Visibility Culling for Time-Varying Volume Rendering Using Temporal Occlusion Coherence

Typically there is a high coherence in data values between neighboring time steps in an iterative scientific software simulation; this characteristic similarly contributes to a corresponding coherence in the visibility of volume blocks when these consecutive time steps are rendered. Yet traditional visibility culling algorithms were mainly designed for static data, without consideration of such potential temporal coherency. In this paper, we explore the use of Temporal Occlusion Coherence (TOC) to accelerate visibility culling for time-varying volume rendering. In our algorithm, the opacity of volume blocks is encoded by means of Plenoptic Opacity Functions (POFs). A coherence-based block fusion technique is employed to coalesce time-coherent data blocks over a span of time steps into a single, representative block. Then POFs need only be computed for these representative blocks. To quickly determine the subvolumes that do not require updates in their visibility status for each subseq...

• Type: Conference
• Year: 2004
• Where: VIS
• Authors: Jinzhu Gao, Han-Wei Shen, Jian Huang, James Arthur Kohl
• Keywords: Temporal Occlusion Coherence, Time Steps, VIS 2004, Visibility Culling Algorithms, Visualization