Watertight Ray Traversal with Reduced Precision

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.

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