Watertight Ray Traversal with Reduced Precision

Published: 06/10/2016, Last Updated: 06/10/2016

By K. Vaidyanathan, T. Akenine-Möller, and M. Salvi
Intel Corporation

Reduced precision bounding volume hierarchies and ray traversal can significantly improve the efficiency of ray tracing through low-cost dedicated hardware. A key approach to enabling reduced precision computations during traversal is to translate the ray origin closer to the bounding volume hierarchy node after each traversal step. However, this approach precludes sharing of intersection computations between a parent node and its two children, which is an important optimization. In this paper, we introduce a novel traversal algorithm that addresses this limitation and achieves a significant reduction in the computational complexity of traversal compared to previous approaches. We also include an analysis that shows how our algorithm guarantees watertight intersections which is a key requirement for robust image quality, especially with reduced precision traversal where numerical errors can be large.

Attachment Size
rptraversal.pdf 3 MB

Product and Performance Information


Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804