GPU Ray Tracing of Triangular Grid Primitives

Triangular grid primitives are a technique used to handle memory-intensive meshes more efficiently. They are also referred to as micro meshes in recent proprietary hardware implementations. This representation can reduce the memory footprint during ray tracing of subdivision surfaces or displacement maps that may result from mesh simplification. This paper presents a novel approach to accelerate GPU software ray tracing using a two-level bounding volume hierarchy (BVH) to store vertices in a non-redundant manner. The primary goal is to make the technology more accessible by focusing on standard GPU devices. The bottom-level BVH strictly follows the subdivision recursion, allowing for the side effect of rendering intermediate recursion depths. Our approach enables us to encode geometry and BVH using approximately 6.3 bytes per triangle, reducing standard representations by a factor of 4.5. Additionally, the construction time of the BVH is reduced. Our data structure achieves a peak performance impact of 16 % for a three-level subdivision.