Spacetime constraints are a new method for creating character animation. The animator specifies what the character has to do, for instance, "jump from here to there, clearing a hurdle in between;" how the motion should be performed, for instance "don't waste energy," or "come down hard enough to splatter whatever you land on;" the character's physical structure---the geometry, mass, connectivity, etc. of the parts; and the physical resources available to the character to accomplish the motion, for instance the character 's muscles, a floor to push off from, etc. The requirements contained in this description, together with Newton 's laws, comprise a problem of constrained optimization. The solution to this problem is a physically valid motion satisfying the "what" constraints and optimizing the "how" criteria. We present as examples a Luxo lamp performing a variety of coordinated motions. These realistic motions conform to such principles of traditional animation as anticipation, squas...

Computer animation has two methods of modeling: one is physical-based modeling; the other is example-based modeling. Although the example-based modeling now is the leading direction, physical-based modeling has its important as the basement in the area of computer animation. Spacetime constraints are a physical-based method for creating character animation. It specifies what the character should do-- “moving from here to there, ” how the motion should be performed, for instance “minimize waste energy”, the character’s physical structure—the geometry, mass, connectivity, etc. of the parts; and the physical resources available to the character to accomplish the motion, for instance the character’s muscles, a floor to push off from, etc. The requirements contained in this description, together with Newton’s laws, comprise a problem of constrained optimization. The solution to this problem is a physically valid motion satisfying the “what ” constraints and optimizing the “how ” criteria. I experiment as examples a simple accelerate particle and discuss the solution for a swing pendulum and a luxo lamp. These realistic motions conform to such principles of traditional animation as anticipation,