Traditional animation (or classical animation, cel animation or hand-drawn animation) is an animation technique where each frame is drawn by hand. The technique was the dominant form of animation in cinema until the advent of computer animation.
This process is used for many productions, for example, the most common types of puppets are clay puppets, as used in The California Raisins , Wallace and Gromit and Shaun the Sheep by Aardman, and figures made of various rubbers, cloths and plastic resins, such as The Nightmare Before Christmas and James and the Giant Peach.
Computer-generated imagery (CGI) revolutionized animation. The first fully computer-animated feature film was Pixar's Toy Story (1995). The process of CGI animation is still very tedious and similar in that sense to traditional animation, and it still adheres to many of the same principles.
A principal difference of CGI animation compared to traditional animation is that drawing is replaced by 3D modeling, almost like a virtual version of stop-motion. A form of animation that combines the two and uses 2D computer drawing can be considered computer aided animation.