We present HLBVH and SAH-optimized HLBVH, two high performance BVH construction algorithms targeting real-time ray tracing of dynamic geometry. HLBVH provides a novel hierarchical formulation of the LBVH algorithm [Lauterbach et al 2009] and SAH-optimized HLBVH uses a new combination of HLBVH and the greedy surface area heuristic algorithm. These algorithms minimize work and memory bandwidth usage by extracting and exploiting coarse-grained spatial coherence already available in the input meshes. As such, they are well-suited for sorting dynamic geometry, in which the mesh to be sorted at a given time step can be defined as a transformation of a mesh that has been already sorted at the previous time step. Our algorithms always perform full resorting, unlike previous approaches based on refitting. As a result they remain efficient even during chaotic and discontinuous transformations, such as fracture or explosion.
Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than Eurographics must be honored.