Computer-based, three-dimensional animators do not draw frames as they did in traditional two-dimensional animation, where the characters and objects appear relatively flat and 2D on the screen (e.g., Homer in The Simpsons, Fig. 11.21).

In this Halloween episode, Homer transforms from 2D to 3D--as can be seen in Figures 11.21 and 11.22.

The first Homer was created through conventional cel animation. The second was built with computer-generated imagery (CGI). See how much more rounded and bulbous he appears in Figure 11.22? That can be one effect of CGI work.

Click here to see Homer's transformation in action.