Sometimes referred to as 3D CGI, 3D animation is a type of animation that uses computer generated images to create animated scenes. Compared to 2D animation, or traditional animation, 3D has much more depth, and it looks much more realistic.
An animated scene starts with one picture, which is referred to a frame. The next frame is a picture that is slightly advanced a few milliseconds in time. After hundreds or thousands of these frames are flashed on a screen in rapid succession, they give the illusion of a moving picture.
The majority of the animated feature movies and short animated skits today are created with 3D animation, and this is a rapidly growing industry.
Source: The Art Career Project