How I've seen it work in the past, it'll totally work with GI (and more generally, raytracing). If the frame to be rendered is CPU bound rather than I/O (becaus

How I've seen it work in the past, it'll totally work with GI (and more generally, raytracing). If the frame to be rendered is CPU bound rather than I/O (because of heavy scenes), the whole project would be farmed out to the works, so they have a full copy of what's to be rendered, then resize which part of the frame to be rendered by them. Normally this would happen locally, and if you have 8 CPU cores, each one of them get responsible for a small size of the frame. Now if you're doing distributed rendering, replace CPU core with a full machine, and you have the same principle. Obviously doesn't work for every frame/scene/project, only if the main time is spent on actual rendering with CPU/GPU. Most of the times when doing distributed rendering, CPU isn't actually the bottleneck, but rather transferring the necessary stuff for the rendering (project/scene data structures that each worker needs).