transparent material with no shadow?

[andy.engelkemier]

I sometimes have to show an object volume in a scene. Ideally I would have that object have zero contribution to GI or Shadowing. Is there a way to get that in Keyshot without having to render multiple times, and without using Interior mode (too slow on my computer)?

Toon would be ideal, xray is pretty close, but both cause interior shadows. So if an object is inside the volume, it's black. Correct? maybe, but that's not what I'm after. I'm looking for a way to cheat in order to save me time.

Right now I have to render the scene alone. Render a low quality version with the volume placed, but turn on Clown passes so I can get a selection. Then render the volume all by itself. I can then use the clown pass to create a mask for the volume and composite that over top of the original scene. So that's 3 renders, for what could just be one. If I was going for something photorealistic, that's not unusual for me. But this should just be a quickie.

Anyone have a trick for this? Are there some advanced settings somewhere that let me adjust lighting contribution for objects?