The edge volume heuristic - robust triangle subdivision for improved BVH performance

The use of axis-aligned bounding boxes is a basic technique to accelerate geometric algorithms as for example ray tracing. It is a known problem that efficiency suffers, if the axis-aligned bounding volume contains major parts of empty space, which, in the case of ray tracing, causes more ray-object-intersection tests than required. The impact of this problem can be reduced by subdividing triangles at the cost of a larger memory footprint. We present a subdivision algorithm that is designed to generate only very few additional triangle references. Compared to previous approaches the algorithm is numerically robust, and simpler to implement and use. For formerly problematic scenes a speedup of up to a factor of 10 could be achieved, while the number of triangle references increased only by 16%.