DOBB-BVH: Efficient Ray Traversal by Transforming Wide BVHs into Oriented Bounding Box Trees using Discrete Rotations
Journal:
arXiv
Published Date:
Jun 28, 2025
Abstract
Oriented bounding box (OBB) bounding volume hierarchies offer a more precise
fit than axis-aligned bounding box hierarchies in scenarios with thin elongated
and arbitrarily rotated geometry, enhancing intersection test performance in
ray tracing. However, determining optimally oriented bounding boxes can be
computationally expensive and have high memory requirements. Recent research
has shown that pre-built hierarchies can be efficiently converted to OBB
hierarchies on the GPU in a bottom-up pass, yielding significant ray tracing
traversal improvements. In this paper, we introduce a novel OBB construction
technique where all internal node children share a consistent OBB transform,
chosen from a fixed set of discrete quantized rotations. This allows for
efficient encoding and reduces the computational complexity of OBB
transformations. We further extend our approach to hierarchies with multiple
children per node by leveraging Discrete Orientation Polytopes (k-DOPs),
demonstrating improvements in traversal performance while limiting the build
time impact for real-time applications. Our method is applied as a
post-processing step, integrating seamlessly into existing hierarchy
construction pipelines. Despite a 12.6% increase in build time, our
experimental results demonstrate an average improvement of 18.5% in primary,
32.4% in secondary rays, and maximum gain of 65% in ray intersection
performance, highlighting its potential for advancing real-time applications.
