Maya - I only want something to be visible thru reflection

[High1ander]

I have a thing where I render out some stuff visible in one layer, then I want to render out that stuffs relections alone in one layer so that I later can fiddle with it in AE without affecting the other layer.

So are there any settings like "make objekt ONLY visible thru reflections." I have found a couple of reflections settings and such but nothing that makes it ONLY visible in the reflected surface.

Thanks for all the help!

[Raptor365]

I read a couple days ago one guy who worked on a film was describing the rendering process. For the reflection pass he rendered one pass with reflection on and one without.
The one without he added a single light then in post he made a blending matte from that to show the reflections on the ship in the areas where the light was brightest.

Multipass in Mental Ray seems to be a pain, but if you google it there are some tutes out there for it. I saw one for maya but I lost the link, figures. Should be easy to find though.

[High1ander]

Ok, my workaround has been basically rendering out one without reflections in the mirror, then one with both the subject and the reflected mirror. Later on in AE with some tweaks I basically use one of the renders to "cancel out" (alpha matte) the subject so alone is only the reflection in the mirror. It is a pain, but it works because I don't need it to be perfekt since I only need a matte.

[oneinfiniteloop]

Multipass in mental ray is the way to go. Takes a minute to get used to, but it works well once you figure it out.

[sks]

select Window-General Editors-Attribute Spread Sheet - Then click geometry tab.

This will let you turn off Primary visibility for any objects in your scene. (So they reflect but don't render themselves)