UCT CS Research Document Archive

Exact From-region Visibility Culling

Nirenstein, Shaun, Edwin Blake and James Gain (2002) Exact From-region Visibility Culling. In Gibson, Simon and Paul Debevec, Eds. Proceedings Eurographics Rendering Workshop, pages 191-202, Pisa, Itally.

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To pre-process a scene for the purpose of visibility culling during walkthroughs it is necessary to solve visibility from all the elements of a finite partition of viewpoint space. Many conservative and approximate solutions have been developed that solve for visibility rapidly. The idealised exact solution for general 3D scenes has often been regarded as computationally intractable. Our exact algorithm for finding the visible polygons in a scene from a region is a computationally tractable pre-process that can handle scenes of the order of millions of polygons.
The essence of our idea is to represent 3-D polygons and the stabbing lines connecting them in a 5-D Euclidean space derived from Plücker space and then to perform geometric subtractions of occluded lines from the set of potential stabbing lines.We have built a query architecture around this query algorithm that allows for its practical application to large scenes.

We have tested the algorithm on two different types of scene: despite a large constant computational overhead, it is highly scalable, with a time dependency close to linear in the output produced.

EPrint Type:Conference Paper
Keywords:Exact Visibility
Subjects:I Computing Methodologies: I.3 COMPUTER GRAPHICS
ID Code:46
Deposited By:Nirenstein, Shaun
Deposited On:23 September 2003
Alternative Locations:http://people.cs.uct.ac.za/~snirenst/nirenstein_se_1.pdf, http://cggmwww.csie.nctu.edu.tw/seminar/eurorender/04/from-region.vc.pdf, http://portal.acm.org/citation.cfm?id=581921&jmp=references&dl=GUIDE&dl=ACM