Fused BVH to Ray Trace Level of Detail Meshes

The paper presents different strategies for fusing Bounding Volume Hierarchies (BVHs) of varying level of detail (LODs). Our method makes it possible to traverse BVHs of varying LODs in a cache-friendly way for path tracing. Considering BVH of the finest level (we call it the Base LOD BVH), the method defines a strategy to fuse subtrees from BVH of other LODs to the Base LOD BVH. Our method proposes a heuristic to find such subtrees in non-Base LOD BVHs and an algorithm to find fusion or insertion points for these subtrees in the Base LOD BVH without much increasing the overall the volume of the Base LOD BVH and the number of nodes traversed as a result of this fusing.