported each year at SIGGRAPH, an annual conference on computer graphics and interactive techniques, attended each year by tens of thousands of computer professionals. Developers of computer games and 3D video cards strive to achieve the same visual quality on personal computers in real-time as is possible for CGI films and animation. With the rapid advancement of real-time rendering quality, artists began to use game engines to render non-interactive movies. This art form is called machinima.
Creating characters and objects on a computer
The character Gollum from The Lord of the Rings film trilogy was composed entirely of CGI along with the use of motion capture. 3D computer animation combines 3D modeling with programmed movement. Models are constructed out of geometrical vertices, faces, and edges in a true 3D coordinate system. Objects are sculpted much like real clay or plaster, working from general forms to specific details with various sculpting tools. A bone/joint system is set up to deform the 3d mesh ie. to make a humanoid model walk. In a process called rigging, the virtual marionette is given various controllers and handles for an animator to manipulate. The character "Woody" in Pixar's movie Toy Story, for example, uses 700 specialized animation controllers. In the 2004 film The Day After Tomorrow, designers had to completely create forces of extreme weather with only the help of video references and accurate meteorological fact. For the 2005 remake of King Kong, actor Andy Serkis was used to help designers pinpoint the gorilla's prime location in the shots and used his expressions to model "human" characteristics onto the creature.
Digital Grading One of the less obvious CGI effects in movies is digital grading. This is a computer process in which sections of the original image are color corrected using special processing software. A detail that was too dark in the original shot can be lit and enhanced in this post-production process. For example, in Star Trek: First Contact, digital grading was used to turn Picard's face blue as his Borg assimilation is shown, and in The Lord of the Rings digital grading was used to drain the color from Sean Bean's face as his character died.
Special effect
Lasers were used in the 2005 Classical Spectacular concert Special effects (abbreviated SPFX or SFX) are used in the film, television, and entertainment industry to realize scenes that cannot be achieved by normal means, such as space travel. They are also used when creating the effect by normal means is prohibitively expensive; for example, it would be extremely expensive to construct a 16th century castle or to sink a 20th century ocean liner, but these can be simulated with special effects. With the advent of computer graphics imaging, special effects are also used to enhance previously filmed elements, by adding, removing or enhancing objects within the scene. Many different special effects techniques exist, ranging from traditional theater effects or elaborately staged as in the "machine plays" of the Restoration spectacular, through classic film techniques invented in the early 20th century, such as aerial image photography and optical printers, to modern computer graphics imagery (CGI). Often several different techniques are used together in a single scene or shot to achieve the desired effect. Generally, special effects are traditionally divided into two types. The first is optical effects (also called visual or photographic effects), which rely on manipulation of a photographed image. Optical effects can be produced with either photographic (i.e. optical printer) or visual (i.e. CGI) technology. A good example of an optical effect would be a scene in Star Trek depicting the USS Enterprise flying through space. The second type is mechanical effects (also called practical or physical effects), which are accomplished during the live-action shooting. These include mechanized props, scenery, and pyrotechnics. Good examples would be the ejector seat of James Bond's
Aston Martin, R2D2 in the Star Wars films, or the zero-gravity effects employed in 2001: A Space Odyssey.
Developmental history In 1895, Alfred Clarke created what is commonly accepted as the first-ever special effect. While filming a reenactment of the beheading of Mary, Queen of Scots, Clarke instructed an actor to step up to the block in Mary's costume. As the executioner brought the axe above his head, Clarke stopped the camera, had all of the actors freeze, and had the person playing Mary step off the set. He placed a Mary dummy in the actor's place, restarted filming, and allowed the executioner to bring the axe down, severing the dummy's head. “Such… techniques would remain at the heart of special effects production for the next century” (Rickitt, 10). This was not only the first use of trickery in the cinema. It was the first development of trickery that could only be done in a motion picture, i.e., the "stop trick." In 1896, French magician Georges Melies accidentally discovered the same "stop trick." According to Melies, his camera jammed while filming a street scene in Paris. When he screened the film, he found that the "stop trick" had caused a truck to turn into a hearse, pedestrians to change direction, and men turn into women. Melies, the stage manager at the Theatre Robert-Houdin, was inspired to develop a series of more than 500 short films, between 1896 and 1914, in the process developing or inventing such techniques as multiple exposures, time-lapse photography, dissolves, and hand-painted colour. Because of his ability to seemingly manipulate and transform reality with the cinematograph, the prolific Méliès is sometimes referred to as the "Cinemagician." During the 1920's and 1930's, special effects techniques were improved and refined by the motion picture industry. Many techniques were modifications of illusions from the theater (such as Pepper's Ghost) and still photography (such as double exposure and matte compositing). Rear projection was a refinement of the use of painted backgrounds in the theater – only substituting moving pictures to create moving backgrounds. But several techniques soon developed that, like the "stop trick," were wholly original to motion pictures. Animation creates the illusion of motion, and was quickly accomplished with drawings (most notably by Winsor McCay in Gertie the Dinosaur) and with threedimensional models (most notably by Willis O'Brien in The Lost World and King Kong).
Also, the challenge of simulating spectacle in motion encouraged to develop considerable skill in the use of miniatures. Naval battles could be depicted with models in studio tanks, and airplanes could be flown (and crashed) without risk of life and limb. Most impressively, miniatures and matte paintings could be used to depict worlds that never existed, such as the massive city of Fritz Lang's film Metropolis. One of the greatest innovations in special-effects photography was the development of the optical printer. Essentially, an optical printer is a projector aiming into a camera lens, and it was developed to make copies of films for distribution. Until its refinement by Linwood Dunn, effects shots were accomplished as an in-camera effect, but Dunn expanded on the device, demonstrating that it could be used to combine images in novel ways and create new illusions. One early showcase for Dunn was Orson Welles' Citizen Kane, where such locations as Xanadu (and some of Gregg Toland's famous 'deep focus' shots) were essentially created by Dunn's optical printer. As the industry progressed, special effects techniques kept pace. The development of color photography required greater refinement of effects techniques. Also, color enabled the development of such travelling matte techniques as bluescreen and the sodium vapor process. Many films include landmark scenes in special-effects accomplishments: Forbidden Planet used matte paintings, animation, and miniature work to create spectacular alien worlds. In The Ten Commandments, Paramount's John P. Fulton multiplied the crowds of extras in the Exodus scenes, depicted the massive constructions of Rameses, and split the Red Sea in a still-impressive combination of travelling mattes and water tanks. If one film could be said to have established the high-water mark for special effects, it would be 1968's 2001:A Space Odyssey, directed by Stanley Kubrick. In this film, the spaceship miniatures were highly detailed and carefully photographed for a realistic depth of field. The shots of spaceships were combined through hand-drawn rotocscopes and careful motion-control work, ensuring that the elements were combined in the camera-- a surprising throwback to the silent era, but with spectacular results. Backgrounds of the African vistas in the Dawn of Man sequence were created with the then-new front projection technique. The finale, a voyage through hallucinogenic scenery, was created by Douglas Trumbull using a new technique termed slit-scan. Even today, the effects scenes remain impressive, realistic, and awe-inspiring.
1977 was a watershed year in the special effects industry, because of two blockbuster films. George Lucas's film Star Wars ushered in an era of fantasy films with expensive and impressive special-effects. Effects supervisor John Dykstra and crew developed many improvements in existing effects technology. They developed a computercontrolled camera called the "Dykstraflex" that allowed precise repeatability of camera motion. This greatly facilitated travelling matte compositing. Degradation of film images after compositing was minimized by other innovations: the Dykstraflex used VistaVision cameras that photographed widescreen images horizontally along 35mm film stock, using far more of the film per frame, and thinner-emulsion filmstocks were used in the compositing process. That same year, Steven Spielberg's film Close Encounters of the Third Kind boasted a finale with impressive special effects by 2001 veteran Douglas Trumbull. In addition to developing his own motion-control system, Trumbull also developed techniques for creating intentional "lens flare" (the shapes created by light reflecting in camera lenses) to create undefinable shapes of flying saucers. These two films reflected a new sensibility among special effects technicians. Previously, studios were content to use the old techniques to achieve serviceable illusions. But a generation of technicians who weren't fooled by the old techniques now had the means (i.e., massive studio investment in effects-heavy films) to improve every tool in the special effects arsenal. Lucas, after the success of Star Wars, founded an innovative effects house called Industrial Light and Magic which has spearheaded most effects innovations over the last few decades. The single greatest innovation was the development of computer generated imagery (CGI). Although it had been used to striking effect in such films as Young Sherlock Holmes, its most impressive early use has come in films by James Cameron (The Abyss, Terminator 2: Judgement Day). In 1993 Steven Spielberg's Jurassic Park used CGI to create realistic dinosaurs-- an indication that many of the older effects techniques would be changed radically if not rendered obsolete. Stop-motion animators working on the film were quickly retrained in the use of computer input devices. Digital compositing avoided the inherent graininess of optical compositing. Digital imagery enabled technicians to create detailed matte "paintings," miniatures, and even crowds of computer-generated people.
By 1995, films such as Toy Story underscored that the distinction between live-action films and animated films was no longer clear. Images could be created in a computer, using the techniques of animated cartoons. It is now possible to create any image and have it look completely realistic to an audience.
Special Effects Animation Also known as effects animation, special effects animation is a specialization of the traditional animation and computer animation processes. Anything that moves in an animated film and is not a character (handled by character animators) is considered a special effect, and is left up to the special effects animators to create. Effects animation tasks can include animating cars, trains, rain, snow, fire, magic, shadows, or other noncharacter entities, objects, and phenomena. A classic case of this would be the lightsabres and laser-bolts in the original Star Wars, or the Monster from the ID from Forbidden Planet, both of which were created by rotoscopy. Sometimes, special processes are used to produce effects animation instead of drawing or rendering. Rain, for example, has been created in Walt Disney Feature Animation/Disney films since the late-1930s by filming slow-motion footage of water in front of a black background, with the resulting film superimposed over the animation. Among the most notable effects animators in history are A.C. Gamer from Termite Terrace/Warner Bros.; and Joshua Meador, Cy Young, Mark Dindal, and Randy Fullmer from the Walt Disney animation studio. Special effects animation is also common in live-action films to create certain images that cannot be traditionally filmed. In that respect, special effects animation is more commonplace than character animation, since special effects of many different types and varieties have been used in film for a century.
Visual special effects techniques in rough order of invention • • • • •
practical effects in-camera effects miniature effects Schüfftan process matte paintings
Rick Baker John Blakeley Ben Bornstein John Dykstra Richard Edlund John P. Fulton John Gaeta Ray Harryhausen Evan Jacobs Dennis Muren Derek Meddings Georges Melies Ken Ralston Tom Savini Eugen Schüfftan Colin Strause Greg Strause Phil Tippett Douglas Trumbull Eiji Tsuburaya Matthew Yuricich Hamid Haguouche L.B. Abbott Adam Savage Jamie Hyneman
CGI and SFX Effects that are created via computers, or during editing are known as CGI (Computer generated Imagery) effects and they fit into the category of optical effects - a subset of SFX - because they involve altering a photographic image. Some people claim that because CGI effects are not produced during filiming on-set (as in bullet hits, fire, flame, and explosions, wind, rain, etc.) that they are not SFX at all. However, as discussed above in the introduction to this article, effects produced during filming on-set are a different subset of SFX known as mechanical effects. CGI effects, while not mechanical in nature, still fit into the category of SFX.
Landmark movies • • • • • • • • • • • • • • •
The Lord of the Rings Trilogy (Created Massive Software, prosthetic work, digital effects) The Day After Tomorrow (prolonged digital shots, playing with "weather effects") Star Wars (Creation of original, practical effects) Tron (Digital Animation) The Terminator (digital effects) Terminator 2 (3-Dimensional Morphing and 3D Human Body) Independence Day (Digital effects combined with small-scale models) Jurassic Park (Large animatronics, creating creatures from scratch) Amadeus (Old age stipple, era effects) The Birds (Male/Female Matte developments) Titanic (Model work, scaling water) Toy Story (Complete Computer Animation) Buddy (Anamatronics) The Matrix Trilogy (Bullet Time) King Kong (2005) (Motion Capture)
Motion capture Motion capture, Motion Tracking or Mocap, is a technique of digitally recording movements for entertainment, sports and medical applications.
Methods and Systems Motion tracking or motion capture started as an analysis tool in biomechanics research, and expanded into education, training, sports and recently computer animation for cinema and video games as the technology has matured. A performer wears markers near each joint to identify the motion by the positions or angles between the markers. Acoustic, inertial, LED, magnetic or reflective markers, or combinations of any of these, are tracked, optimally at least two times the rate of the desired motion, to submillimeter positions. The motion capture computer software records the positions, angles, velocities, accelerations and impulses, providing an accurate digital representation of the motion. In entertainment applications this can reduce the costs of animation which otherwise requires the animator to draw each frame, or with more sophisticated software, key frames which are interpolated by the software. Motion capture saves time and creates more natural movements than manual animation, but is limited to motions that are anatomically possible. Some applications might require additional impossible movements like animated super hero martial arts or stretching and squishing that are not possible with real actors. In biomechanics, sports and training, real time data can provide the necessary information to diagnose problems or suggest ways to improve performance, driving ever faster motion capture technology. Optical systems triangulate the 3D position of a marker between one or more cameras calibrated to provide overlapping projections. Tracking a large number of markers or multiple performers or expanding the capture area is accomplished by the addition of more cameras. These systems produce data with 3 degrees of freedom for each marker, and rotational information must be inferred from the relative orientation of three or more markers; for instance shoulder, elbow and wrist markers providing the angle of the elbow. A newer technique discussed below uses higher resolution linear detectors to derive the one dimensional positions, requiring more sensors and more computations, but
providing higher resolutions (sub millimeter down to 10 micrometers time averaged) and speeds than possible using area arrays.
A dancer wearing a suit used in an optical motion capture system Passive optical systems use reflective markers illuminated from strobes on the camera and triangulate each marker from its relative location on a 2D map. Data can be cleaned up with the aid of kinematic constraints and predictive gap filling algorithms. Passive systems typically use sensors where the camera captures an image of the scene, reduces it to bright spots and finds the centroid. These 1.3 megapixel sensors can run at frame rates up to 60,000,000 pixels per second divided by the resolution, so at 1.3 megapixels they can operate at 500 frames per second. A high speed 4 megapixel sensor costs around $1,000 USD and can run at 640,000,000 pixels per second divided by the applied resolution. By decreasing the resolution down to 640 x 480, these cameras can sample at 2,000 frames per second, but then trade off spatial resolution for temporal resolution. At full resolution they run about 166 frames per second, but typically are run at 100 to 120 frames per second. A $100, low speed 4 megapixel detector has a bandwidth of about 40,000,000 pixels per second and is unsuitable for motion capture. With about 200 LED strobes syncronized to the CMOS sensor, the ease of combining a hundred dollars worth of LEDs to a $1,000 sensor has made these systems very popular. Professional vendors have sophisticated software to reduce problems from marker swapping since all markers appear identical. Unlike active marker systems and magnetic systems, passive systems do not require the user to wear wires or electronic equipment. Passive markers are usually spheres or hemispheres made of plastic or foam 25 to 3mm in diameter with special retroreflective tape. This type of system can capture large numbers of markers at frame rates as high as 2000fps and high 3D accuracy.
Active marker systems have an advantage over passive in that there is no doubt about which marker is which. In general, the overall update rate drops as the marker count increases; 5000 frames per second divided by 100 markers would provide updates of 50 hertz. As a result, these systems are popular in the biomechanics market.
A high-resolution active marker system with 3,600 × 3,600 resolution at 480 hertz providing real time submillimeter positions. Higher resolution active marker systems show more subtle movements by providing marker IDs in real time, modulating the output of the LED to differentiate each marker, allowing 32 markers to be on at the same time, eliminating marker swapping and providing much cleaner data than older technologies. Smart LEDs allow motion capture outdoors in direct sunlight, while providing the 3,600 × 3,600 or 12 megapixel resolution while capturing at 480 frames per second. The advantage of using active markers is intelligent processing allows higher speed and higher resolution of optical systems at a lower price. This higher accuracy and resolution requires more processing than older passive technologies, but the additional processing is done at the camera to improve resolution via a subpixel or centroid processing, providing both high resolution and high speed. By using newer processing and technology, these motion capture systems are about 1/3 the cost of older systems. Magnetic systems calculate position and orientation by the relative magnetic flux of three orthogonal coils on both the transmitter and each receiver. The relative intensity of the voltage or current of the three coils allows these systems to calculate both range and orientation by meticulously mapping the tracking volume. Since the sensor output is
6DOF, useful results can be obtained with two-thirds the number of markers required in optical systems; one on upper arm and one on lower arm for elbow position and angle. The markers are not occluded by nonmetallic objects but are susceptible to magnetic and electrical interference from metal objects in the environment, like rebar (steel reinforcing bars in concrete) or wiring, which affect the magnetic field, and electrical sources such as monitors, lights, cables and computers. The sensor response is nonlinear, epecially toward edges of the capture area. The wiring from the sensors tends to preclude extreme performance movements. The capture volumes for magnetic systems are dramatically smaller than they are for optical systems. With the magnetic systems, there is a distinction between “AC” and “DC” systems: one uses square pulses, the other uses sine wave pulses. Mechanical motion capture systems directly track body joint angles and are often referred to as exo-skeleton motion capture systems, due to the way the sensors are attached to the body. A performer attaches the skeletal-like structure to their body and as they move so do the articulated mechanical parts, measuring the performer’s relative motion. Mechanical motion capture systems are real-time, relatively low-cost, free-of-occlusion, and wireless (untethered) systems that have unlimited capture volume. Typically, they are rigid structures of jointed, straight metal or plastic rods linked together with potentiometers that articulate at the joints of the body.
The procedure In the motion capture session, the movements of one or more actors are sampled many times per second. High resolution optical motion capture systems can be used to sample body, facial and finger movement at the same time. A motion capture session records only the movements of the actor, not his visual appearance. These movements are recorded as animation data which are mapped to a 3D model (human, giant robot, etc.) created by a computer artist, to move the model the same way. This is comparable to the older technique of rotoscope where the visual appearance of the motion of an actor was filmed, then the film used as a guide for the frame by frame motion of a hand-drawn animated character. If desired, a camera can pan, tilt, or dolly around the stage while the actor is performing and the motion capture system can capture the camera and props as well. This allows the
computer generated characters, images and sets, to have the same perspective as the video images from the camera. A computer processes the data and displays the movements of the actor, as inferred from the 3D position of each marker. If desired, a virtual or real camera can be tracked as well, providing the desired camera positions in terms of objects in the set. A related technique match moving can derive 3D camera movement from a single 2D image sequence without the use of photogrammetry, but is often ambiguous below centimeter resolution, due to the inability to distinguish pose and scale characteristics from a single vantage point. One might extrapolate that future technology might include full-frame imaging from many camera angles to record the exact position of every part of the actor’s body, clothing, and hair for the entire duration of the session, resulting in a higher resolution of detail than is possible today. After processing, the software exports animation data, which computer animators can associate with a 3D model and then manipulate using normal computer animation software. If the actor’s performance was good and the software processing was accurate, this manipulation is limited to placing the actor in the scene that the animator has created and controlling the 3D model’s interaction with objects.
Advantages Mocap offers several advantages over traditional computer animation of a 3D model: • •
•
Mocap can take far fewer man-hours of work to animate a character. One actor working for a day (and then technical staff working for many days * Mocap can capture secondary animation that traditional animators might not have had the skill, vision, or time to create. For example, a slight movement of the hip by the actor might cause his head to twist slightly. This nuance might be understood by a traditional animator but be too time consuming and difficult to accurately represent, but it is captured accurately by mocap, which is why mocap animation often seems shockingly realistic compared with hand animated models. Incidentally, one of the hallmarks of rotoscope in traditional animation is just such secondary “business.” Using Mocap, animators can capture subtleties that a traditional animator could never conceive. One such detail is seen when a ball bounces. Mocap can capture how the ball actually squashes as it makes contact with the ground and stretches as it accelerates upward off the surface. This basic underlying movement can be seen in human actions and now accurately captured using Mocap in places where drawn animation was unable to accurately portray such "squash and stretch."
•
•
Mocap can accurately capture difficult-to-model physical movement. For example, if the mocap actor does a backflip while holding nunchaku by the chain, both sticks of the nunchucks will be captured by the cameras moving in a realistic fashion. A traditional animator might not be able to physically simulate the movement of the sticks adequately due to other motions by the actor. Secondary motion such as the ripple of a body as an actor is punched or is punching requires both higher speed and higher resolution as well as more markers. Mocap technology allows studios to hand pick one actor to play multiple roles within a single film.
Disadvantages On the negative side, mocap data requires special programs and time to manipulate once captured and processed, and if the data is wrong, it is often easier to throw it away and reshoot the scene rather than trying to manipulate the data. Many systems allow real time viewing of the data to decide if the take needs to be redone. Another important point is that while it is common and comparatively easy to mocap a human actor in order to animate a biped model, applying motion capture to animals like horses can be difficult. Motion capture equipment costs hundreds of thousands of dollars (if not millions in some cases) for the digital video cameras, lights, software, and staff to run a mocap studio, and this technology investment can become obsolete every few years as better software and techniques are invented. Some large movie studios and video game publishers have established their own dedicated mocap studios, but most mocap work is contracted to individual companies that specialize in mocap. Computer models that have a cartoony design will "break" when realistic human movement is applied to them. For example, if a cartoony character has large, over-sized hands, these will intersect strangely with any other body part when the human actor brings them too close to his body. Although motion capture produces "realistic" movement, hand animation often allows for stronger applications of traditional techniques like squash and stretch, secondary motion, and anticipation, creating characters with greater impact and personality.
Applications
Video games use motion capture for football, baseball and basketball players or the combat moves of a martial artist. Movies use motion capture for CG effects, in some cases replacing traditional cell animation, and for completely computer-generated creatures, such as Gollum, Jar-Jar Binks, and King Kong. Virtual Reality and Augmented Reality require real time input of the user’s position and interaction with their environment, requiring more precision and speed than older motion capture systems could provide. Noise and errors from low resolution or low speed systems, and overly smoothed and filtered data with long latency contribute to “simulator sickness” where the lag and mismatch between visual and vistibular cues and computer generated images caused nasea and discomfort. High speed—high resolution active marker systems can provide smooth data at low latency, allowing real time visualization in virtual and augmented reality systems. The remaining challenge that is almost possible with powerful graphic cards is mapping the images correctly to the real perspectives to prevent image mismatch. Motion capture technology is frequently used in digital puppetry systems to aid in the performance of computer generated characters in real-time.
Related techniques Facial motion capture is utilized to record the complex movements in a human face, especially while speaking with emotion. This is generally performed with an optical setup using multiple cameras arranged in a hemisphere at close range, with small markers glued or taped to the actor’s face. Performance capture is a further development of these techniques, where both body motions and facial movements are recorded. This technique was used in making of The Polar Express. Inertial systems use devices such as accelerometers or gyroscopes to measure positions and angles. They are often used in conjunction with other systems to provide updates and global reference, since they only measure relative changes, not absolute position.
RF (radio frequency) positioning systems are becoming more viable as higher frequency RF devices allow greater precision than older RF technologies. The speed of light is 30 centimeters per nanosecond (billionth of a second), so a 10 gigahertz (billion cycles per second) RF signal enables an accuracy of about 3 centimeters. By measuring amplitude to a quarter wavelength, it is possible to improve the resolution down to about 8 mm. To achieve the resolution of optical systems, frequencies of 50 gigahertz or higher are needed, which are almost as line of sight and as easy to block as optical systems. Multipath and reradiation of the signal are likely to cause additional problems, but these technologies will be ideal for tracking larger volumes with reasonable accuracy, since the required resolution at 100 meter distances isn’t likely to be as high. An alternative approach was developed where the actor is given an unlimited walking area through the use of a rotating sphere, similar to a hamster ball, which contains internal sensors recording the angular movements, removing the need for external cameras and other equipment. Even though this technology could potentially lead to much lower costs for mocap, the basic sphere is only capable of recording a single continuous direction. Additional sensors worn on the person would be needed to record anything more.
Rotoscope Rotoscoping is a technique where animators trace live action movement, frame by frame, for use in animated films. Originally, pre-recorded live-film images were projected onto a frosted glass panel and redrawn by an animator. This projection equipment is called a Rotoscope.
History
Patent drawing for Fleischer's original rotoscope. The artist is drawing on a transparent easel, onto which the movie projector at the right is throwing an image of a single film frame. The technique was invented by Max Fleischer, who used it in his series "Out of the Inkwell" starting around 1914, with his brother Dave Fleischer dressed in a clown outfit as the live-film reference for the character Koko the Clown. Fleischer used rotoscope in a number of his later cartoons as well, most notably the Cab Calloway dance routines in three Betty Boop cartoons from the early 1930s, and the animation of Gulliver in Gulliver's Travels. Walt Disney and his animators employed it carefully and very effectively in Snow White and the Seven Dwarfs in 1937. Rotoscoping was also used in many of Disney's subsequent animated feature films with human characters, such as Cinderella in 1950. Later, when Disney animation became more stylized (e.g. "One Hundred and One Dalmatians, 1961), the rotoscope was used mainly for studying human and animal motion, rather than actual tracing.
Ralph Bakshi used the technique quite extensively in his animated movies Wizards (1977), The Lord of the Rings (1978), American Pop (1981), and Fire and Ice (1983). Bakshi first turned to rotoscoping because he was refused by 20th Century Fox for a $50,000 budget increase to finish Wizards, and thus had to resort to the rotoscope technique to finish the battle sequences. (This was the same meeting at which George Lucas was also denied a $3 million budget increase to finish Star Wars.) Rotoscoping was also used in Heavy Metal, the 1985 A-ha music video Take on Me, and Don Bluth's Titan A.E.. While rotoscoping is generally known to bring a sense of realism to larger budget animated films, the American animation company Filmation, known for its budgetcutting limited TV animation, was also notable for its heavy usage of rotoscope to good effect in series such as Flash Gordon, Blackstar and He-Man and the Masters of the Universe. Smoking Car Productions invented a digital rotoscoping process in 1994 for the creation of its critically-acclaimed adventure game The Last Express. The process was awarded U.S. Patent 6061462: Digital Cartoon and Animation Process. Using a similar technique, Richard Linklater produced a digitally rotoscoped feature called Waking Life, creating a surreal image of live action footage, a technique which he also used in the production of the film A Scanner Darkly. Linklater licensed the same proprietary rotoscoping process for the look of both films. Linklater is the first director to use digital rotoscoping to create an entire feature film. Additionally, a 2005-06 advertising campaign by Charles Schwab uses rotoscoping for a series of television spots, under the tagline "Talk to Chuck." This distinctive look is the work of Bob Sabiston, an MIT Media Lab veteran who brought the same "interpolated rotoscoping" technique to the Richard Linklater films Waking Life and A Scanner Darkly.
Technique
A horse animated by rotoscoping from Edweard Muybridge's 19th century photos. Rotoscoping is decried by some animation purists but has often been used to good effect. When used as an animator's reference tool, it can be a valuable time-saver. Rotoscope output can have slight deviations from the true line that differ from frame to frame, which when animated cause the animated line to "boil". Avoiding boiling requires considerable skill in the person performing the tracing, though causing the "boil" intentionally is a stylistic technique sometimes used to emphasize the surreal quality of rotoscoping, as in the music video Take on Me. Rotoscoping has often been used as a tool for special effects in live action movies. By tracing an object, a silhouette (called a matte) can be created that can be used to create an empty space in a background scene. This allows the object to be placed in the scene. However, this technique has been largely superseded by bluescreen techniques. Rotoscoping has also been used to allow a special visual effect (such as a glow, for example) to be guided by the matte or rotoscoped line. One classic use of traditional rotoscoping was in the original three Star Wars films, where it was used to create the glowing lightsaber effect, by creating a matte based on sticks held by the actors. The term "rotoscoping" (typically abbreviated as "roto") is now generally used for the corresponding all-digital process of tracing outlines over digital film images to produce digital mattes. This technique is still in wide use for special cases where techniques such as bluescreen will not pull an accurate enough matte. Rotoscoping in the digital domain is often aided by motion tracking and onion-skinning software. Rotoscoping is often used in the preparation of garbage mattes for other matte-pulling processes.
Examples of rotoscoping in animated films:
• • • • • • • • • •
Snow White (1933 cartoon) Snow White and the Seven Dwarfs The 1940s Superman cartoons Yellow Submarine The Lord of the Rings (1978) American Pop Titan A.E. Kid's Story (The Animatrix short) Waking Life A Scanner Darkly
in live action films: • • • • • •
The Good, the Bad and the Ugly (title sequence) Star Wars Tron (combination of computer animation and live action) Who Framed Roger Rabbit (combination of traditional animation and live action) Kill Bill Vol. 1 (Chapter Three: The Origin of O-Ren uses a combination of rotoscoping and traditional animation) Harry and the Hendersons (Certain scenes from the movie are rotoscoped for the end credits.)
in video games: • • • • • • • •
Commander Blood The Last Express Prince of Persia Karateka Another World Flashback: The Quest for Identity Joy Mecha Fight Blackthorne
in music videos: • • • • • • • •
Take on Me by a-ha Money for Nothing by Dire Straits Breaking the Habit by Linkin Park Frontline by Pillar Destiny by Zero 7 Frijolero by Molotov Drive by Incubus Go With the Flow by Queens of the Stone Age
in television shows:
• • • •
Delta State Flash Gordon (Filmation 1978) Blackstar (Filmation 1980) He-Man and the Masters of the Universe (Filmation 1983-1985)
in commercials •
Charles Schwabb commercial
Computer representation of surfaces
An open surface with u- and v-flow lines and Z-contours shown. In technical applications of 3D computer graphics (CAx) such as computer-aided design and computer-aided manufacturing, surfaces are one way of representing objects. The other ways are wireframe (lines and curves) and solids. Point clouds are also sometimes used as temporary ways to represent an object, with the goal of using the points to create one or more of the three permanent representations.
Open and closed surfaces If one considers a local parametrization of a surface:
then the curves obtained by varying u while keeping v fixed are sometimes called the u flow lines. The curves obtained by varying v while u is fixed are called the v flow lines. These are generalizations of the x and y lines in the plane and of the meridians and circles of latitude on a sphere. Open surfaces are not closed in either direction. This means moving in any direction along the surface will cause an observer to hit the edge of the surface. The top of a car hood is an example of a surface open in both directions.
Surfaces closed in one direction include a cylinder, cone, and hemisphere. Depending on the direction of travel, an observer on the surface may hit a boundary on such a surface or travel forever. Surfaces closed in both directions include a sphere and a torus. Moving in any direction on such surfaces will cause the observer to travel forever without hitting an edge. Places where two boundaries overlap (except at a point) are called a seam. For example, if one imagines a cylinder made from a sheet of paper rolled up and taped together at the edges, the boundaries where it is taped together are called the seam.
Flattening a surface Some open surfaces and surfaces closed in one direction may be flattened into a plane without deformation of the surface. For example, a cylinder can be flattened into a rectangular area without distorting the surface distance between surface features (except for those distances across the split created by opening up the cylinder). A cone may also be so flattened. Such surfaces are linear in one direction and curved in the other (surfaces linear in both directions were flat to begin with). Sheet metal surfaces which have flat patterns can be manufactured by stamping a flat version, then bending them into the proper shape, such as with rollers. This is a relatively inexpensive process. Other open surfaces and surfaces closed in one direction, and all surfaces closed in both directions, can't be flattened without deformation. A hemisphere or sphere, for example, can't. Such surfaces are curved in both directions. This is why maps of the Earth are distorted. The larger the area the map represents, the greater the distortion. Sheet metal surfaces which lack a flat pattern must be manufactured by stamping using 3D dies (sometimes requiring multiple dies with different draw depths and/or draw directions), which tend to be more expensive.
Surface patches A surface may be composed of one or more patches, where each patch has its own U-V coordinate system. These surface patches are analogous to the multiple polynomial arcs used to build a spline. They allow more complex surfaces to be represented by a series of relatively simple equation sets rather than a single set of complex equations. Thus, the
complexity of operations such as surface intersections can be reduced to a series of patch intersections. Surfaces closed in one or two directions frequently must also be broken into two or more surface patches by the software.
Faces Surfaces and surface patches can only be trimmed at U and V flow lines. To overcome this severe limitation, surface faces allow a surface to be limited to a series of boundaries projected onto the surface in any orientation, so long as those boundaries are collectively closed. For example, trimming a cylinder at an angle would require such a surface face. A single surface face may span multiple surface patches on a single surface, but can't span multiple surfaces. Planar faces are similar to surface faces, but are limited by a collectively closed series of boundaries projected to an infinite plane, instead of a surface.
Skins and volumes As with surfaces, surface faces closed in one or two directions frequently must also be broken into two or more surface faces by the software. To combine them back into a single entity, a skin or volume is created. A skin is an open collection of faces and a volume is a closed set. The constituent faces may have the same support surface or face or may have different supports.
Transition to solids Volumes can be filled in to build a solid model (possibly with other volumes subtracted from the interior). Skins and faces can also be offset to create solids of uniform thickness.
Types of continuity A surface's patches and the faces built on that surface typically have point continuity (no gaps) and tangent continuity (no sharp angles). Curvature continuity (no sharp radius changes) may or may not be maintained.
Skins and volumes, however, typically only have point continuity. Sharp angles between faces built on different supports (planes or surfaces) are common.
Surface visualization / display Surfaces may be displayed in many ways: •
Wireframe mode. In this representation the surface is drawn as a series of lines and curves, without hidden line removal. The boundaries and flow lines (isoparametric curves) may each be shown as solid or dashed curves. The advantage of this representation is that a great deal of geometry may be displayed and rotated on the screen with no delay needed for graphics processing.
wireframe hidden edges
wireframe uv isolines
•
Faceted mode. In this mode each surface is drawn as a series of planar regions, usually rectangles. Hidden line removal is typically used with such a representation. Static hidden line removal does not update which lines are hidden during rotation, but only once the screen is refreshed. Dynamic hidden line removal continuously updates which curves are hidden during rotations.
Facet wireframe Facet shaded •
Shaded mode. Shading can then be added to the facets, possibly with blending between the regions for a smoother display. Shading can also be static or dynamic. A lower quality of shading is typically used for dynamic shading, while high quality shading, with multiple light sources, textures, etc., requires a delay for rendering.
shaded
reflection lines
reflected image
CAD/CAM representation of a surface CAD/CAM systems use primarily two types of surfaces: •
Regular (or canonical) surfaces include surfaces of revolution such as cylinders, cones, spheres, and tori, and ruled surfaces (linear in one direction) such as surfaces of extrusion.
•
Freeform surfaces (usually NURBS) allow more complex shapes to be represented via freeform surface modeling.
Other surface forms such as facet and voxel are also used in a few specific applications.
CAE/FEA representation of a surface In computer-aided engineering and finite element analysis, an object may be represented by a surface mesh of node points connected by triangles or quadrilaterals (polygon mesh). More accurate, but also far more CPU-intensive, results can be obtained by using a solid mesh. The process of creating a mesh is called tessellation. Once tessellated, the mesh can be subjected to simulated stresses, strains, temperature differences, etc., to see how those changes propagate from node point to node point throughout the mesh.
VR/computer animation representation of a surface In virtual reality and computer animation, an object may also be represented by a surface mesh of node points connected by triangles or quadrilaterals. If the goal is only to represent the visible portion of an object (and not show changes to the object) a solid mesh serves no purpose, for this application. The triangles or quadrilaterals can each be shaded differently depending on their orientation toward the light sources and/or viewer. This will give a rather faceted appearance, so an additional step is frequently added
where the shading of adjacent regions is blended to provide smooth shading. There are several methods for performing this blending.
Wire frame model A wire frame model is a visual presentation of an electronic representation of a three dimensional or physical object used in 3D computer graphics. It is created by specifying each edge of the physical object where two mathematically continuous smooth surfaces meet, or by connecting an object's constituent vertices using straight lines or curves. The object is projected onto the computer screen by drawing lines at the location of each edge.
Sample rendering of a wireframe cube, icosahedron, and approximate sphere Using a wire frame model allows visualization of the underlying design structure of a 3D model. Traditional 2-dimensional views and drawings can be created by appropriate rotation of the object and selection of hidden line removal via cutting planes. Since wireframe renderings are relatively simple and fast to calculate, they are often used in cases where a high screen frame rate is needed (for instance, when working with a particularly complex 3D model, or in real-time systems that model exterior phenomena). When greater graphical detail is desired surface textures can be added automatically after completion of the initial rendering of the wireframe. This allows the designer to quickly review changes or rotate the object to new desired views without long delays associated with more realistic rendering. The wire frame format is also well suited and widely used in programming tool paths for DNC (Direct Numerical Control) machine tools.
2D computer graphics 2D computer graphics is the computer-based generation of digital images—mostly from two-dimensional models (such as 2D geometric models, text, and digital images) and by techniques specific to them. The word may stand for the branch of computer science that comprises such techniques, or for the models themselves.
Raster graphic sprites (left) and masks (right) 2D computer graphics are mainly used in applications that were originally developed upon traditional printing and drawing technologies, such as typography, cartography, technical drawing, advertising, etc.. In those applications, the two-dimensional image is not just a representation of a real-world object, but an independent artifact with added semantic value; two-dimensional models are therefore preferred, because they give more direct control of the image than 3D computer graphics (whose approach is more akin to photography than to typography). In many domains, such as desktop publishing, engineering, and business, a description of a document based on 2D computer graphics techniques can be much smaller than the correspoding digital image—often by a factor of 1/1000 or more. This representation is also more flexible since it can be rendered at different resolutions to suit different output devices. For these reasons, documents and illustrations are often stored or transmitted as 2D graphic files. 2D computer graphics started in the 1950s, based on vector graphics devices. These were largely supplanted by raster-based devices in the following decades. The PostScript language and the X Window System protocol were landmark developments in the field.
2D graphics techniques
2D graphics models may combine geometric models (also called vector graphics), digital images (also called raster graphics), text to be typeset (defined by content, font style and size, color, position, and orientation), mathematical functions and equations, and more. These components can be modified and manipulated by two-dimensional geometric transformations such as translation, rotation, scaling. In object oriented graphics, the image is described indirectly by an object endowed with a self-rendering method—a procedure which assigns colors to the image pixels by an arbitrary algorithm. Complex models can be built by combining simpler objects, in the paradigms of object-oriented programming.
Direct painting A convenient way to create a complex image is to start with a blank "canvas" raster map (an array of pixels, also known as a bitmap) filled with some uniform background color and then "draw", "paint" or "paste" simple patches of color onto it, in an appropriate order. In particular, the canvas may be the frame buffer for a computer display. Some programs will set the pixel colors directly, but most will rely on some 2D graphics library and/or the machine's graphics card, which usually implement the following operations: • • • •
paste a given image at a specified offset onto the canvas; write a string of characters with a specified font, at a given position and angle; paint a simple geometric shape, such as a triangle defined by three corners, or a circle with given center and radius; draw a line segment, arc of circle, or simple curve with a virtual pen of given width.
Extended color models Text, shapes and lines are rendered with a client-specified color. Many libraries and cards provide color gradients, which are handy for the generation of smoothly-varying backgrounds, shadow effects, etc.. (See also Gouraud shading). The pixel colors can also be taken from a texture, e.g. a digital image (thus emulating rub-on screentones and the fabled "checker paint" which used to be available only in cartoons). Painting a pixel with a given color usually replaces its previous color. However, many systems support painting with transparent and translucent colors, which only modify the
previous pixel values. The two colors may also be combined in fancier ways, e.g. by computing their bitwise exclusive or. This technique is known as inverting color or color inversion, and is often used in graphical user interfaces for highlighting, rubber-band drawing, and other volatile painting—since re-painting the same shapes with the same color will restore the original pixel values.
Layers The models used in 2D computer graphics usually do not provide for three-dimensional shapes, or three-dimensional optical phenomena such as lighting, shadows, reflection, refraction, etc.. However, they usually can model multiple layers (conceptually of ink, paper, or film; opaque, translucent, or transparent—stacked in a specific order. The ordering is usually defined by a single number (the layer's depth, or distance from the viewer). Layered models are sometimes called 2 1/2-D computer graphics. They make it possible to mimic traditional drafting and printing techniques based on film and paper, such as cutting and pasting; and allow the user to edit any layer without affecting the others. For these reasons, they are used in most graphics editors. Layered models also allow better anti-aliasing of complex drawings and provide a sound model for certain techniques such as mitered joints and the even-odd rule. Layered models are also used to allow the user to suppress unwanted information when viewing or printing a document, e.g. roads and/or railways from a map, certain process layers from an integrated circuit diagram, or hand annotations from a business letter. In a layer-based model, the target image is produced by "painting" or "pasting" each layer, in order of decreasing depth, on the virtual canvas. Conceptually, each layer is first rendered on its own, yielding a digital image with the desired resolution which is then painted over the canvas, pixel by pixel. Fully transparent parts of a layer need not be rendered, of course. The rendering and painting may be done in parallel, i.e. each layer pixel may be painted on the canvas as soon as it is produced by the rendering procedure. Layers that consist of complex geometric objects (such as text or polylines) may be broken down into simpler elements (characters or line segments, respectively), which are then painted as separate layers, in some order. However, this solution may create undesirable aliasing artifacts wherever two elements overlap the same pixel.
See also Portable Document Format#Layers.
2D graphics hardware Modern computer graphics card displays almost overwhelmingly use raster techniques, dividing the screen into a rectangular grid of pixels, due to the relatively low cost of raster-based video hardware as compared with vector graphic hardware. Most graphic hardware has internal support for blitting operations and sprite drawing. A co-processor dedicated to blitting is known as a Blitter chip. Classic 2D graphics chips of the late 1970s and early 80s, used in the 8-bit video game consoles and home computers, include: • •
Atari's ANTIC (actually a 2D GPU), TIA, CTIA, and GTIA Commodore/MOS Technology's VIC and VIC-II
2D graphics software Many graphical user interfaces (GUIs), including Mac OS, Microsoft Windows, or the X Window System, are primarily based on 2D graphical concepts. Such software provides a visual environment for interacting with the computer, and commonly includes some form of window manager to aid the user in conceptually distinguishing between different applications. The user interface within individual software applications is typically 2D in nature as well, due in part to the fact that most common input devices, such as the mouse, are constrained to two dimensions of movement. 2D graphics are very important in the control peripherals such as printers, plotters, sheet cutting machines, etc.. They were also used in most early video and computer games; and are still used for card and board games such as solitaire, chess, mahjongg, etc.. 2D graphics editors or drawing programs are application-level software for the creation of images, diagrams and illustrations by direct manipulation (through the mouse, graphics tablet, or similar device) of 2D computer graphics primitives. These editors generally provide geometric primitives as well as digital images; and some even support procedural models. The illustration is usually represented internally as a layered model, often with a hierarchical structure to make editing more convenient. These editors generally output graphics files where the layers and primitives are separately preserved in their original
form. MacDraw, introduced in 1984 with the Macintosh line of computers, was an early example of this class; recent examples are the commercial products Adobe Illustrator and CorelDRAW, and the free editors such as xfig or Inkscape. There are also many 2D graphics editors specialized for certain types of drawings such as electrical, electronic and VLSI diagrams, topographic maps, computer fonts, etc. Image editors are specialized for the manipulation of digital images, mainly by means of free-hand drawing/painting and signal processing operations. They typically use a directpainting paradigm, where the user controls virtual pens, brushes, and other free-hand artistic instruments to apply paint to a virtual canvas. Some image editors support a multiple-layer model; however, in order to support signal-processing operations like blurring each layer is normally represented as a digital image. Therefore, any geometric primitives that are provided by the editor are immediately converted to pixels and painted onto the canvas. The name raster graphics editor is sometimes used to contrast this approach to that of general editors which also handle vector graphics. One of the first popular image editors was Apple's MacPaint, companion to MacDraw. Modern examples are the free GIMP editor, and the commercial products Photoshop and Paint Shop Pro. This class too includes many specialized editors — for medicine, remote sensing, digital photography, etc.
Texture Texture refers to the properties held and sensations caused by the external surface of objects received through the sense of touch. Texture is sometimes used to describe the feel of non-tactile sensations. Texture can also be termed as a pattern that has been scaled down (especially in case of two dimensional non-tactile textures) where the individual elements that go on to make the pattern not distinguishable. Texture may also refer to: • • • •
Texture (music), a way to vaguely describe the overall sound of a piece of music Texture mapping, the application of a bitmap image to the surface computer 3D models Texture (crystalline), the property of a material's individual crystallites sharing some degree of orientation Texture (geology), refers to the physical appearance or character of a rock, such as grain size, shape, and arrangement, at both the megascopic or microscopic surface feature level.
• • •
Soil texture, describes the relative proportion of grain sizes of a soil or any unconsolidated material In cuisine, texture is the feel of food on the tongue and against the teeth. Adjectives include crunchy, soft, sticky, mushy, hard, spongy, airy. In painting, texture is the feel of the canvas based on the paint used and its method of application.
Shading Shading refers to depicting depth in 3D models by varying levels of darkness. Drawing
Example of shading. Shading is a process used in drawing for depicting levels of darkness on paper by applying more pressure with a drawing implement for darker areas, and less pressure for lighter areas. There are various techniques of shading including cross hatching where perpendicular lines of varying closeness are drawn in a grid pattern to shade an area. The closer the lines are together, the darker the area appears. Likewise, the farther apart the lines are, the lighter the area appears. The term has been recently generalized to mean that shaders are applied. Light patterns, such as objects having light areas and shaded areas, help when creating the illusion of depth on paper and on computer screens.
Computer Graphics In Computer Graphics, Shading refers to the process of altering a color based on its angle to lights and its distance from lights to create a photorealistic effect. Shading is performed during the rendering process.
Angle to Light Source Shading alters the colors of faces in your 3D model based on the angle of the surface to the sun or other lught sources. The first image below has the faces of the box rendered, but all in the same color. Edge lines have been rendered here as well which makes the image easier to see.
The second image is the same model rendered without edge lines. It is difficult to tell where one face of the box ends and the next begins. The third image has shading enabled, which makes the image more realistic and makes it easier to see which face is which.
Rendered image of box. This image has no shading of faces, but uses edge lines to separate the faces.
This is the same image with the edge lines removed.
This is same model rendered with shading of the faces to alter the colors of the 3 faces based on their angle to the light sources.
Distance Falloff Theoretically, two surfaces which are parallel, are illuminated the same amount from a distant light source, such as the sun. Even though one surface is further away, your eye sees more of it in the same space, so the illumination appears the same. Notice in the first image that the color on the front faces of the two boxes is exactly the same. It appears that the is a slight difference where the two faces meet, but this is an optical illusion because of the vertical edge below where the two faces meet. Notice in the second image that the surfaces on the boxes are bright on the front box and darker on the back box. Also the floor goes from light to dark as it gets farther away. This Distance Falloff effect produces images which appear more realistic without having to add additional lights to achieve the same effect.
Two boxes rendered with an OpenGL renderer. Note that the colors of the two front faces are the same even though one box is further away.
The same model rendered using ARRIS CAD which implements "Distance Falloff" to make surfaces which are closer to the eye appear brighter.
Light Sources
Shading effects from floodlight. An OpenGL interface allows shadows from the sun. However with Ray Trace Renderers you can add light bulbs, flood lights and spot lights. The intensity of the light is altered because of the angle of the surface to the light, the distance from the surface to the light, and because of the beam angle of the flood light.
Flat shading interpolation example
Flat vs Smooth Shading Flat shading is lighting technique used in 3D computer graphics. It shades each polygon of an object based on the angle between the polygon's surface normal and the direction of the light source, their respective colors and the intensity of the light source. It is usually used for high speed rendering where more advanced shading techniques are too computationally expensive. The disadvantage of flat shading is that it gives low-polygon models a faceted look. Sometimes this look can be advantageous though, such as in modeling boxy objects. Artists sometimes use flat shading to look at the polygons of a solid model they are creating. More advanced and realistic lighting and shading techniques include Gouraud shading and Phong shading
Rasterisation Rasterization or rasterisation is the task of taking an image described in a vector graphics format (shapes) and converting it into a raster image (pixels or dots) for output on a video display or printer.
Introduction The term rasterization can in general be applied to any process by which vector information can be converted into a raster format. In normal usage, the term refers to the popular rendering algorithm for displaying threedimensional shapes on a computer. Rasterization is currently the most popular technique for producing real-time 3D computer graphics. Real-time applications need to respond immediately to user input, and generally need to produce frame rates of at least 20 frames per second. Compared to other rendering techniques such as radiosity and raytracing approaches, rasterization is extremely fast. However, it is not based on physical light transport and is therefore incapable of correctly simulating many complex real-life lighting situations.
Basic Approach The most basic rasterization algorithm takes a 3D scene, described as polygons, and renders it onto a 2D surface, usually a computer monitor. Polygons are themselves represented as collections of triangles. Triangles are represented by 3 vertices in 3-space. At a very basic level, rasterizers simply take a stream of vertices, transform them into corresponding 2-dimensional points on the viewer’s monitor and fill in the transformed 2dimensional triangles as appropriate.
Transformations Transformations are usually performed by matrix multiplication. Quaternion math may also be used but that is outside the scope of this article. A 3 dimensional vertex may be transformed by augmenting an extra variable known as a homogeneous variable and left multiplying the resulting 4-space vertex by a 4 x 4 transformation matrix. The main transformations are Translation, Scaling, Rotation, and Projection.
A translation is simply the movement of a point from its original location to another location in 3-space by a constant offset. Translations can be represented by the following matrix:
X, Y, and Z are the offsets in the 3 dimensions, respectively. A scaling transformation is performed by multiplying the position of a vertex by a scalar value. This has the effect of scaling a vertex with respect to the origin. Scaling can be represented by the following matrix:
X, Y, and Z are the values by which each of the 3-dimensions are multiplied. Asymmetric scaling can be accomplished by varying the values of X, Y, and Z. Rotation matrices depend on the axis around which a point is to be rotated. Rotation about the X-axis:
Rotation about the Y-axis:
Rotation about the Z-axis:
θ in all each of these cases represent the angle of rotation. A series of translation, scaling, and rotation matrices can logically describe most transformations. Rasterization systems generally use a transformation stack to move the stream of input vertices into place. The transformation stack is a standard stack which stores matrices. Incoming vertices are multiplied by the matrix stack. As an illustrative example of how the transformation stack is used, imagine a simple scene with a single model of a person. The person is standing upright, facing an arbitrary direction while his head is turned in another direction. The person is also located at a certain offset from the origin. A stream of vertices, the model, would be loaded to represent the person. First, a translation matrix would be pushed onto the stack to move the model to the correct location. A scaling matrix would be pushed onto the stack to size the model correctly. A rotation about the y-axis would be pushed onto the stack to orient the model properly. Then, the stream of vertices representing the body would be sent through the rasterizer. Since the head is facing a different direction, the rotation matrix would be popped off the top of the stack and a different rotation matrix about the y-axis with a different angle would be pushed. Finally the stream of vertices representing the head would be sent to the rasterizer. After all points have been transformed to their desired locations in 3-space with respect to the viewer, they must be transformed to the 2-D image plane. The simplest projection, the Orthographic projection, simply involves removing the z component from transformed 3d vertices. Orthographic projections have the property that all parallel lines in 3-space will remain parallel in the 2-D representation. However, real world images are perspective images, with points far away appearing closer than points close to the viewer. A perspective projection transformation needs to be applied to these points. Conceptually, the idea is to transform the perspective viewing volume into the orthogonal viewing volume. The perspective viewing volume is a frustum, that is, a truncated
pyramid. The orthographic viewing volume is a rectangular box, where both the near and far viewing planes are parallel to the image plane. A perspective projection transformation can be represented by the following matrix:
F and N here are the distances of the far and near viewing planes, respectively. The resulting four vector will be a vector where the homogeneous variable is not 1. Homogenizing the vector, or multiplying it by the inverse of the homogeneous variable such that the homogeneous variable becomes unitary, gives us our resulting 2-D location in the x and y coordinates.
Clipping Once triangle vertices are transformed to their proper 2d locations, some of these locations may be outside the viewing window, or the area on the screen to which pixels will actually be written. Clipping is the process of truncating triangles to fit them inside the viewing area. The most common technique is the Sutherland-Hodgeman clipping algorithm. In this approach, each of the 4 edges of the image plane is tested at a time. For each edge, test all points to be rendered. If the point is outside the edge, the point is removed. For each triangle edge that is intersected by the image plane’s edge, that is, one vertex of the edge is inside the image and another is outside, a point is inserted at the intersection and the outside point is removed.
Scan Conversion The final step in the traditional rasterization process is to fill in the 2D triangles that are now in the image plane. This is also known as scan conversion. The first problem to consider is whether or not to draw a pixel at all. For a pixel to be rendered, it must be within a triangle, and it must be not be occluded, or blocked by
another pixel. There are a number of algorithms to fill in pixels inside a triangle, the most popular of which is the Sweep-Line Algorithm. Since it is difficult to know that the rasterization engine will draw all pixels from front to back, there must be some way of ensuring that pixels close to the viewer are not overwritten by pixels far away. A z buffer is the most common solution. The z buffer is 2d array corresponding to the image plane which stores a depth value for each pixel. Whenever a pixel is drawn, it updates the z buffer with its depth value. Any new pixel must check its depth value against the z buffer value before it is drawn. Closer pixels are drawn and farther pixels are disregarded. To find out a pixel's color, textures and shading calculations must be applied. A texture map is a bitmap that is applied to a triangle to define its look. Each triangle vertex is also associated with a texture and a texture coordinate (u,v) for normal 2-d textures in addition to its position coordinate. Every time a pixel on a triangle is rendered, the corresponding texel (or texture element) in the texture must be found. This is done by interpolating between the triangle’s vertices’ associated texture coordinates by the pixels on-screen distance from the vertices. In perspective projections, interpolation is performed on the texture coordinates divided by the depth of the vertex to avoid a problem known as perspective foreshortening. Before the final color of the pixel can be decided, a lighting calculation must be performed to shade the pixels based on any lights which may be present in the scene. There are generally 3 types of lights commonly used in scenes. Directional lights are lights which come from a single direction and have the same intensity throughout the entire scene. In real life, sunlight comes close to being a directional light, as the sun is so far away that rays from the sun appear parallel to Earth observers and the falloff is negligible. Point lights are lights with a definite position in space and radiate light evenly in all directions. Point lights are usually subject to some form of attenuation, or fall off in the intensity of light incident on objects farther away. Real life light sources experience quadratic falloff. Finally, spotlights are like real-life spotlights, with a definite point in space, a direction, and an angle defining the cone of the spotlight. There is also often an ambient light value that is added to all final lighting calculations to arbitrarily compensate for global illumination effects which rasterization can not calculate correctly.
There are a number of shading algorithms for rasterizers. All shading algorithms need to account for distance from light and the normal vector of the shaded object with respect to the incident direction of light. The fastest algorithms simply shade all pixels on any given triangle with a single lighting value. There is no way to create the illusion of smooth surfaces this way. Algorithms can also separately shade vertices, and interpolate the lighting value of the vertices when drawing pixels. The slowest and most realistic approach is to calculate lighting separately for each pixel. Common shading models include Gouraud shading and Phong shading.
Acceleration techniques To extract the maximum performance out of any rasterization engine, a minimum number of polygons should be sent to the renderer. A number of acceleration techniques have been developed over time to cull out objects which can not be seen.
Backface Culling The simplest way to cull polygons is to cull all polygons which face away from the viewer. This is known as backface culling. Since most 3d objects are fully enclosed, polygons facing away from a viewer are always blocked by polygons facing towards the viewer unless the viewer is inside the object. A polygon’s facing is defined by its winding, or the order in which its vertices are sent to the renderer. A renderer can define either clockwise or counterclockwise winding as front or back facing. Once a polygon has been transformed to screen space, its winding can be checked and if it is in the opposite direction, it is not drawn at all. Of course, backface culling can not be used with degenerate and unclosed volumes.
Spatial Data Structures More advanced techniques use data structures to cull out objects which are either outside the viewing volume or are occluded by other objects. The most common data structures are Binary Space Partitions, Octrees, and Cell and Portal Culling.
Further refinements
While the basic rasterization process has been known for decades, modern applications continue to make optimizations and additions to increase the range of possibilities for the rasterization rendering engine.
Texture filtering Textures are created at specific resolutions, but since the surface they are applied to may be at any distance from the viewer, they can show up at arbitrary sizes on the final image. As a result, one pixel on screen usually does not correspond directly to one texel. Some form of filtering technique needs to to be applied to create clean images at any distance. A variety of methods are available, with different tradeoffs between image quality and computational complexity.
Environment mapping Environment mapping is a form of texture mapping in which the texture coordinates are view-dependent. One common application, for example, is to simulate reflection on a shiny object. One can environment map the interior of a room to a metal cup in a room. As the viewer moves about the cup, the texture coordinates of the cup’s vertices move accordingly, providing the illusion of reflective metal.
Bump mapping Bump mapping is another form of texture mapping which does not provide pixels with color, but rather with depth. Especially with modern pixel shaders (see below), bump mapping create the feel of view and lighting-dependent roughness on a surface to enhance realism greatly.
Level of detail In many modern applications, the number of polygons in any scene can be phenomenal. However, a viewer in a scene will only be able to discern details of close-by objects. Level of detail algorithms vary the complexity of geometry as a function of distance to the viewer. Objects right in front of the viewer can be rendered at full complexity while objects further away can be simplified dynamically, or even replaced completely with 2d sprites.
Shadows
Lighting calculations in the traditional rasterization process do not account for object occlusion. Shadow maps and shadow volumes are two common modern techniques for creating shadows.
Hardware acceleration Starting in the 90’s, hardware acceleration for normal consumer desktop computers has become the norm. Whereas graphics programmers had earlier relied on hand-coded assembly to make their programs run fast, most modern programs are written to interface with one of the existing graphics API’s, which then drive a dedicated GPU. The latest GPUs feature support for programmable pixel shaders which drastically improve the capabilities of programmers. The trend is towards full programmability of the graphics pipeline.
Raster graphics
Suppose the smiley face in the top left corner is an RGB bitmap image. When zoomed in, it might look like the big smiley face to the right. Every square represents a pixel. Zoomed in further we see three pixels whose colors are constructed by adding the values for red, green and blue. A raster graphics image, digital image, or bitmap, is a data file or structure representing a generally rectangular grid of pixels, or points of colour, on a computer monitor, paper, or other display device. The color of each pixel is individually defined; images in the RGB color space, for instance, often consist of colored pixels defined by three bytes—one byte each for red, green and blue. Less colorful images require less information per pixel; an image with only black and white pixels requires only a single bit for each pixel. Raster graphics are distinguished from vector graphics in that vector graphics represent an image through the use of geometric objects such as curves and polygons. A bitmap or a raster image corresponds bit for bit with an image displayed on a screen, probably in the same format as it would be stored in the display's video memory or maybe as a device independent bitmap. A bitmap is characterized by the width and height
of the image in pixels and the number of bits per pixel, which determines the number of colors it can represent. A colored raster image (or pixmap) will usually have pixels with between one and eight bits for each of the red, green, and blue components, though other color encodings are also used, such as four- or eight-bit indexed representations that use vector quantization on the (R, G, B) vectors. The green component sometimes has more bits than the other two to allow for the human eye's greater discrimination in this component. The quality of a raster image is determined by the total number of pixels (resolution), and the amount of information in each pixel (often called color depth). For example, an image that stores 24 bits of color information per pixel (the standard for all displays since around 1995) can represent smoother degrees of shading than one that only stores 16 bits per pixel, but not as smooth as one that stores 48 bits (technically; this would not be discernible by the human eye). Likewise, an image sampled at 640 x 480 pixels (therefore containing 307,200 pixels) will look rough and blocky compared to one sampled at 1280 x 1024 (1,310,720 pixels). Because it takes a large amount of data to store a high-quality image, data compression techniques are often used to reduce this size for images stored on disk. Some techniques sacrifice information, and therefore image quality, in order to achieve a smaller file size. Compression techniques that lose information are referred to as "lossy" compression. Raster graphics cannot be scaled to a higher resolution without loss of apparent quality. This is in contrast to vector graphics, which easily scale to the quality of the device on which they are rendered. Raster graphics are more practical than vector graphics for photographs and photo-realistic images, while vector graphics are often more practical for typesetting or graphic design. Modern computer monitors typically display about 72 to 130 pixels per inch (PPI), and some modern consumer printers can resolve 2400 dots per inch (DPI) or more; determining the most appropriate image resolution for a given printer resolution can be difficult, since printed output may have a greater level of detail than can be discerned on a monitor. In the printing and prepress industries raster graphics are known as contones (from "continuous tones") whereas vector graphics are known as line work.
Raster example
To illustrate the matter further, here is the letter "J": J A close look at the letter will appear as such, where the "X" and "." characters represent a grid of pixels: .....X .....X .....X .....X .....X .....X X....X X....X .XXXX.
A computer sees something more like this, where "." represents a zero and "X" represents a one: 000001 000001 000001 000001 000001 000001 100001 100001 011110
Here is the resulting image: . Here it is again magnified 20 times:
Where a zero appears, the computer software instructs its video hardware to paint the current background color. A one calls for the current foreground color. The software
makes a distinction between the colors of adjacent pixels, which together form an image. This is the basic principle behind graphics editing on a computer. In 3D computer graphics, the concept of a flat raster of pixels is sometimes extended to a three dimensional volume of voxels. In this case, there is a regular grid in three dimensional space with a sample containing color information at each point in the grid. Although voxels are powerful abstractions for dealing with complex 3D shapes, they can have impractically large memory requirements for storing a sizable array. Consequently, vector graphics are used more frequently than voxels for producing 3D imagery. Raster graphics was first patented by Texas Instruments in the 1970s[citation needed], and is now ubiquitous.
Vector graphics
Example showing effect of vector graphics on ppm scale: (a) original vector-based illustration; (b) illustration magnified 8x as a vector image; (c) illustration magnified 8x as a raster image. Raster images scale poorly, but vector-based images can be scaled indefinitely without degradation. (Images were converted to JPEG for display on this page.) Vector graphics (also called geometric modeling or object-oriented graphics) is the use of geometrical primitives such as points, lines, curves, and polygons, which are all
based upon mathematical equations to represent images in computer graphics. It is used by contrast to the term raster graphics, which is the representation of images as a collection of pixels (dots).
Overview All modern current computer video displays translate vector representations of an image to a raster format. The raster image, containing a value for every pixel on the screen, is stored in memory. Starting in the earliest days of computing in the 1950s and into the 1980s, a different type of display, the vector graphics system, was used. In these systems the electron beam of the CRT display monitor was steered directly to trace out the shapes required, line segment by line segment, with the rest of the screen remaining black. This process was repeated many times a second to achieve a flicker-free or near flicker-free picture. These systems allowed very high-resolution line art and moving images to be displayed without the (for that time) unthinkably huge amounts of memory that an equivalent-resolution raster system would have needed. These vector-based monitors were also known as X-Y displays.
Vectorising is good for removing unnecessary detail from a photograph. This is especially useful for information graphics or line art. (Images were converted to JPEG for display on this page.)
An original photograph, a JPEG raster image.
Vectorising is good for reducing file sizes for lower bandwidth delivery, while retaining enough detail for aesthetic appeal and photorealism.(Images were converted to JPEG for display on this page.) One of the first uses of vector graphic displays was the US SAGE air defense system. Vector graphics systems were only retired from U.S. en route air traffic control in 1999, and are likely still in use in military and specialized systems. Vector graphics were also used on the TX-2 at the MIT Lincoln Laboratory by computer graphics pioneer Ivan Sutherland to run his program Sketchpad in 1963. Subsequent vector graphics systems include Digital's GT40 . There was a home gaming system that used vector graphics called Vectrex as well as various arcade games like Asteroids and Space Wars. The Tektronix 4014 also deserves a mention even though the display was static. The term vector graphics is mainly used today in the context of two-dimensional computer graphics. It is one of several modes an artist can use to create an image on a raster display. Other modes include text, multimedia and 3D rendering. Virtually all modern 3D rendering is done using extensions of 2D vector graphics techniques. Plotters used in technical drawing still draw vectors directly to paper.
Motivation
For example, consider a circle of radius r. The main pieces of information a program needs in order to draw this circle are 1. 2. 3. 4.
the radius r the location of the center point of the circle stroke line style and colour (possibly transparent) fill style and colour (possibly transparent)
Advantages to this style of drawing over raster graphics: •
•
•
•
•
This minimal amount of information translates to a much smaller file size compared to large raster images (the size of representation doesn't depend on the dimensions of the object). Correspondingly, one can indefinitely zoom in on e.g. a circle arc, and it remains smooth. On the other hand, a polygon representing a curve will reveal being not really curved. On zooming in, lines and curves need not get wider proportionally. Often the width is either not increased or less than proportional. On the other hand, irregular curves represented by simple geometric shapes may be made proportionally wider when zooming in, to keep them looking smooth and not like these geometric shapes. The parameters of objects are stored and can be later modified. This means that moving, scaling, rotating, filling etc. doesn't degrade the quality of a drawing. Moreover, it is usual to specify the dimensions in device-independent units, which results in the best possible rasterization on raster devices. From a 3-D perspective, rendering shadows is also much more realistic with vector graphics, as shadows can be abstracted into the rays of light which form them. This allows for photo realistic images and renderings.
Typical primitive objects • • • • • •
lines and polylines polygons circles and ellipses Bézier curves Bezigons Text (in computer fonts such as TrueType where each letter is created from Bézier curves)
This list is not complete. There are various types of curves (Catmull-Rom splines, NURBS etc.), which are useful in certain applications. Often, a bitmap image is considered as a primitive object. From the conceptual view, it behaves as a rectangle.
Vector operations Vector graphics editors typically allow to rotate, move, mirror, stretch, skew, generally perform affine transformations of objects, change z-order and combine the primitives into more complex objects. More sophisticated transformations include set operations on closed shapes (union, difference, intersection, etc.) Vector graphics are ideal for simple or composite drawings that need to be deviceindependent, or do not need to achieve photo-realism. For example, the PostScript and PDF page description languages use a vector graphics model.
Printing One key aspect or vector art is key for printing. Since the art is made from a series of mathematical points it will print very crisp no matter how you resize the art. For instance you can take the same vector logo and print it on a business card or blow it up to billboard size and keep the same crisp quality. In contrast a raster graphic would blur incredibly if it were blown up from a business card size to billboard size.
3D modeling In 3D computer graphics, vectorized surface representations are most common (bitmaps can be used for special purposes such as surface texturing, height-field data and bump mapping). At the low-end, simple meshes of polygons are used to represent geometric detail in applications where interactive frame rates or simplicity are important. At the high-end, where one is willing to trade-off higher rendering times for increased image quality and precision, smooth surface representations such as Bézier patches, NURBS or Subdivision surfaces are used. One can however achieve a smooth surface rendering from a polygonal mesh through the use of shading algorithms such as Phong.
Raster to vector
A photograph in JPEG format
The above photograph vectorised with AutoTrace in the Delineate GUI Raster to vector software and hardware technology for converting raster graphics to vector graphics are used in a number of fields, most notable in conjunction with CAD and GIS systems. For example drawings that only exist in physical form (blueprints, plots of lost files, etc.) can be converted into CAD files using a procedure called "Paper-to-CAD conversion" or drawing conversion, involving scanning and vectorization, or digitization. Additionally, photographic images can be vectorised in order to incorporate them into an otherwise geometric design. In the process, the photograph may be transformed into a silhouette, for example.
Raster image processor
A raster image processor (RIP) is a component used in a printing system which produces a bitmap. The bitmap is then sent to a printing device for output. The input may be a page description in a high-level page description language such as PostScript, Portable Document Format, XPS or another bitmap of higher or lower resolution than the output device. In the latter case, the RIP applies either smoothing or interpolation algorithms to the input bitmap to generate the output bitmap. Raster image processing is the process and the means of turning vector digital information such as a PostScript file into a high-resolution raster image. Originally RIPs were a rack of electronic hardware which received the page description via some interface (eg RS232) and generated a "hardware bitmap output" which was used to enable or disable each pixel on a real-time output device such as an optical film scanner. A RIP can be implemented either as a software component of an operating system or as a firmware program executed on a microprocessor inside a printer, though for high-end typesetting, standalone hardware RIPs are sometimes used. Ghostscript and GhostPCL are examples of software RIPs. Every PostScript printer contains a RIP in its firmware. A RIP chip is used in laser printers to communicate raster images to a laser.
Page layout
Consumer magazine sponsored advertisements and covers rely heavily on professional page layout skills to compete for visual attention. Page layout is the part of graphic design that deals in the arrangement and style treatment of elements (content) on a page. Beginning from early illuminated pages in hand-copied books of the Middle Ages and proceeding down to intricate modern magazine and catalog layouts, proper page design has long been a consideration in printed material. With print media, elements usually consist of type (text), images (pictures), and occasionally place-holder graphics for elements that are not printed with ink such as die/laser cutting, foil stamping or blind embossing. Since the advent of personal computing, page layout skills have expanded to electronic media as well as print media. The electronic page is better known as a (GUI) graphical user interface. Page layout for interactive media overlaps with (and is often called) interface design. This usually includes GUI elements and multimedia in addition to text and still images. Interactivity takes page layout skills from planning attraction and eye flow to the next level of planning user experience in collaboration with software engineers and creative directors. A page layout can be designed in a rough paper and pencil sketch before producing, or produced during the design process to the final form. Both design and production can be achieved using hand tools or page layout software. Producing the most popular electronic
page (the web page) may require knowledge of markup languages along with WYSIWYG editors to compensate for incompatibility between platforms. Special considerations must be made for how the layout of an HTML page will change (reflow) when resized by the end-user. cascading style sheets are often required to keep the page layout consistent between web browsers.
Grids versus templates Grids and templates are page layout design patterns used in advertising campaigns and multiple page publications, including web sites. •
A grid is a set of invisible to the end-user/audience guidelines (visible in the design process) for aligning and repeating elements on a page. A page layout may or may not stay within those guidelines, depending on how much repetition or variety the design style in the series calls for. Grids are meant to be flexible. Using a grid to layout elements on the page may require just as much or more graphic design skill than was required to design the grid.
•
In contrast, a template is more rigid. A template involves repeated elements mostly visible to the end-user/audience. Using a template to layout elements usually involves less graphic design skill than was required to design the template. Templates are used for minimal modification of background elements and frequent modification (or swapping) of foreground content.
Most desktop publishing software allows for grids in the form of a page filled with automatic dots placed at a specified equal horizontal and vertical distance apart. Automatic margins and booklet spine (gutter) lines maybe specified for global use throughout the document. Multiple additional horizontal and vertical lines may be placed at any point on the page. Invisible to the end-user/audience shapes may be placed on the page as guidelines for page layout and print processing as well. Software templates are achieved by duplicating a template data file, or with master page features in a multiple page document. Master pages may include both grid elements and template elements such as header and footer elements, automatic page numbering, and automatic table of contents features.
Front-end versus back-end With modern media technology, there is much overlap between visual communications (front-end) and information technology (back-end). Large print publications (thick
books, especially instructional in nature) and electronic pages (web pages) require meta data for automatic indexing, automatic reformatting, database publishing, dynamic page display and end-user interactivity. Much of the meta data (meta tags) must be hand coded or specified during the page layout process. This divides the task of page layout between artists and engineers, or tasks the artist/engineer to do both. More complex projects may require two separate designs: page layout design as the frontend, and function coding as the back-end. In this case, the front-end may be designed using the alternate page layout technology such as image editing software or on paper with hand rendering methods. Most image editing software includes features for converting a page layout for use in a WYSIWYG editor or features to export graphics for desktop publishing software. WYSIWYG editors and desktop publishing software allow front-end design prior to back end-coding in most cases. Interface design and database publishing may involve more technical knowledge or collaboration with information technology engineering in the front-end.
Adobe InDesign History Adobe InDesign is a desktop publishing (DTP) application produced by Adobe Systems. Launched as a direct competitor to QuarkXPress, it initially had difficulty in converting users. In 2002 it was first to release a Mac OS X-native version. Also, InDesign CS and CS2 were bundled with Photoshop, Illustrator, and Acrobat in the Creative Suite. InDesign can export documents in Adobe's Portable Document Format and offers multilingual support that Quark users can get only by purchasing a much more expensive "Passport" version. InDesign was the first major DTP application to support Unicode for text processing, advanced typography of OpenType fonts, advanced transparency features, layout styles, and optical margin alignment. The cross-platform scriptability using Javascript still sets it apart. Finally, it features tight integration and user interface similarities with other Adobe offerings such as Illustrator and Photoshop. InDesign was positioned as a higher-end alternative and successor to Adobe's own PageMaker. InDesign's primary adopters are periodical publications, posters, and other print media. Longer documents are usually still designed with FrameMaker (manuals and technical documents) or QuarkXPress (books, catalogs). The combination of a relational
database, InDesign and Adobe InCopy word processor, which uses the same formatting engine as InDesign, is the heart of dozens of publishing systems designed for newspapers, magazines, and other publishing environments. New versions of the software introduced new file formats. Adobe had upset its user base because significant changes in InDesign CS prevented users from downsaving to older versions of InDesign. However, with the new release of InDesign CS2, opening a higherversion document in InDesign CS is allowed through the InDesign Interchange (.inx) format, an XML-based representation of the document. Versions of InDesign CS updated with the 3.01 April 2005 update (available free from Adobe's Web site) can read files saved from InDesign CS2 exported to this format. Adobe is currently developing InDesign CS3 (and the rest of Creative Suite 3) as a Universal Binary for native Intel and PowerPC Mac compatibility and is expecting to ship InDesign CS3 in Q2 2007. Because CS2 has code tightly integrated with the PPC architecture and hence not natively compatible with the Intel processors used in Macs starting from 2006, porting these products is a huge endeavor. Adobe decided to devote all its resources to developing CS3 (including integrating Macromedia products acquired in 2005) rather than recompiling CS2 and developing CS3 simultaneously. This decision has upset many Intel Mac early-adoptors, especially since Adobe CEO Bruce Chizen initially announced "Adobe will be first with a complete line of Universal applications."
Server Version In October 2005 Adobe released a server version of InDesign, called "InDesign CS2 Server". This enables solutions that allow page editing and page layout functionality in a web browser.
Versions • • • • • • •
InDesign 1.0 shipped August 16, 1999. InDesign 1.5 shipped in early 2001. InDesign 2.0 shipped in January 2002 (just days before QuarkXPress 5). InDesign CS (3.0) shipped in October 2003. InDesign CS2 (4.0) shipped in May 2005. InDesign Server released. InDesign CS3 (5.0) expected release in Q2 2007 (Including Universal Binary versions for Intel-based Macs)
Adobe Photoshop Adobe Photoshop, or simply Photoshop, is a graphics editor developed and published by Adobe Systems. It is the current market leader for commercial bitmap and image manipulation, and, in addition to Adobe Acrobat, is one of the best-known pieces of software produced by Adobe Systems. It is considered the industry standard in most jobs related to the use of visual elements. Photoshop is available for Mac OS, Mac OS X and Microsoft Windows; versions up to Photoshop 9.0 can also be used with other operating systems such as Linux using software such as CrossOver Office. Past versions of the program were ported to the SGI IRIX and Sun Solaris platforms, but official support for this port was dropped after version 3.
Features
Simple composite image produced with various tools in Photoshop. Although primarily designed to edit images for paper-based printing, Photoshop is used increasingly to produce images for the World Wide Web. Recent versions bundle a related application, Adobe ImageReady, to provide a more specialized set of tools for this purpose. Photoshop also has strong ties with other Adobe software for media editing, animation and authoring. Files in Photoshop's native format, .PSD, can be exported to and from Adobe ImageReady, Adobe Illustrator, Adobe Premiere, After Effects and Adobe Encore DVD to make professional standard DVDs, provide non-linear editing and special effects services such as backgrounds, textures and so on for television, film and the Web. For example, Photoshop CS broadly supports making menus and buttons for DVDs. For .PSD files exported as a menu or button, it only needs to have layers, nested in layer sets with a cueing format and Adobe Encore DVD reads them as buttons or menus.
Photoshop can deal with a number of different color models: • • • • • •
RGB color model Lab color model CMYK color model Grayscale Bitmap Duotone
The most recent major version, released in 2005, is version 9. This iteration of the program is marketed as "Photoshop CS2." "CS" reflects its integration with "Adobe's Creative Suite" and a number "2" because it is the second version released since Adobe rebranded their products under the CS umbrella. Photoshop CS2 features important new additions such as multiple layer selecting and "warp," a curve-friendly version of the transform tool. For the digital photography enthusiasts, the "reduce grain" filter can help to improve pictures taken in low light. In an effort to break away from previous versions of the application and to reinforce its belonging with the new line of products, Photoshop even dropped one classic graphic feature from its packaging: the Photoshop eye, which was present in different manifestations from versions 3 to 7. Photoshop CS versions now use feathers as a form of identification.
Camera RAW 3.x The latest version comes with Adobe Camera RAW, a plugin developed by Thomas Knoll which can read several RAW file formats from various digital cameras and import them directly into Photoshop. A preliminary version of the RAW plugin was also available for Photoshop 7.0.1 as a $99 USD optional purchase. While Photoshop is the industry standard image editing program for professional raster graphics, its relatively high suggested retail price (US $600, approximately) has led to a number of competing graphics tools being made available at lower prices. To compete in this market, and to counter unusually high rates of piracy of their professional products,
Adobe has introduced a Photoshop Elements, a version of Photoshop with many professional features removed, for under $100 US; this is aimed firmly at the general consumer market since the feature cuts make it less desirable for prepress work.
File formats Photoshop has the ability to read and write many common raster and vector image formats such as .png, .gif, .jpeg, etc. It also has several native file formats: •
• •
The PSD (Photoshop Document) format stores an image as a set of layers, including text, masks, opacity, blend modes, color channels, alpha channels, clipping paths, and duotone settings. Photoshop's popularity means that the PSD format is widely used, and it is supported to some extent by most competing software. The PSB format is a newer version of PSD designed for files over 2 GB. The PDD format is a version of PSD that only supports the features found in the discontinued PhotoDeluxe software.
Industry impact
An example of deletion manipulation. The original is on the left. The development of digital image manipulation redefined the photographic postproduction industry. It revolutionized the art of photo retouching and processing by streamlining workflows: intricate procedures which took hours or days, and could only be performed by skilled photographers, now became relatively easy even for amateur artists. Digital image manipulation has contributed greatly to the world of photography by enabling manipulations that were previously difficult or impossible, and by allowing nondestructive and easily reversible changes to images. As the market leader throughout this history, Photoshop was responsible for many of the innovations that are now commonplace.
During the digital photography revolution of the 1990s, Photoshop became even more entrenched as the industry standard. Many photographers used the software to migrate to all-digital workflows, greatly increasing the quality of the finished image. Photoshop was one of the first image processors that could prepare images for the World Wide Webwhich effectively opened up the Internet as a new medium for graphic artists and photographers. It could be argued that Photoshop is primarily responsible for transforming the Web from its 1994 text-based roots into the graphical, interactive, userfriendly New Media Web of today. With the rise of graphics tablets, most notably from Wacom, programs such as Adobe Photoshop and Corel Painter have been used more and more to create original pieces of art. Using the pressure sensitive tablet can greatly improve the effects of the paint brush, eraser, or other tools. Tablets are used worldwide by professional comic book illustrators, architects, studio artists, etc. Even ILM, the special effects company that worked for the Star Wars films, used tablets combined with Photoshop in post-production.
Culture The term photoshopping is a neologism, meaning "editing an image", regardless of the program used (compare with Google used as a verb). Adobe discourages use of the term out of fear that it will undermine the company's trademark; an alternate term which leaves out the Photoshop reference is "photochop". The term photoshop is also used as a noun referring to the altered image. This is especially popular amongst members of the websites Something Awful, Worth1000, B3ta and Fark where photoshopping is an institution. The goal of altering an image, subtly or blatantly, is to make it humorous or clever, often via the use of obscure in-jokes and pop culture references. Another widespread practice is putting the face of a celebrity onto a nude or pornographic image. Photoshop competitions in all these varieties have become a favorite pastime for many professional and amateur users of the software. The term is sometimes used with a derogatory intent by artists to refer to images that have been retouched instead of originally produced. A common issue amongst users of all skill levels is the ability to avoid in one's work what is referred to as "the Photoshop look" (although such an issue is intrinsic to many graphics programs). Even more recent is the so-called "sport" of Photoshop Tennis. A match in this hobby consists of two Photoshop artists passing back and forth (usually via email) a Photoshop
image file. Each player will make changes to the file and send it back. After a predetermined number of turns an independent judge will review the edits made and declare a winner. This allows artists to both showcase and hone their Photoshop skills. In the vein of Photoshop Tennis, artists also engage in collaboration. This hobby consists of two Photoshop artists passing back and forth (usually via email) a Photoshop image file (.psd). Each artist adds elements to the composition, working with the other to create an image. There is not usually an element of competition involved with such an activity.
Development The brothers Thomas Knoll and John Knoll began development on Photoshop in 1987. Version 1 was released by Adobe in 1990. The program was intended from the start as a tool for manipulating images that were digitized by a scanner, which was a rare and expensive device in those days.
Photoshop logos
Release history
Version
1.0
Platform
Mac OS
Codename
Release date February 1990
Significant changes
2.0
Mac OS
2.0.1
Mac OS
2.5
Mac OS Windows
Fast Eddy
Merlin Brimstone
IRIX, Solaris 2.5.1
Mac OS Mac OS
3.0
Tiger Mountain
Windows, IRIX, Solaris
4.0
Mac OS, Windows
4.0.1
Mac OS, Windows
June 1991 January 1992 November 1992 November 1993 1993 September 1994 November 1994
Big Electric November 1996 Cat
Mac OS, Windows
5.0.1
Mac OS, Windows
1999
5.5
Mac OS, Windows
February 1999
6.0
Mac OS, Windows
7.0
Paths
• •
Tabbed Palettes Layers
• •
Adjustment Layers Actions (macros)
•
• • •
Editable type (previously, type was rasterized as soon as it was added) Multiple Undo (History Palette) Color Management Magnetic Lasso
• •
Bundled with ImageReady Extract
• • •
Vector Shapes Updated User Interface "Liquify" filter
New painting engine Removed alpha channel support from TGA output process in favor of "embedded alphas"
• •
Camera RAW 1.x (optional plugin) Reinstated standard alpha channel support for TGA processing, and removed "embedded alphas"
• • • • • • • •
Camera RAW 2.x Highly modified "Slice Tool" Shadow/Highlight Command Match Colour command "Lens blur" filter Smart Guides Real-Time Histogram Detection and refusal to print scanned images of various banknotes Macrovision copy protection based on Safecast DRM technology
August 2002
Dark Matter
October 2003
•
CS2 Mac OS X, (9.0) Windows
Space April 2005 Monkey
• • • • • • • • •
• • •
Universal CS3 Mac, Windows
Alternatives
Spring 2007 Red Pill (expected)
•
Camera RAW 3.x "Smart Objects" Image Warp Spot healing brush Red-Eye tool Lens Correction filter Smart Sharpen Vanishing Point Better memory management on 64bit PowerPC G5 Macintosh machines running Mac OS X 10.4 High dynamic range imaging (HDRI) support Scripting support for JavaScript and other languages More smudging options, such as "Scattering" Full support for the Intel-based Mac platform
There are many other bitmap-graphics editors available, but none have come close to Photoshop's popularity among professionals. The most popular competitors in other markets are the commercial packages Macromedia Fireworks, Corel Photo-Paint (bundled with CorelDRAW), Corel Paint Shop Pro Photo XI and Ulead PhotoImpact. Less well-known alternatives include the open source GIMP, the open source Paint.NET (although it bills itself as a replacement for Microsoft Paint), and the commercial Pixel image editor. In cinema, CinePaint (a fork of GIMP) has gained significant market share.
Adobe Illustrator Adobe Illustrator is a vector-based drawing program developed and marketed by Adobe Systems.
History Adobe Illustrator was first developed for the Apple Macintosh in 1986 (shipping in Jan 1987) as a logical commercialization of Adobe's in-house font development software and PostScript file format.
Initial release In many ways Illustrator's release was a gamble: the Macintosh did not have high market share, the only printer that could output Illustrator documents was Apple's own LaserWriter (also very new and expensive), and the drawing paradigm of Bézier curves was novel to the mainstream user. Not only did the Macintosh show only monochrome graphics, but display options were basically limited to its built-in 9" monitor. Illustrator helped drive the development of larger monitors for the Macintosh. Illustrator was a reliable, capable product, however, and its relatively steep learning curve let users quickly appreciate that the new paradigm was not only better, but finally solved the problem of imprecision from existing programs like MacDraw. It also provided a tool for people who could neither afford nor learn high-end (and perhaps overkill) software such as AutoCAD. Illustrator successfully filled a niche between painting and CAD programs.
Illustrator's power and simplicity derive from the choice of Bézier curves as the primary document element. A degenerate curve provides a line, and circles and arcs (trigonometric shapes) can be emulated closely enough. In a novel twist, Adobe also made Illustrator documents true PostScript files -- if one wanted to print them, one could send them directly to a PostScript printer instead of printing them from Illustrator. Since PostScript is a readable text format, third-party developers also found it easy to write programs that generated Illustrator documents.
Versions 1.1–3 Illustrator 1.0 was quickly replaced by 1.1, which enjoyed widespread use. An interesting feature of Illustrator 1.1's packaging was the inclusion of a videotape in which Adobe founder John Warnock demonstrated the program's features. The next version (in a novel versioning scheme) was 88 (to match the year of release which was 1988). That was followed by 3.0, which emphasized improved text layout capabilities, including text on a curve. At around this time, Aldus had their FreeHand program available for the Macintosh, and despite having a higher learning curve and a less-polished interface, it could do true blend (gradient) fills, which kept FreeHand as a "must have" in DTP shops along with the rest of the "Big Four": Illustrator, PageMaker, and QuarkXPress. It would be many years before Illustrator supported true blended fills (in Illustrator 5), and this was perhaps the one feature that users uniformly complained was lacking. Adobe was willing to take risks with Illustrator's user interface. Instead of following Apple's UI guidelines to the letter or imitating other popular Macintosh programs, they made it possible to switch between the various navigation tools (i.e, Zoom and Pan) using various keyboard key combinations. Probably from Adobe's past experience in-house, it knew what it was doing, and the majority of users vindicated the design as "slick." Unfortunately, Apple later chose one of the key combinations (Command-Space) as the keyboard layout changer, and Windows treated another (the Alt key) as a system key...
Versions 2–5 Although Adobe developed Illustrator primarily for the Macintosh during its first decade, it sporadically supported other platforms. In the early 1990s, Adobe released versions of Illustrator for NeXT, Silicon Graphics IRIX, and Sun Solaris platforms, but they were discontinued due to poor market acceptance. The first version of Illustrator for Microsoft Windows, version 2.0, was released in early 1989, but it was a flop. The next Windows
version, version 4.0, was widely criticized as being too similar to Illustrator 1.1 instead of the Macintosh 3.0 version, and certainly not the equal of Windows' most popular illustration package CorelDraw. (Note that there were no versions 2.0 or 4.0 for the Macintosh.) Version 4 was, however the first version of Illustrator to support editing in preview mode, which did not appear in a Macintosh version until 5.0 in 1993.
Versions 6–7 With the introduction of Illustrator 6 in 1996, Adobe made critical changes in the user interface with regards to path editing (and also to converge on the same user interface as Adobe Photoshop), and many users opted not to upgrade. To this day, many users find the changes questionable. Illustrator also began to support TrueType, making the "font wars" between PostScript Type 1 and TrueType largely moot. Like Photoshop, Illustrator also began supporting plug-ins, greatly and quickly extending its abilities. With true ports of the Macintosh versions to Windows starting with version 7 in 1997, designers could finally standardize on Illustrator. Corel did port CorelDraw 6.0 to the Macintosh in late 1996, but it was received as too little, too late. Aldus ported FreeHand to Windows but it was not the equal of Illustrator. Adobe bought Aldus in 1994 for PageMaker, and as part of the transaction it sold FreeHand to Macromedia. With the rise of the Internet, Illustrator was enhanced to support Web publishing, rasterization previewing, PDF, and SVG.
Branding Starting with version 1.0, Adobe chose to license Sandro Botticelli's "The Birth of Venus" from the Bettmann Archive and use the portion containing Venus' face as Illustrator's branding image. Warnock desired a Renaissance image to evoke his vision of Postscript as a new Renaissance in publishing, and Adobe employee Luanne Seymour Cohen, who was responsible for the early marketing material, found Venus' flowing tresses a perfect vehicle for demonstrating Illustrator's strength in tracing smooth curves over bitmap source images. Over the years, the rendition of this image on Illustrator's splash screen has become more stylized as Illustrator gains new features.
Versions CS–CS 2
Adobe Illustrator is currently (as of April 2005) in version 12 (called CS2 to reflect its integration with Adobe's Creative Suite) and is available for both the Mac OS X and Microsoft Windows operating systems. The image of Venus was replaced in Illustrator CS (version 11) with a stylized flower to conform to the Creative Suite's nature imagery. Among the new features included in Illustrator CS2 are Live Trace, Live Paint, a control palette, and custom workspaces. Live Trace allows for the conversion of bitmap imagery into vector art. Live Paint allows users more flexibility in applying color to objects, specifically those that overlap.
Version CS 3 This version of Adobe Illustrator is scheduled to be released in Q2 2007. The Mac version will be a Universal Binary. All previous Mac versions on the program were forced to run with "Rosetta," an emulator for running PPC code on new Intel Macintosh computers. This emulation causes Adobe software to run slower in most cases. Adobe announced it would not release a Universal Binary of CS2 because rewriting the code to be universal-compliant requires a major development effort. Many would-be Illustrator buyers that own new Intel-based Macs are therefore delaying all purchases of Adobe CS products or seeking alternative solutions. It is unknown what new features it will have.
Release history
Version Platforms
Release date
Code name
1.0
Mac OS
January 1987
1.1
Mac OS
March 19, 1987
Inca
2.0
Windows
January 1989
Pinnacle
88
Mac OS
March 1988
Picasso
3
Mac OS, NeXT, other Unixes October 1990
3.5
Silicon Graphics
1991
4
Windows
May 1992
3.5
Solaris
1993
5
Mac OS
June 1993
Saturn
5.5
Mac OS, Solaris
June 1994
Janus
4.1
Windows
1995
6
Mac OS
February 1996
Popeye
7
Mac/Windows
May 1997
Simba
8
Mac/Windows
September 1998 Elvis
9
Mac/Windows
June 2000
10
Mac/Windows
November 2001 Paloma
Desert Moose
Kangaroose
Matisse
CS (11) Mac/Windows
October 2003
Pangaea/Sprinkles
CS2 (12) Mac/Windows
April 27, 2005
Zodiac
CS3 (13) Mac/Windows
expected Q2 2007 Jason
Macromedia Dreamweaver Macromedia Dreamweaver is a web development tool, created by Macromedia (now Adobe Systems), which is currently in version 8. Initial versions of the application served as simple WYSIWYG HTML editors but more recent versions have incorporated notable support for many other web technologies such as CSS, JavaScript, and various serverside scripting frameworks. Dreamweaver has enjoyed widespread success since the late 1990s and currently holds more than 70% of the HTML editor market. The software is available for both the Mac and Windows platforms, but can also be run on Unix-like platforms through the use of emulation software such as Wine. As a WYSIWYG editor, Dreamweaver can hide the details of pages' HTML code from the user, making it possible for non-experts to easily create web pages and sites. Some web developers criticize this approach as producing HTML pages that are much larger than they should be, which can cause web browsers to perform poorly. This can be particularly true because the application makes it very easy to create table-based layouts. In addition, some web site developers have criticized Dreamweaver in the past for producing code that often does not comply with W3C standards though this has improved considerably in recent versions. The most recent version of Dreamweaver (8) performs poorly on the Acid2 Test, developed by the Web Standards Project. However, Macromedia has increased the support for CSS and other ways to lay out a page without tables in later versions of the application. Dreamweaver allows users to use most browsers to preview websites, provided that they are installed on their computer. It also has some site management tools, such as the ability to find and replace lines of text or code by whatever parameters specified across the entire site, and a templatization feature for creating multiple pages with similar structures. The behaviors panel also allows creation of basic JavaScript without any coding knowledge. With the advent of version MX, Macromedia incorporated dynamic content creation tools into Dreamweaver. In the spirit of HTML WYSIWYG tools, it allows users to connect to databases (such as MySQL and Microsoft Access) to filter and display content using scripting technologies such as Active Server Pages(ASP), ASP.NET, ColdFusion, JavaServer Pages(JSP), PHP, and more without any previous programming experience.
Alternative solutions for web database application development are Alpha Five and Filemaker. A highly regarded aspect of Dreamweaver is its extensible architecture. "Extensions", as they are known, are small programs, which any web developer can write (usually in HTML and Javascript) and anyone can download and install, which provide added functionality to the software. Dreamweaver is supported by a large community of extension developers who make extensions available (both commercial and free) for most web development tasks from simple rollover effects to full-featured shopping carts.
"Click to activate and use this control" Issue As of April 11, 2006 (assuming all relevant patches from Microsoft have been applied), any file embedded using the default object/embed code and viewed in Microsoft Internet Explorer will prompt users to "click to activate and use this control", before it will run. This is due to a patent dispute between the University of California, Eolas and Microsoft that has concluded by finding against Microsoft and awarding damages of $521 million against the company . In an interview with eWeek, Eolas founder Michael Doyle said, "We have from the beginning had a general policy of providing non-commercial users royalty-free licenses ... the open-source community shouldn't have anything to fear from us" , so most other browsers should not be forced to follow suit. The dispute was over the whole concept of embedded, interactive ActiveX controls in IE, using the object and similar HTML elements, which Michael Doyle patented for UC in 1993, then licensed exclusively to a company he founded (Eolas) in 1994 . There are potential workarounds for IE users, but implementing them will mean code alterations to countless web pages that currently make use of Flash and other embedded ActiveX applications. There is a workaround for this issue, essentially using JavaScript to place the .swf file into a web document, rather than the standard
