Matte Reflections and Multi-Subs

[gilpo]

Was doing some compositing testing for an upcoming project and ran accross a possible bug.

Here is the base scene. The window is all one object (not grouped) and is textured with a multi-sub material. All materials are vraymtl.




I right-click the window, go into vray properties, turn on matte. Alpha contrib -1; shadows and affect alpha are on.



Notice that the glass no longer reflects as it is supposed to.

Now, I detach the glass from the rest of the window and make it its own object. I also instance out the glass material from the multi-sub and make it separate and assign it to the glass. Both the frame and the glass have the same vray properties as the image above (matte checked, -1 alpha contrib; shadows and alpha checked)



Now that's better. All I have is the reflections in the window but the glass and the frame are matted, which is what I want. In theory VRay should realize that part of the material is reflective and part isn't and render out the matte reflections properly. It seems as though that because part of the object isn't reflective, that is overrides the part that does reflect.

Is this a bug or is there some other way to make this work? It would be nice not to have to build my buildings around this 'feature'.

Thanks in advance,
Matt

[Da_elf]

not sure whats not working for you. i choose a max window object and used the multi-subobject material to texture it. made the glass part as a reflective surface using vray material then put that vray material into a material wrapper and it worked fine for me. oh re-read your post. your using the vray properties to se the matte. try just using material wrapper

[gilpo]

Yeah, I forgot to put that in my post. I was able to get the mtlwrapper to work. It's just that in that particular situation, the vray properties doesn't work, which to me, is a bug needing reported. The way we set our scenes up, sometimes it's easier to use the vray props than the mtl wrapper.

Thanks for the follow-up, though.


-Matt

[Da_elf]

did you try putting the entire multi-subobject material into a wrapper? im not infront of my system right now to try but maybe its just that the matte properties cant cope with a MSO material on a whole. each material needs a seperate wrapper

[vlado]

This has been reported before, but unfortunately, it cannot be made to work. V-Ray can extract the reflection information for matte objects only if the top material is a VRayMtl. Otherwise, it would be better to use the VRayMtlWrapper.

Best regards,
Vlado

[gilpo]

That's what I needed to know. Thanks for the response.

-Matt