Can't get matte shadows to work through glass

[dougie]

As title says.

What happens is that I can't get the shadows of other objects to show up in the alpha channel (on the surface where I use the vraymtlwrapper) when the shadow is behind an object with glassmaterial applied. It works in rgb but not in the alpha.

I use VRayMtlWrapper with the following boxes checked: Matte surface, Matte for refl/refr, Shadows and Affect alpha. I have set Alpha contr. to "-1".
Have tried with Brute force and IM.
I use a domelight with a HDRI as only lighting. I have also tried with a vraysun with/without vraysky. Same result.

WHAT am I missing?

*edit*:
I'm using V-Ray 3

rgb
alpha
white background applied in PS
settings vraymtlwrapper
settings glassmaterial

[Svetlozar Draganov]

Which is the exact version of Vray 3.0 that you are using ?
It works on my side when Affect All Channels is activated for the Refraction Layer of the transparent object.
For some reason matte-objects is visible in the refractions (alpha is OK) but this won't be an issue. Since Affect All Channels option is activated I won't need refraction render element in compositing stage - all needed information would be distributed over other render elements like GI , Lighting , etc.



And here is a simple compositing and background-change in Nuke:

[dougie]

Thank you very much!
I used 3.05.03 and installed the 3.05.04 today.
Suddenly I could not reproduce my error and started looking at the settings for the glassmaterial. It seems the problem was that I for some reason had chosen All channels in the Affect channels rollout in the reflection settings. When selecting "Color only" it works like a charm.
Since I installed the latest build I don't know if this was enough to make it work in the 3.05.03 build. But probably.

I don't know - staring at things (settings) for too long makes you blind I guess.

Again - thank you!