While implementing my acceleration structures for cudart ray tracer (more on this in another post) I have been reading other papers / research in the field. Some of the results / implementations are very impressive with decent framerates at a high resolution and a lot of primitives in the scene.
What I did notice is that in all these demos / screen shots they tend to move the camera around while nothing in the scene moves. So although they are all using various types of kd-tree type acceleration implementations they never actually need to recalculate the tree between frames. In a scene with a lot of objects moving at once (games for example) this kd-tree restructuring becomes non-trivial.
I think the realtime ray tracing community really needs to come up with some decent reference scene with movement in order to compare improvements in future. The days of the static bunny or cornell box no longer provide enough information as to the realtime performance of the raytracing and acceleration algorithms.