A couple of things when working with Raytrace which I noticed and which may have already been pointed out.
A) When working with material settings from Object properties window – Detailed settings on Physically Based do not show up consistently in the dialog box…maybe a window sizing issue? It seems to work correctly in the Material Editor window when pulled from drop down.
B) Selecting an object in viewport does not cause the material selection to jump to assigned object material in the Material window.
C) It’s great to see the PBR materials. I think others have pointed out but will also add that it would be great to have an emissive multiplier based on a real world output…ie. Lumens, etc.
D) It’s important when rendering to be able to go back and continue working on a scene – is the plan to have rendering handed off to process separately allowing work to continue on a scene?
Thanks for making the WIP available…great work!