Physically plausible simulation for character animation

Artist-created animated characters can exhibit stylized, engaging behavior, but require considerable effort to construct, while interactive applications require numerous motions and variations to create a dynamic, believable character. This paper describes a method for generating some of these variations automatically: given a stream of poses, our method simulates plausible responses to physical disturbances and environmental variations. Our quasi-physical simulation accounts for the dynamics of the character and surrounding objects, but does not require the motion to be physically valid, making it suitable for both realistic and stylized, cartoony motions. It further does not require any preprocessing, allowing it to run as an online filter that transforms the output of any real-time animation system. Our prototype runs at 50 Hz, on bipeds and quadrupeds with over 50 degrees of freedom, and generates plausible variations for walking, running, hopping, crawling, rolling, cartwheeling, and other motions.