Fast BVH Construction on GPUs

TLDR

The paper introduces two parallel algorithms for fast construction of bounding volume hierarchies on manycore GPUs. The authors develop a hybrid method that first builds a Morton‑code based hierarchy, then refines it with a surface‑area‑heuristic top‑down approach, achieving high parallel scalability and reduced build time. The hybrid algorithm produces hierarchies nearly as optimal as SAH while building significantly faster, enabling GPU construction to rival multicore CPUs and handle models with millions of triangles for rapid ray tracing.

Abstract

Abstract We present two novel parallel algorithms for rapidly constructing bounding volume hierarchies on manycore GPUs. The first uses a linear ordering derived from spatial Morton codes to build hierarchies extremely quickly and with high parallel scalability. The second is a top‐down approach that uses the surface area heuristic (SAH) to build hierarchies optimized for fast ray tracing. Both algorithms are combined into a hybrid algorithm that removes existing bottlenecks in the algorithm for GPU construction performance and scalability leading to significantly decreased build time. The resulting hierarchies are close in to optimized SAH hierarchies, but the construction process is substantially faster, leading to a significant net benefit when both construction and traversal cost are accounted for. Our preliminary results show that current GPU architectures can compete with CPU implementations of hierarchy construction running on multicore systems. In practice, we can construct hierarchies of models with up to several million triangles and use them for fast ray tracing or other applications.