topic Use world space? in Intel® Embree Ray Tracing Kernels

Use world space?

theigors — Thu, 13 Jun 2013 12:33:50 GMT

Hi All

Is it make a sense to build embree accel structs in world space and convert rays/poinrs from camera to world before cast rays? Many scenes are built as "more aligned" in world space. so at least in theory a better data ballance/division can be achieved. Did anyone try and what is an effect?

Thanks

In ray tracing you by default

SvenW_Intel — Fri, 14 Jun 2013 05:14:52 GMT

In ray tracing you by default build your acceleration structure in world space, to take advantage of aligned geometry as you point out. This further has the advantage that one can move the camera without having to rebuild the acceleration structure. To get best performance pass world space geometry to Embree.

My tests don't show

theigors — Thu, 20 Jun 2013 12:43:52 GMT

My tests don't show significant speedup for room scene (attach)

- 3:33 world space
- 3:38 camera space

Your camera view is almost

SvenW_Intel — Fri, 21 Jun 2013 05:15:46 GMT

Your camera view is almost axis aligned, thus it is not surprising that you do not see a big difference. If you rotate the camera by 45° you should see a performance degragation.