Transparent material

Rendering
1

Is there a way to make a material in rhino transparent from one side? So you can put a plane where the ceiling of a room is and ‘see’ the ceiling when you’re rendering inside but the light from the hdri will illuminate the interior? I think this can be done in SketchUp. Can it be done in rhino?

Thanks for any advice you can offer.

2

Not with the current materials. If you don’t mind using Raytraced you could create a custom shader for that with GhShaderNodes.