An On-line Occlusio-Culling Algorithm for FastWalkthrough in Urban Areas

Abstract

We describe a fast algorithm to speed up rendering of scenes for walkthroughs in urban environments. Our occlusion culling algorithm takes advantage of temporal coherence in image space. As such, occlusion calculation is performed online only when needed. This enables us to employ intelligent occluder-selection and culling algorithms. We do not preprocess visibility information or pre-select occluders. Therefore, we can update scenes dynamically at a little cost. The algorithm features a tradeoff between accuracy and efficiency. While it approximates visibility testing, our experiments show that errors occur rarely.