Model for Physically based Animation and

This paper presents the design of an expandable animation system in which rigid and deformable multi-body systems are animated from the high-level model of physical objects. This new model called dream (Deformable and Rigid objects EEcient for Animation Modelling) makes the simulation of rigid and de-formable interconnected objects easy to design and to implement. dream is based on a uniied abstracted model described by an entity relationship formalism. Traditionnal physically based models such as rigid solids and deformable objects (described by nite elements or by punctual mass-spring meshes) come from this common formalism. That is why our system integrates and uniies the physical models used in computer animation. Then the motion equations are automatically computed in a symbolic form by applying the principle of virtual works and Lagrange's equations. Theoretical, numerical and practical aspects of the model implementation and some experimental results are presented. Finally, the applicability of our animation system to scientiic simulation is discussed.