Evaluation of collisions between polygonal models in virtual assembly

Collisions between polygonal models may not reflect collisions between real objects in reality because of polygonal approximation and designed tolerance. This problem reduces the reliability of simulation in virtual assembly and sometimes even results in wrong conclusions. To solve the problem, we propose a novel collision evaluation algorithm based on generalized penetration depth, approximation information and tolerance information. Given two interfered polygonal models, generalized penetration depth is calculated using relative motion information. Then two thresholds, which are based on approximation information and tolerance information, are integrated to evaluate collisions between polygonal models. In order to distinguish the status of collisions for furfure analysis, the collisions between polygonal models are categorized into three types by evaluation algorithm, namely real collision, potential collision and fake collision. Computational efficiency and accuracy of the evaluation algorithm are verified in virtual assembly.