Octree-Based Sparse Voxelization for Real-Time Global Illumination

Last year Cyril Crassin presented a voxel based approach for interactively computing indirect diffuse and specular lighting, along with a couple of demonstration videos, and kept working on the matter since then.

In this talk given in May at the NVIDIA GPU Technology Conference, he briefly explains the technique:

Interestingly enough, as he points out, the technique has been implemented in the Unreal Engine 4 already.