with the help of computers, the technique to render realistic 3D computer graphics (CG), or 3D computer-generated imagery (CGI), is unique to computers.
The more general term computer-generated imagery (CGI) encompasses both static scenes and dynamic images, while computer animation only refers to the moving images. Modern computer animation usually uses 3D computer graphics, although 2D computer graphics are still used for stylistic, low bandwidth, and faster real-time renderings. Sometimes, the target of the animation is the computer itself, but sometimes film as well.
Computer animation is essentially a digital successor to the stop motion techniques used in traditional animation with 3D models and frame-by-frame animation of 2D illustrations. Computer-generated animations are more controllable than other more physically based processes, 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 graphic artist to produce such content without the use of actors, expensive set pieces, or props. To create the illusion of movement, an image is displayed on the computer monitor and repeatedly replaced by a new image that is similar to it, but advanced slightly in time (usually at a rate of 24 or 30 frames/second). This technique is identical to how the illusion of movement is achieved with television and motion pictures.
was originally set up to be a live-action/CG animation hybrid with background plate miniature sets and the main characters composited into the scene as motion-captured computer graphics. The results were not satisfactory. The studio then turned to its production partners at Pacific Data Images (PDI), who helped Shrek get to its final, computer-animated look.
Ice Age (2002)
was originally conceived in the 1990s during the Disney Renaissance. Blue Sky Studios got the opportunity with the Ice Age script to turn it into a computer animated comedy, Chris Wedge and Carlos Saldanha took over as the directors.