Quad-tree Expression of Bounding Volume Hierarchies for Ray Tracing

Abstract

We propose methods to construct bounding volume hierarchies (BVHs) as quad-trees which are used to accelerate ray tracing. BVH is one of spatial and hierarchical data structures that are used to efficiently find intersection points between rays and rendered scene. Generally, tree structures of hierarchies are expressed as binary-trees. However, recent spreads of CPUs which have SIMD instructions to compute data in parallel lead us to consider quad-tree expressions of BVHs. We extend two methods which have been used to construct binary-trees to construct quad-trees. By means of proposed methods, memory usage and depth of tree of constructed BVHs are reduced.