Visibility in Computer Graphics (colloquy-cycle)

I will introduce a classification of visibility problems in three dimensions that is based on the dimension of the space of lines involved in the problem. In particular the following three classes will be discussed: visibility along a line, visibility from a point, and visibility from a region. Further, I will present a conservative hierarchical visibility algorithm for a moving viewpoint that is suitable for real time visibility culling. The algorithm uses occlusion tree that is a modification of the shadow volume BSP tree. Finally, I will mention some general refinements that make use of spatial and temporal coherence in the scope of hierarchical visibility algorithms.