Figure 1: The BART robots scene (71.7K triangle, 1 quad light), rendered with primary rays only, forced 2-bounce reflections, soft shadows (16 light samples), and a 2-bounce path tracer (16 samples per pixel). Though slower than aggressive packet/frustum techniques for the primary ray case, our single-ray based method is more efficient for the less coherent soft shadows and path traced images.
ABSTRACTWhile contemporary approaches to SIMD ray tracing typically rely on traversing packets of coherent rays through a binary data structure, we instead evaluate the alternative of traversing individual rays through a bounding volume hierarchy with a branching factor of 16. Though obviously less efficient than high-performance packet techniques for primary rays, we demonstrate that for less coherent secondary ray distributions this approach is at least competitive with (and often faster than) typical packet traversal techniques.