The render repeatedly fails (by fails I mean finishes but without the desired result, i.e. no caustics are present in the render).
The Output Window shows the standard "no photons stored after emitting..." message.
When I switch the material to the old mia_material, the render works exactly as it should with no warning or error messages.
I want to use the passes material, because erm.. I want to use passes.
What am I missing?