A movie animator creates the artwork that goes into an animated feature film. This work can be performed in two-dimensional (2D) animation or three-dimensional (3D) animation, and the type of style chosen will have a major impact on the type of work done by an animator. While certain principals of animation remain the same, movie animators for 2D projects will do very different work from an animator working in 3D and often require very different skill sets.
2D animation was, traditionally, created using ink and paint to create images on clear pieces of thin plastic. These individual images, called cels, were then assembled to create images through persistence of vision. Modern 2D animation is usually made in a computer, but otherwise the process is similar. A movie animator working in the current animation industry will usually work with computers to create the artwork regardless of whether he or she is working on 2D animation or 3D animation.
The 2D animation being created today is typically made in a computer, but is still made one cel at a time. These individual images are then played together, one after another, to create moving images. A movie animator working on 2D projects will usually create an entire scene, and often produce hundreds or thousands of frames of animation to be played together. While some animators may focus on background animation and others on character animation, there will usually be a single animator creating the movement of a character throughout a single scene. For major projects the animator might only make key frames and have someone else create the in-between frames, but the animator will still create most of the motion.
With 3D animation, however, there will often be multiple animators working together to create a single scene. Scenes in 3D animated works are somewhat more complex, so a single movie animator will likely focus on a single aspect of a scene. For example, one animator might work on the large motions of a character or characters, while another animator then adds smaller details like facial expressions and mouth movements for dialog. Another movie animator might work on background details, like an object swaying in the wind or moving when the characters interact with it.
All of this work together creates the final 3D animated scene. Since computer animation allows incredibly detailed 3D objects to be created, the animators often have many minor features that have to be considered and included to keep the scene looking realistic. Though this has changed how animators work together, it has remained a group effort that comes from many animators putting in hundreds of hours of work.