Computer assistance for traditional animation can be
considered part of the new area of Non-photorealistic Rendering - we recommend a visit to the Web page by Craig
Reynolds [11]. Current research on computer assistance for
traditional animation focuses on two main lines: geometrybased methods and image-based methods. In the first, geometric objects are created in order to support the animation process. The latter uses image-based techniques to
render the 2D character without jumping to 3D geometry.
The great advantage of the geometry-based methods is the
possibility of supporting both the frame-to-frame coherence
and the shading process. However, these methods cannot
cope with more fluid animations, where few strokes would
change the implied geometry drastically. On the other hand,
image-based methods work directly with the vivid drawings
made by the artist.