generate a matte for object inside a refraction

[agnes_io]

Hi,

I have a refractive object, liquid, glass, whatever, and have objects sitting inside this. I'd like to get a matte for these objects, but the normal object color masks do not see inside/through refractions. Is there any way to generate a matte pass for these objects?

Cheers!

[ceen]

I am interested in this as well. Any solution?

[Gleitfrosch]

funny, i stumbled across the same problem over the weekend... if there was a solution it would be awesome!

[frankmci]

You can still do it the old-fashioned way and put a luminous material on the objects in question, then render a pass in the dark. It can be pretty quick, since only the specular rays need to have significant depth.