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 movies, 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 because it is far better and more physical than other ways , such as constructing miniatures for effects shots or hiring a cheap deal of 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 or other things to the project.

1 History
2 Creating characters and objects on a computer
3 Free CGI Tools Available Online for Download
4 See also
5 References
6 External links

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History

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 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 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, it revolutionized the movie industry. It marked Hollywood’s transition from stop-motion animation and conventional optical effects to digital techniques.

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.

Image:Movie poster toy story.jpg In 1995, the first fully computer-generated feature film, Pixar's Toy Story, was a resounding commercial success. Additional digital animation studios such as Blue Sky Studios (Fox) 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. [1]

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. Computer-generated extras also became used extensively in crowd scenes. 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.

Image:Final Fantasy 01.jpg

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, however, and after creating one more film using a similar visual style (Final Flight of the Osiris, a short subject which served as a prologue to The Matrix Reloaded), Square Pictures closed down.

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.

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Creating characters and objects on a computer

Image:Gollum.jpg

Computer animation combines Vector graphics with programmed movement. The starting point is often a stick figure in which the position of each feature (limb, mouth etc) is defined by an Avars (animation variable). CGI is another term for computer animation, but usually refers to 3D high resolution with the emphasis on movies.

The character "Woody" in Pixar's movie Toy Story, for example, uses 700 Avars. Successive sets of Avars control all movement of the character from frame to frame. Once the stick model is moving in the desired way, the avars are incorporated into a full Wire frame model or a model built of polygons. Finally surfaces are added, requiring a lengthy process of Rendering to produce the final scene.

There are several ways of generating the Avar values to obtain realistic motion. Motion capture uses lights or markers on a real person acting out the part, tracked by a video camera. Or the Avars may be set manually using a joystick or other form input control. Toy Story uses no motion tracking, probably because manual control by a skilled animator can produce effects not easily acted out by a real person.

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Free CGI Tools Available Online for Download

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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.

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