Optix 2.5 released

A few days ago, Nvidia has released OptiX SDK 2.5 RC1 which stands out compared to prior releases due to a number of major improvements:

- out-of-core GPU ray tracing: scenes can now exceed the amount of available GPU RAM (up to 3 times)

- HLBVH2 support (Garanzha and Pantaleoni): replaces the previous LBVH builder and is able to build the BVH acceleration structure on the GPU at a fraction of the time it would take a CPU, which allows for completely dynamic scenes by rebuilding the acceleration structure each frame in real-time (e.g. the HLBVH2 paper reports building times of 10.5 ms on a GTX480 for a model consisting of 1.76M fully dynamic polygons). HLBVH2 traversal speed is said to be comparable to a CPU built BVH

This will greatly benefit real-time GPU path traced games and animations as it not only reduces the BVH build times by several orders of magnitude compared to CPU builders, but also eliminates costly per-frame CPU-to-GPU transfers of the updated BVH (when built on the cpu)

- the SDK path tracing sample is enhanced with multiple importance sampling