Visibility preprocessing for interactive walkthroughs
Proceedings of the 18th annual conference on Computer graphics and interactive techniques
Hierarchical Z-buffer visibility
SIGGRAPH '93 Proceedings of the 20th annual conference on Computer graphics and interactive techniques
SIGGRAPH '93 Proceedings of the 20th annual conference on Computer graphics and interactive techniques
Portals and mirrors: simple, fast evaluation of potentially visible sets
I3D '95 Proceedings of the 1995 symposium on Interactive 3D graphics
Real-time, continuous level of detail rendering of height fields
SIGGRAPH '96 Proceedings of the 23rd annual conference on Computer graphics and interactive techniques
Temporally coherent conservative visibility (extended abstract)
Proceedings of the twelfth annual symposium on Computational geometry
Real-time occlusion culling for models with large occluders
Proceedings of the 1997 symposium on Interactive 3D graphics
Visibility culling using hierarchical occlusion maps
Proceedings of the 24th annual conference on Computer graphics and interactive techniques
View-dependent simplification of arbitrary polygonal environments
Proceedings of the 24th annual conference on Computer graphics and interactive techniques
Accelerated occlusion culling using shadow frusta
SCG '97 Proceedings of the thirteenth annual symposium on Computational geometry
A market model for level of detail control
Proceedings of the ACM symposium on Virtual reality software and technology
Hierarchical geometric models for visible surface algorithms
Communications of the ACM
VRAIS '97 Proceedings of the 1997 Virtual Reality Annual International Symposium (VRAIS '97)
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In this paper, occlusion testing in very large virtual environments is discussed from two perspectives: a theoretical one, discussing occlusion culling in relation to detail elision (level of detail), and a practical one, relating to an adaptive occlusion-culling algorithm developed in this paper. The theoretical perspective formally demonstrates the efficiency of detail elision in the face of real-world-like environments. It further shows the utility of using detail elision not only to lower the triangle count of individual objects but also to lower the load on the scene graph traversal algorithm. Finally, the results indicate that, even in open environments, one needs occlusion culling and that approaches based on choosing only a few good (convex) occluders are insufficient in this case. Practically, the theoretical perspective is reflected in the development of an occlusion-culling algorithm based on a marriage of the frustum-slicing approach to view frustum culling and hierarchical occlusion maps (HOMs). The resulting algorithm is much simpler than the original HOM algorithm, requires little pre-processing, and integrates detail elision with the occlusion-culling algorithm in a natural way. The approach is well suited for use with large, complex models with a long mean free line of sight (“the great outdoors”), models for which it is not feasible to construct, or search, a database of occluders to be rendered in each frame. The algorithm is tested for such large models, and results show that frame rates tend to converge as the geometrical complexity of the model increases.