Specifying the motion of an animated linked figure such that itachieves given tasks (e.g., throwing a ball into a basket) and performsthe tasks in a realistic fashion (e.g., gracefully, and followingphysical laws such as gravity) has been an elusive goalfor computer animators. The spacetime constraints paradigm hasbeen shown to be a valuable approach to this problem, but itsuffers from computational complexity growth as creatures andtasks approach those one would like to animate. The...