Physically-based simulation of objects represented by surface meshes

Objects and scenes in virtual worlds such as 3-d computer games are typically represented by polygonal surface meshes. On the other hand, physically-based simulations of deformations or fracture effects require volumetric representations such as tetrahedral meshes. In this paper we propose techniques to generate volumetric meshes dynamically for objects represented by surface meshes allowing the simulation of physical effects such as motion, deformation and fracture. We use the Finite Element Method based on cubical elements of uniform size. Regular cube meshes have several advantages over geometrically more complex representations. Because of their simplicity, cube meshes can be generated quickly by voxelizing objects while neither geometry nor stiffness information needs to be stored explicitly. The low memory consumption makes physically-based animation possible for large scenes even on game consoles. We animate the original high resolution surface mesh by coupling it to the underlying volumetric mesh. This way, the regular structure of the volumetric mesh is hidden from the user We also propose a technique to fracture the surface mesh along with the cube mesh which keeps the surface watertight and results in realistic fracture patterns.