Instant Visibility

Peter Wonka, Michael Wimmer, François Sillion
Instant Visibility
TR-186-2-01-16, September 2001 [ paper]
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Replaced by Wonka-2001-Ins.

Abstract

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.

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@techreport{Wonka-2001-IV,
  title =      "Instant Visibility",
  author =     "Peter Wonka and Michael Wimmer and Fran{\c c}ois Sillion",
  year =       "2001",
  abstract =   "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.",
  address =    "Favoritenstrasse 9-11/186, A-1040 Vienna, Austria",
  institution = "Institute of Computer Graphics and Algorithms, Vienna
               University of Technology",
  note =       "human contact: technical-report@cg.tuwien.ac.at",
  month =      sep,
  number =     "TR-186-2-01-16",
  keywords =   "visibility, occlusion culling, urban visualization,
               real-time rendering, parallel visibility",
  URL =        "http://www.cg.tuwien.ac.at/research/publications/2001/Wonka-2001-IV/",
}