Objects in scenes originally made with the CPU renderer not rendering until I change their materials

[Alex_M]

I've noticed a strange bug that crops up in almost every interior scene made originally with the CPU rendering engine. The walls of rooms don't render until I make a completely new VrayMtl material and assign it to these objects. The objects still generate GI and reflections, they are just invisible. This is odd since the original materials of these objects are very basic - just a VrayMtl with diffuse color which should be no problem for the GPU engine.

Please see the screenshot below. Is this a known bug? Let me know if you need scenes.

[hermit.crab]

Do send the scene via the contact form so we can take a look. Mention me in the subject and include a link to this thread in the message.

[Alex_M]

Ok. I've created a new support ticket that includes some scenes. The ticket number is: 345-590-3253

[hermit.crab]

Thank you for the provided scene. This is a known bug (internal bug-tracker id: VGPU-5009), Sometimes, instanced materials (or multi-subobject materials) propagate object properties (such as "Visible to camera", as in your case with Object429). Simply apply a fresh VRayMtl to that object and the issue should disappear.

[Alex_M]

Got it. Thanks! Is this problem related to the fact that the scene was originally made with the CPU renderer and then switched to GPU? Does this happen with scenes made from scratch with the GPU renderer? I guess what I'm trying to say is do I need to always be on the lookout for this bug or just when converting "CPU scenes"?

[hermit.crab]

No, it just concerns GPU rendering only.

[Alex_M]

Sorry, maybe I wasn't clear enough. I meant to say will this bug appear even if I create a scene with the GPU engine from scratch, without using or importing any materials from CPU scenes? Or will it happen only with scenes that were originally made with the CPU engine which are later rendered with GPU? I'm asking so I can figure out how to restructure my workflow to avoid this issue (if possible). Thanks!

[hermit.crab]

It does not matter if the scene was created on V-Ray CPU initially. The issue will occur only when rendering on the GPU.

[Alex_M]

I see. Thanks, Aleksandar!

[labulle]

I've just run into this exact same bug in the latest Vray 6 Update 1.2 update, I guess it's still there!