Spatial Splits in Bounding Volume Hierarchies

Abstract

Bounding volume hierarchies (BVH) have become a widely used alternative to kD-trees as the acceleration structure of choice in modern ray tracing systems. However, BVHs adapt poorly to nonuniformly tessellated scenes, which leads to increased ray shooting costs. This paper presents a novel and practical BVH construction algorithm, which addresses the issue by utilizing spatial splitting similar to kD-trees. In contrast to previous preprocessing approaches, our method uses the surface area heuristic to control primitive splitting during tree construction. We show that our algorithm produces significantly more efficient hierarchies than other techniques. In addition, user parameters that directly influence splitting are eliminated, making the algorithm easily controllable.