Computer-generated imagery (CGI) is artwork created using three-dimensional (3-D) computer graphics software. Unlike other forms of digital artwork, CGI works are made using models “sculpted” with computer software. The models can be viewed from multiple angles or set up to be posed like dolls. CGI is used extensively in motion pictures, television, and electronic games. With CGI, artists can create detailed backgrounds or fantastic creatures. Such elements might be too expensive or impractical to build in the real world.
How CGI is made.
Most CGI models are made up of polygons. Polygons are simple, two-dimensional shapes, such as triangles or squares. By connecting polygons of different sizes and shapes at angles, artists can make any form they desire. A major computer-generated character in a feature film might consist of hundreds of thousands of polygons.
After sculpting the form, the artist assigns such attributes as texture and color to the model’s surface. Polygons that make up a character’s face, for example, will have texture, color, and other properties resembling skin. Polygons on armor will look metallic. The last step is rendering. In rendering, the software calculates how the model’s form and textures look under certain lights and from certain angles. The final rendered image is a two-dimensional (2-D) “picture” of the model.
History.
CGI was first developed in the 1960’s and 1970’s. Several movies in the 1970’s used CGI, although in very limited ways. The first CGI film character was a stained-glass knight in The Young Sherlock Holmes (1985). The visual effects company Industrial Light & Magic (ILM) created the character. ILM also created CGI dinosaurs in the 1993 film Jurassic Park, directed by Steven Spielberg. The dinosaurs were the first CGI characters that looked realistic alongside live actors. Toy Story, a 1995 film by the Walt Disney Company and Pixar Animation Studios, was the first feature film consisting entirely of CGI.
By the early 2000’s, CGI animation had become a widely used special effects technique. Fully CGI-animated feature films ranked as a popular form of family entertainment.
See also Animation (Computer animation); Computer graphics (In entertainment and the arts); Motion picture (The computer revolution); Motion picture (Motion pictures today); Pixar Animation Studios.
