I cannot work out why the glasses I have in my scene are coming out black in areas of glass overlap, particularly when enclosed in an area which also has a chrome background.
Any ideas ?
Thanks.
Looks like you need to increase the “Max depth” of the reflections and refractions in these glass/chrome materials. Try something like 10 or 15. Otherwise Vray traces just a few reflection/refraction rays and then stops. Then it just paints the further depth with wathever is your “Exit color” (which is black by default). Hope this helps!
Thanks but I already tried that, with no joy 
Do you have “Override depth” (in global switches, expert mode) turned on by any chance? If yes, try turning it off. I can see that you actually have some champagne glasses that render fine (on the table at the far left-hand side of the example image). Can you try applying the same material? Another thing you may try is to see if the glasses have the options “Visible in reflection” & “Visible in refraction” turned on in V-Ray object properties.
Most of the glasses are filled with liquid which material also needs to be adjusted.
It would be better to set the Override Depth value globally to something like 20 and see if the results gets better or not.
No, there is no liquid inside those glasses and I tried all of that, the issue is that the glasses are in the cabinet…
Take the glasses out and put them on a vray-plane (with mirror behind etc etc) and there is no problem.
Put the glasses on those glass shelves and in that cabinet and we have those dark areas.
No idea.
Screenshot of the material settings?
I fixed it guys - thanks Macker, it was a setting in the materials which had been unchecked (not me, but a freelancer I took on, he said he’d spent 2 hours trying to figure it out…).
Sorry for any inconvenience.
Glad my advice was of help haha!
Sorry for reviving this old topic, but I wanted to add something useful.
I had a very similar problem and tried all kind of changes in the glass material and rendering settings, but in the end I found out that the problem is caused by the mirror material behind the glasses - it had a low Reflection depth ( 3 - which for most scenes works fine).
As soon as I increased the Reflection depth of the mirror (to 10 in my case) all of the glasses came out just fine.
Hi Jez
I am having this problem now, i have a bar scene with glasses but the glasses that are overlapping are rendering black, i already tried to use color only, color + alpha, and all channels, i also increased the max depth to 25 but same result. what exactly was the setting that was “unchecked”? thank you very much