Hi
Simple and weird thing. If I render object with Glossy refractions,
it won’t show transparent alpha.
-Create box
-Assign V-Ray mat -refr 200 -Glossiness 0,9
Affect Alpha on
-Render
Alpha of box is totally white.
Is there something I don’t understand or is this some really stupid thing
how VRay works? 
Max 2008 VRay 1.5 sp2
-LarsSon
Objects with refraction dont contribure to the alpha anyway, I just put my glass materials inside a vraymtl wrapper and set the alpha contribution to -1.
But if I have material Glossiness set to 1, alpha looks fine.
Only anything under 1 will turn alpha to full white.
Sorry, misread your post. Does this happen even when using an override? What if you right click the object, go to vray properties and set the alpha contribution to -1 there?
Unfortunately V-Ray does not at this time support the “Affect alpha” option for glossy refraction (it never has, for that matter).
Best regards,
Vlado
Okay, thanks for info.
So is there any plans to support it or any workarounds?
Nowadays when we do a lot of product visuals too, sometimes
it’s really needed option. I know it’s because optimizing renderings, but
that should be option to choose. If needed, I’m ready to go
fully bruteforce way to get the best or needed results.
-LarsSon
Well, it is implemented now for SP3, actually.
Best regards,
Vlado
heh, nice one Vlado 
now this sounds great as i always had the same problem with the aplha map to be opaque. i understand that it’s difficult to render out the appropriate alpha behind glossy materials. after more than 5 years we get it, cool =)
ale
Hi there,
I was just wondering if this is still the case? 5 years since this post and Affect all Channels for Glossy Refrations is still not supported? (using Maya, VRay 2.40).
Thanks,
Ben
In 3ds Max, this is implemented since a long time as I mentioned above. I’m not sure about Maya, I need to check.
Best regards,
Vlado
Unfortunately it is not ported to Vray for Maya - Alpha channel on objects with Refraction Glossiness different than 1.0 is always pure white color (1,1,1)
We have that issue into our system but it is not fixed yet.
Hi there,
I have found a kind of workaround but it is not proving ideal, I wonder if you could offer any ideas on how I could further improve our workflow here as we are quite reliant on the glossy refractions in Alpha on one particular project.
The solution is to use the ‘BRDFVRayMtl’ rather than the standard ‘VRayMtl’.
The problem is that we cannot achieve the same result using ‘like for like’ settings between the ‘BRDFVRayMtl’ and the ‘VRayMtl’.
Would it also be possible at all to using the standard ‘VrayMtl’ and only use the ‘BRDFVRayMtl’ as a Refraction override on the shader as we have been unsuccessful in getting that to work.
Any input appreciated.
See my reply in the other thread.
Best regards,
Vlado