Multi bounding volume hierarchies for ray tracing pipelines

Abstract

High-performance ray tracing on CPU is now largely based on Multi Bounding Volume Hierarchy (MBVH) trees. We apply MBVH to a fixed-function ray tracing accelerator architecture. According to cycle-level simulations and power analysis, MBVH reduces energy per frame by an average of 24% and improves performance per area by 19% in scenes with incoherent rays, due to its compact memory layout which reduces DRAM traffic. With primary rays, energy efficiency improves by 15% and performance per area by 20%.