Consistent Collision and Self-Collision Handling for Deformable Objects

Interactive environments with dynamically deforming objects play an important role in physically-based simulation and animation, ranging from computational surgery to computer games. These environments require efficient and robust methods for basic simulation tasks, such as deformation, collision detection and collision response. This thesis investigates novel collision handling components especially suited for deformable objects. The focus lies on versatile techniques featuring efficient data structures, self-collision support and n-body collision information while still delivering interactive performance. All presented methods aim for visually-plausible and consistent behavior, which is in accordance to the requirements of typical target applications. The first approach detects collisions and self-collisions of deformable objects based on a variant of spatial partitioning. It employs a hashing scheme which allows for very efficient n-body collision queries between different object primitives, such as vertices, lines, triangles and tetrahedrons. The second collision detection method generates a volumetric approximation of the intersection volume to detect collisions and self-collisions. The computation of the volumetric representation is done in image-space to take advantage of potential graphics hardware acceleration. The technique allows for several volumetric collision queries: An explicit representation of the intersection volume, a vertex-in-volume check and a self-collision test. Finally, a technique is proposed that computes consistent n-body penetration depth information in order to reduce collision response artifacts. It considers a set of close surface features to avoid discontinuities and it applies a propagation scheme in case of large penetrations to minimize non-plausible, inconsistent collision information. A test suite composed of several carefully selected experiments is used to analyze the characteristics and the performance of each presented technique. The methods are also integrated into a hysteroscopy simulator and a complete framework for interactive simulation of dynamically deforming objects. Both applications demonstrate the capability and applicability of the collision handling components presented in this thesis.