Parallel Spatial Splits in Bounding Volume Hierarchies

Abstract

Bounding volume hierarchies (BVH) are essential for efficient ray tracing. In time-constrained situations such as real-time or large model visualization, fast construction of BVHs usually compromises hierarchy quality, resulting in reduced rendering speed. We propose a parallel framework for the state-of-the-art BVH construction algorithm with spatial splits (SBVH) that provides highest quality hierarchies within a time frame competitive with lowquality builders optimized for construction speed. We leverage both data and task parallelism to employ threading and single instruction, multiple data (SIMD) capabilities of modern CPUs. Our key contribution is a lightweight memory management and load balancing scheme that maximizes parallel efficiency.