Computing Conservative Multifocal Visibility using the z-Buffer

Greg Marsden and Leonidas Guibas
Stanford University

Abstract:

Despite advancements in computer graphics technology, algorithmic model simplification plays a crucial role in manipulating and rendering complex polygonal models.

In this paper, we describe the theoretical justification for a new technique that combines nearby viewpoints into a volume, and uses these viewpoint volumes to simplify complex models by removing occluded polygons. Existing techniques calculate occlusion relationships between polygons based on geometric proximity measurements; this new technique determines hidden geometry based on the inability of occluded polygons to intercept visibility rays.

This technique can take advantage of hardware acceleration in the z-buffer to further accelerate removal of hidden surfaces.

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Sample output:

Self occlusion found by the multifocal z-buffer in a 12,000 polygon tree.

(a) Original textured model	(b) Model processed by multifocal z-buffer	(c) Geometry invisible to the viewing volume (23.3%)

©2001 Greg Marsden, All rights reserved.