CSG Based Collision Detection

This paper describes a complete method to detect collision among CSG modeled objects within a computer animation system. Since objects that are modeled with the constructive solid geometry paradigm can have very complex shapes, especially when they consist of curved primitives, collision detection is performed in three stages. Bounding volumes in each node of the CSG tree are used to determine whether a collision is likely to occur between each pair of objects. If overlapping bounds are discovered, spatial subdivision is used to reduce the complexity of the CSG objects for further analysis. In those voxels, which cover parts of both objects, a redundancy test is performed for each primitive to determine whether the objects interpenetrate. Curved primitives are adaptively approximated by circumscribed and inscribed polyhedrons.