Automatic in-betweening in computer assisted animation by exploiting 2.5D modelling techniques

This paper introduces a new method for automatic in-betweening in computer assisted traditional animation. The solution is based on novel 2.5D modelling and animation techniques within the context of a multi-level approach, starting with basic 2D drawing primitives (curves) at level 0, over explicit 2.5D modelling structures at level 1 and inclusion of 3D information by means of skeletons at level 2, to high-level deformation tools (and possibly other tools for supporting specific purposes such as facial expression) at level 3. The underlying methodologies are explained and implementation results are elucidated.