As promised at Siggraph 2009, Nvidia has released OptiX, a ray tracing engine that's set to help developers speed up their ray tracing applications by utilizing a C-based API running on the CUDA architecture.

According to its maker, the OptiX engine provides applications with features like parallelism (both within the GPU and across GPUs), state of the art acceleration structures (BVH and KD trees), as well as traversal algorithms. OptiX is also supposed to be very flexible and allow devs to accelerate whatever ray tracing task they wish and run it on standard hardware.

For more info about Nvidia's OptiX and maybe even a download of the SDK check out this page.