We have a character wearing glasses. In the AO pass the glass lens shows up as solid rather than transparent, even when “work with transparency” is checked on in the VrayDirt texture. How can we make the class transparent in our AO pass we we can see the character’s eyes behind them?
Which vray build are you working with? How are you making the occlusion? from extra texture pass? if I assign a transparent vray material to my test object it shows up as transparent in the extra tex layer, as I would expect. You can also make it as a part of exlusive set in the dirt so it does not cast or receive any occlusion.
If I remember correctly you can use extra tex + on glass material apply in reflection/refr(cant remember which one exactly) affect all channels.
Vray 2.3 (the latest version I believe). The AO pass is an extraTex with vrayDirt. The glasses are not “transparent” via the opacity, but through the refraction with affect channels set to “all”.
I’m not sure what “on glass material apply in reflection/refr” means, can you clarify?
“but through the refraction with affect channels set to “all”.” you already did it. So I’m out of ideas fro the moment. I’m off to bed. Good luck ! 
Thanks, bye.
you might want to try a 2.4 build. With that one if you just lower the opacity it shows correctly in the extra tex element. Alternatively you can just make a custom render layer and do the occlusion pass that way.
Has 2.4 for Maya been released?
its a part of development in the nightlies, you should request chaos for the access.