### Abstract

In this paper we propose a novel visibility-culling technique for optimizing the computation and rendering of opaque isosurfaces. Given a continuous scalar field f(x) over a domain D and an isovalue w, our technique exploits the continuity of / to determine conservative visibility bounds implicitly, i.e., without the need for actually computing the isosurface f ^{-1} (w). We generate Implicit Occluders based on the change in sign of f* (x) = f(x) -w, from positive to negative (or vice versa) in the neighborhood of the isosurface. Consider, for example, the sign of f* along a ray r cast from the current viewpoint. The first change in sign of f* within D must contain an intersection of r with the isosurface. Any additional intersection of the isosurface with r is not visible. Implicit Occluders constitute a general concept that can be exploited algorithmically in different ways depending on the framework adopted for visibility computations. In this paper, we propose a simple from-point approach that exploits well-known hardware occlusion queries.

Original language | English (US) |
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Title of host publication | Proceedings - IEEE Symposium on Volume Visualization and Graphics 2004. VolVis 2004 |

Editors | D. Silver, T. Ertl, C. Silva |

Pages | 47-54 |

Number of pages | 8 |

State | Published - 2004 |

Event | Proceedings - IEEE Symposium on Volume Visualization and Graphics 2004. VolVis 2004 - Austin, TX, United States Duration: Oct 11 2004 → Oct 12 2004 |

### Publication series

Name | Proceedings - IEEE Symposium on Volume Visualization and Graphics 2004. VolVis 2004 |
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### Other

Other | Proceedings - IEEE Symposium on Volume Visualization and Graphics 2004. VolVis 2004 |
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Country | United States |

City | Austin, TX |

Period | 10/11/04 → 10/12/04 |

### Keywords

- Computational geometry
- Graphics hardware algorithms
- Isosurfaces
- Marching cubes
- Occlusion culling
- Visibility computations
- Volume visualization

### ASJC Scopus subject areas

- Engineering(all)

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## Cite this

*Proceedings - IEEE Symposium on Volume Visualization and Graphics 2004. VolVis 2004*(pp. 47-54). (Proceedings - IEEE Symposium on Volume Visualization and Graphics 2004. VolVis 2004).