For the next STORM seminar, Wilhem Barbier will give a presentation titled: BVH updates on the GPU using adaptive treelet restructuring

Abstract: Bounding volume hierarchies (BVH) are a widespread acceleration structure that can answer raytracing, visibility or other geometric queries in logarithmic time. However building a bounding volume hierarchy is a costly operation which is an issue for real-time rendering of animated scenes, since rebuilding the BVH from scratch every frame is not feasible and simply updating the bounding boxes without changing the tree topology can lead to degradation of the tree over time.

We introduce a novel approach to update bounding volume hierarchies for animated scenes on the GPU. We strive to maintain a high-quality BVH in a fraction of the full rebuild cost. To do so we build upon the treelet restructuring algorithm [1] which improves an existing BVH by rebuilding small subtrees (treelets) in parallel. However, instead of taking treelets that cover the whole BVH as in previous works, we sample only a small number of treelets that are expected to benefit the most from the restructuring. This focuses the computational effort on only the parts of the BVH that are degraded, which is more efficient, but raises new issues: how to sample treelets and how to handle conflicts between treelets. We will discuss our solutions to those issues and the tradeoffs that they involve.

[1] Tero Karras and Timo Aila. 2013. Fast parallel construction of high-quality bounding volume hierarchies.

This seminar will take place on Friday 14/04 at 12:45pm in room Salle des thèses at IRIT.