options for "canvasses" without foreground cutout?

eyet33th

the concept of canvases is very useful, giving you the ability to render different parts of your scene separately. however, it seems that in providing lots of advanced options like depth maps and canvasses for individual lights and whatever, they have left out some rock-simple options. what i really want is the ability to render different objects separately, while still having the rest of the scene raytraceable. so for instance, if i have a mirror with someone standing in front of it (between the mirror and the render camera), i want to be able to render the full mirror with the reflection of the person, with the person themselves not visible in the render. as it stands, if you put the mirror in one canvas and the person in another, when you render the mirror canvas you only get the parts of the mirror that the person doesn't block.

does anyone have any techniques for this? i could go the route of deleting/moving objects out of the view for different parts, but that is very tedious and time consuming, and it wouldn't allow those figures to be visible in raytracing (so they wouldn't show up in reflections/refractions/etc). any ideas?

Richard Haseltine

If it's possible via Light path Expressions (LPEs) you should be able to do it in Canvasses.

Neko1967

Did you figure this out I am facing it now standing in front of a mirror