Abstract: The theory of elasticity describes deformable materials such as rubber, cloth, paper, and flexible metals. We employ elasticity theory to construct differential equations that model the behavior of non-rigidcurves, surfaces, and solids as a functionof time. Elastically deformable models are active: they respond in a natural way to applied forces, constraints, ambient media, and impenetrable obstacles. The models are fundamentally dynamic and realistic animationis created by numerically solving their underlying differential equations. Thus, the description of shape and the description of motion are unified.
Demetri Terzopoulos, John C. Platt, Alan H. Barr,