Inbetweening for computer animation utilizing moving point constraints

Abstract

This paper presents an approach to computerized inbetweening which allows the animator more control over an interpolation sequence than existing keyframe techniques. In our approach, the animator specifies in addition to a set of keyframe constraints, a set of new constraints called moving points . Moving points are curves in space and time which constrain both the trajectory and dynamics of certain points on the keyframes. The sets of keyframes and moving points form a constraint or patch network specification of the desired dynamics. Several algorithms are presented for inbetweening or completing such a patch network. By measuring these algorithms with respect to a set of evaluation criteria, the algorithm which best meets our interpolation needs is selected.