Computer-generated imagery

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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 pre-rendered "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.

1 History
2 Digital Grading
3 References
4 External links

[edit] 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. and Magic">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.

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.

[edit] 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.

[edit] References

CG101: A Computer Graphics Industry Reference ISBN# 073570046X Unique and personal histories of early computer graphics production, plus a comprehensive foundation of the industry for all reading levels.
F/X Gods, by Anne Thompson, Wired, February 2005.