Refracted Mutli-Sub Object material doesn't render correctly

[dennisqdw]

So here's the problem. I've made a glass bottle that has a "wall" meaning thickness. If I make a refractive (and reflective) glass material and apply it then the bottle renders correctly. If I make a multi-sub object with the same material in both slots, selecting the outside faces of the bottle as material 1 and the inside ones as material 2, then the bottle doesn't render correctly. I can't see why this should make any difference at all. I've attached two images showing the difference. I can upload a max file if you need it.
BTW even though I subscribe to my posts here, I don't seem to get notifications. I don't think it has to do with a spam filter or anything. Any ideas?

thanx --ds

[hermit.crab]

I cannot seem to replicate the issue on a simple scene. Could you send the max file to support@chaosgroup.com for further investigation? Mention your software versions and this forum thread in the e-mail.

Regarding the notifications - check your accounts notification settings in the user settings.

[hermit.crab]

Thank you for the provided files. The bug is reproducible, however, it is already fixed in the latest nightly builds.

As a workaround fill both Multi/Sub-object material slots with a single VRayMtl, rather than two copies of a VRayMtl plugged separately.

[dennisqdw]

Thanx I'm glad to hear that you folks were able to fix it. Actually, although I showed you the bug with 2 of the same material, the actual reason this came up is that the "outside" material originally had a slight displacement that the inside one didn't have which is why I had to make it a multi-sub in the first place. So unfortunately your workaround wouldn't work in this case. Are the nightly builds considered to be stable? Would I be able to download it at some point and check it out? yours --ds

[hermit.crab]

My bad - the issue has not yet been fixed (i forgot to turn on the mtl ids version of the edit poly when testing), however, it is a known one and our developers are informed about it.

What you can do is to use a single glass material with a VRayMultiSubTex set to 'Face material ID' for its displacement. For the parts without displacement set a solid black VRayColor texture.

I'm attaching an illustration of the sample setup.

[dennisqdw]

Ok, I'm leaving town for a couple of weeks, and I'll test this when I return. Thanx for keeping on top of it. I'll get back to you then. --ds

[dennisqdw]

Ok, just got back to this. Yes that's a clever workaround, that does work. However, there are minor differences between this fix and the glass without the multisub. Although it happens that I like how the "fixed" version looks. If anyone else with the same problem reads this, they might want to know that. If you, Aleksandar, want to follow-up with me on the minor difference let me know, but I'm ok with calling this issue resolved. Thanx for your help. --ds