MJP - Sounds kind of lame if I can't instance geometry and have it have a matrix. IE if I have instanced geometry I have to tranform all verts into world space for each instanced mesh and load those into Embree. Even for non-instanced geometry, when I export it, it still has a transform applied to it so that its positioned in the world properly.
Hodgman - Yea can't do it that way because of the cavities/indoor. Plus that doesn't really work well in outdoor forests either. If you have a few close boxes, but they are under a ton of tall trees, then it will get no direct lighting at all because leaves will cover every one of those depth buffers, so I have to start at the object and go out just like SSAO.
BTW, I did get it down to 1.8 mins just by getting rid of my "preview" where I show the output to the screen for each camera to see it working in real time.