SATO: Surface Area Traversal Order for Shadow Ray Tracing

We present the surface area traversal order (SATO) metric to accelerate shadow ray traversal. Our formulation uses the surface area of each child node to compute the TO. In this metric, we give a traversal priority to the child node with the larger surface area to quickly find occluders. Our algorithm reduces the pre-processing overhead significantly, and is much faster than other metrics. Overall, the SATO is useful for ray tracing large and complex dynamic scenes (e.g. a few million triangles) with shadows.