Faster Ray Packets - Triangle Intersection through Vertex Culling

Acceleration structures are used in ray tracing to sharply reduce number of ray-triangle intersection tests at the expense of traversing such structures. Bigger structures eliminate more tests, but their traversal becomes less efficient, especially for ray packets, for which number of inactive rays increases at the lower levels of the acceleration structures. For dynamic scenes, building or updating acceleration structures is one of the major performance impediments. We propose a new way to reduce the total number of tests by creating a special transient frustum every time a leaf is traversed by a packet of rays. This frustum contains intersections of active rays with a leaf node and eliminates over 90% of all potential tests. It allows a tenfold reduction in size of acceleration structure whilst still achieving a better performance.