This image shows the final result of my thesis work. The models above are voxel models with 4096 (2^12) voxels in every axis. If they were all filled, I would have to store 4096^3 = 68719476736 voxels in total. There has been a lot of research into compressing the huge amount of data this requires, I mentioned some examples on the thesis page.
Using a Sparse Voxel Octree (SVO) storing scalar field values, the six models above can be stored in 12GB of memory total. Using my multiresolution method we can store visually comparable models in only 2GB of memory total.
Here is a small video showing the current state of the voxel path tracer: