Interactive viewing of large geometric databases using multiprocessor graphics workstations

In many visualization applications as well as computer graphics we need to consider large amounts of objects in order to render one image. In many cases rendering can be preceded by a culling phase which employs simple mechanisms to reject most of the objects. As a result, only a very small portion of the model has to actually go through the time consuming process of hidden object removal. We report on such a culling mechanism that is based on regular space subdivision into cells. These cells are classified into opaque and transparent and a cell-to-cell visibility algorithm determines, for a given cell, which other cells are potentially visible. Only the objects in the potentially visible set of cells are actually submitted to the hidden object removal algorithm. We report on the 2D implementation of the algorithm and its performance for walkthrough the interior of capillary blood vessels. We propose several improvements to our methods and suggest a simple way to extend it to 3D.