NVIDIA / Weta Digital

(a) Hairball rendered with motion blur. (b) Number of intersections tests for the classic BVH with node interpolation. (c) Number of intersections tests for the MSBVH (our approach). Figure 1: The hairball consists of moving strands that are tessellated into many small triangles. The false color images depict the number of intersection tests for primary rays, where blue corresponds to small numbers and red to large numbers. As compared to the classic BVH with node interpolation, using an MSBVH, the number of intersection tests can be significantly reduced. This leads to an overall performance improvement. When a bounding volume hierarchy is used for accelerating the in-tersection of rays and scene geometry, one common way to incorpo-rate motion blur is to interpolate node bounding volumes according to the time of the ray. However, such hierarchies typically exhibit large overlap between bounding volumes, which results in an in-efficient traversal. This work builds upon the concept of spatially partitioning nodes during tree construction in order to reduce over-lap in the presence of moving objects. The resulting hierarchies are often significantly cheaper to traverse than those generated by classic approaches