[feynman]

I have to render a client's luminaire, using an emitter. The object looks slightly transparent, although the material has no transparency set. The exact same (cloned) material, with a different colour, renders opaque, as it should. If I put the cloned (good?) material on the object that renders slightly transparent, it renders opaque. If I put the original (bad?) material on other objects that did render opaque, they render slightly transparent.

This is puzzling, to say the least. Someone has an idea what the cause could be? Thanks!

http://i.imgur.com/J00iJlm.png

[numerobis]

I think i had the same problem some time ago (must have been v3.2.x; HDRI + emitter).
There was one opaque material that rendered transparent (from Sketchup, MXM). I rebuild the material from scratch but it didn't solve the problem. The geometry had no thickness. I ended up extruding the geometry which fixed the problem (or maybe it was only less noticable, i never checked it again).

[feynman]

I see; one can see through the USM Haller shelf panels, which is bizarre.

In my case, the objects always have thickness (double-walled) and they do render properly opaque with clones of the original material (and other materials).

The original material also renders other objects transparent, if assigned to them to test with, so I believe it must be related to the material, not the objects.

I am using MR 3.2.1.2, IBL and an emitter (in each luminaire).

[numerobis]

Now i notice that the display light (MXI) in the background and the light from the HDRI can't be seen through the shelf so it must be related to the emitter only.
Is it possible that there are problems with older emitter materials? I think i set them up some years ago - if i remember correctly.

edit: i wrote v3.2, but it must have been the latest v3.1 beta - i confused it with the v-ray versions

[tom]

Could one of you please send a simple scene with problematic material?

[feynman]

Thanks, Tom, I sent you a Dropbox link per PM yesterday or the day before. Much appreciated!

[tom]

OK, I received the scene and categorized this as a bug report. The leak/bug is about the Opacity of upper Layer which is less than 100 in Normal blend mode. Until you have a patched version, please use Additive blending in the upper layer. Thank you!

[feynman]

Thanks again, much appreciated!

[numerobis]

Sorry for the late response. I don't have the time at the moment to send the scene. It sounds that you don't need it anymore. If it is still needed i could send it next week.

If it is about layer opacity, i think my material has only one layer with two BSDFs. - if i remember correctly.

[tom]

If it is about layer opacity, i think my material has only one layer with two BSDFs. - if i remember correctly.

Maybe there are more cases... So, please send if you can. Thank you!