Definition of Computer-generated Imagery (CGI)
Computer-generated imagery (CGI) (Pronounced “See Gee Eye”) is the application of computer graphics to create or contribute to images in art, printed media, video game, films, television programes, commercials and simulators. The visual scenes may be dynamic or static, and may be 2D, though the term “CGI” is most commonly used to refer to3D computer graphics used for creating scenes or special effects in films and television. They can also be used by a home user and edited together on programs such as Window Movie Maker or i-Movie.
The term computer animation refers to dynamic CGI rendered as a movie. The term virtual world refers to agent-based, interactive environments.
Computergraphics software is used to make computer-generated imagery for movies, etc. Recent availability of CGI software and increased computer speeds have 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.
An example of a computer-generated, natural-looking, static fractal landscape.
Half of this image is a photo, and half is a CGI rendering.
Graphic Concepts
Medical Visualizations
Story Artwork
Technical Renderings
A short computer-generated imagery (CGI) history
The history of computer-generated imagery goes hand in hand with the history of the computer, as the computer evolved CGI effects got possible.
For the origins of computer-generated imagery we need to go back to the year 1968. In this year a group of Russian mathematicians and physicists headed by N.Konstantinov created a mathematic model of a moving cat across a screen. A program was made for a specialized computer called BESM-4. The computer printed hundreds of frames to be later converted into usable film material.
In the 1970′s CGI realy got a hold in the designing community. With many people experimenting with new movie and designing techniques the technology rapidly evolved. Just a few years after moving a cat across the screen the 2D animator Peter Foldes created the first CGI animated short film drawn on a data tablet. Foldes also used the world’s first key frame animation software, invented by Nestor Burtnyk and Marceli Wein.
New CGI developments followed shortly as a few months later in 1971 the first CGI was used in television programs. Two years later in 1973 the first 2D animated effect was realized by Yul Brynner in the point of view shot in Westworld.
The first 3D computer-generated imagery was created in the film Futureworld in 1976. In a scene the hand and face of the actor was enhanced with the use CGI. Futureworld used 2D digital compositing to materialize characters over the background.
After these first steps into discovering the possibilites of CGI a probably familiar man named George Lucas saw it’s possibilities. George Lucas conceived the popular Star Wars franchise which made use of top edge CGI effects at the time and many that were never seen before. The 1977 movie became a huge box office hit and became an inspiration for many CGI effects that followed.
Many movies using CGI effects follwed soon after Star Wars: A New Hope which showed the real potention and mind boggling possibilities of computer-generated imagery. Superman: The Movie (1978) conceived the first computer-generated title sequence. The movies Alien (1979) and Black Hole (1979) pushed the boundaries of CGI further by conceiving 3D wireframe rasters that created more detailed CGI effects.
As the computer developed and became more integrated into society CGI did to. In the 1980′s a bombardment of CGI milestones were made which most importantly were: the first CGI human character (with the first use of 3D shaded CGI), the invention of the Genesis effect for creating alien-like landscapes like used in Star Trek 2: The Wrath of Khan (1982), TRON (1982) which made use of 15 minutes of fully rendered CGI footage including the famous light cycle sequence. Many box office hits used CGI effects like the first water 3D CGI effect in the film hit “The Abyss” and the first digital composite in Indiana Jones: The Last Crusade (1989).
As we entered the age of the internet and the spreading of the personal computer CGI effects began to become more and more photo realistic. Major steps forward were made in the creation of movies as Terminator 2: Judgement Day which figured 3D CGI motion pictures. Two years later in 1993 Steven Spielberg raised the bar by creating the first eye dropping photo realistic computer-generated creatures in Jurassic Parc. More computer generated movies followed as CGI got a hold in many state of the art movies. In 1995 Toy Story got the title of first fully CGI animated movie. Last but not least the 1990′s CGI era ended with the blockbuster movie The Matrix (1999) which was the first to use the so called bullet time effect.
As the movie industry matured the game industry started to get a foot hold to. In the so called fifth generation gaming consoles fully 3D playable games got more and more popular. With the release of the Playstation (1994) and the Nintendo 64 (1996) games got their first fully 3D supported gaming platforms. games as Super Mario 64, Doom, Final Fantasy and Crash Bandicoot set the standard for many computer-generated games that followed.
As we entered the 21st century CGI possibilities became almost endless and more and more mixed with the authentic film footage. Movies as The Lord of the Rings: The Fellowship of the Ring (2001), The Matrix: Reloaded (2003) and The Polar Express (2004) pushed the boundaries and possibilities of CGI further. Lord of the Rings was the first to make use of artificial intelligence for it’s digitally created characters as it also created the first photo realistic motion captured character. The Matrix: Reloaded thereby was the first to use Universal Capture to capture more frames in an image. Furthermore in 2004 the animated film “The Polar Express” (2004) pushed the boundary by being to first to use motion capture on all it’s movie characters.
Many breakthroughs followed as we entered the realm of photo realistic CGI effects. The last years computer generated imagery has almost become the standard in any feature film that hits the cinema’s. In 2009 the best selling movie of all time, Avatar, pushed CGI to yet a higher level, creating a movie that was fully made with performance capture, transforming the actors into photo realistic 3D characters.
Aside the movie industry the gaming industry made many improvements to. Implementing motion capture techniques and other CGI techniques that were also used in movies. Maturing into a fully dynamic industry in the last twenty years, games as Grand Theft Auto and Crysis keep advancing the CGI standard over the last several years on gaming platforms. An interesting detail is that games and movies are starting to show more and more similarities. As games become more story driven games are becoming more like playable movies. Bioware and Lucas Arts upcoming story driven game Star Wars: The Old Republic (scheduled for a 2011 release) is a good example of this merge between movies, animations and games.
Static images and landscapes
Not only do animated images form part of computer-generated imagery, natural looking landscapes, such as fractal landscapes are also generated via computer algorithms. A simple way to generate fractal surfaces is to use an extension of the triangular mesh method, relying on the construction of some special case of ade Rham curve, e.g. midpoint displacement. For instance, the algorithm may start with a large triangle, then recursively zoom in by dividing it into 4 smaller Sierpinski triangles, then interpolate the height of each point from its nearest neighbors. The creation of a Brownian surface may be achieved not only by adding noise as new nodes are created, but by adding additional noise at multiple levels of the mesh. Thus a topographical map with varying levels of height can be created using relatively straightforward fractal algorithms. Some typical, and easy to program fractals used in CGI are the plasma fractal and the more dramatic fault fractal.
A large number of specific techniques have been researched and developed to produce highly focused computer-generated effects, e.g. the use of specific models to represent the chemical weathering of stones to model erosion and produce an “aged appearance” for a given stone-based surface.
Architectural scenes
Modern architects use services from computer graphic firms to create 3-dimensional models for both customers and builders. These computer generated models can be more accurate than traditional drawings. Architectural animation (which provides animated movies of buildings, rather than interactive images) can also be used to see the possible relationship a building will have in relation to the environment and its surrounding buildings. The rendering of architectural spaces without the use of paper and pencil tools is now a widely accepted practice with a number of computer-assisted architectural design systems.
Architectural modelling tools allow an architect to visualize a space and perform “walk-throughs” in an interactive manner, thus providing “interactive environments” both at the urban and building levels. Specific applications in architecture not only include the specification of building structures such as walls and windows, and walk-throughs, but the effects of light and how sunlight will affect a specific design at different times of the day.
Architectural modelling tools have now become increasingly internet-based. However, the quality of internet-based systems still lags those of sophisticated inhouse modelling systems.
In some applications, computer-generated images are used to “reverse engineer” historical buildings. For instance, a computer-generated reconstruction of the monastery at Georgenthal in Germany was derived from the ruins of the monastery, yet provides the viewer with a “look and feel” of what the building would have looked like in its day.
Visual Studies 