Fast computation of contact points for robotic simulations based on CAD models without tessellation

Computing multiple contact points between geometric models evolved in a virtual 3D environment is central to many robotic simulation applications. While this task can be performed efficiently and robustly between complex polyhedra, using the exact analytic geometric models issued by CAD modelers still suffers from efficiency limitations. Yet models composed of smooth surfaces are required to ensure smooth contact constraints, thus avoiding possible numerical artifacts which may dramatically affect the behavior of the system in the case of functional contacts. This paper builds on the observation that industrial CAD models are mostly composed of simple surfaces to perform an off-line identification of similar features and build a bounding volume hierarchy in order to locate potential contacts. Those are then computed by dedicated analytic methods, or an iterative root-finder, depending on the actual geometric representations of the features. In the context of dynamic simulation of robotic tasks, our method exhibits interactive computation times while naturally providing better result accuracy than existing polyhedron-specific algorithms.