Hi,
It seems that vray_mtlselect render pass isnt working right? I put vray material with dirt in diffuse slot into vray_mtlselect parameters material slot and when I render I get black render with alpha in the alhpa channell? why I cant get dirt in there?
Another problem is that I cant drag any material from meditor to vraymtlselect material slot and neither viceverse. I think this is a bug?
You need to have the material applied to something in your scene. VRayMtlSelect only extracts this material from the image and puts it in its own layer.
Render elements in V-Ray can only extract information that is computed during the normal course of rendering calculations; they cannot show information that is not in the rendering.
Best regards,
Vlado
I see. now its works fine. drag drop bug is not the big problem sience u can select the materials from meditor dialog
anyways. I was looking for extra pass for ambient which I made with dirtmap. but if I need to add this dirtmap to all scene objects then I can use mtl override and just output the ambient pass.
What is the use of mtlselect? what is the difference of mtl override and mtlselect then?
I think you misunderstood the purpose of Mtl_Select. It is not meant as an alternate Material Element, but it is meant to isolate a specific material in a seperate renderelement. That way you can render out an extra element that contains only the objects that have the materials applied.
Regards,
Thorsten
yea. I was just looking something handy 
now this is very clear.
thanks! 