Instant Visibility

Peter Wonka, Michael Wimmer, François Sillion. Computer Graphics Forum (Proc. Eurographics 2001), 20(3). September 2001. [Paper]
(Günther Enderle Award for the best paper at Eurographics 2001)


We present an online occlusion culling system which computes visibility in parallel to the rendering pipeline. We show how to use point visibility algorithms to quickly calculate a tight potentially visible set (PVS) which is valid for several frames, by shrinking the occluders used in visibility calculations by an adequate amount. These visibility calculations can be performed on a visibility server, possibly a distinct computer communicating with the display host over a local network. The resulting system essentially combines the advantages of online visibility processing and region-based visibility calculations, allowing asynchronous processing of visibility and display operations. We analyze two different types of hardware-based point visibility algorithms and address the problem of bounded calculation time which is the basis for true real-time behavior. Our results show reliable, sustained 60 Hz performance in a walkthrough with an urban environment of nearly 2 million polygons, and a terrain flyover.

More Info

Funding: Austrian Science Foundation  under contract no. P-13867-INF
EU Training and Mobility Researchers network (TMR FMRX-CT96-0036)
Contact: Peter Wonka, Michael Wimmer, François Sillion
in cooperation with iMAGIS - Grenoble
Keywords: Visibility preprocessing, online visibility, occlusion culling, visibility culling, occluder fusion, real-time rendering, urban walkthroughs, urban environments, real-time simulation


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