Multiple .vrmat materials exclude each other

[prima_commerce]

Version we are using is:
2025.1.2 (Build 2025_1_2_ab649993acfa Win)
V-Ray 7 for Cinema 4D, Hotfix 1 (v7.00.01 from Jan 22 2025)

Currently we are trying to export materials from 3ds Max as .vrmat and load them into Cinema 4D via VRayVRMat. Apart from bump/displace effect (which I am aware is being implemented), the procedure seems to be straightforward.

There's 2 parts of the issue which might be connected:
1. every time you open Cinema file you have to relocate (press Open folder icon etc.) the location of the .vrmat file. It's not that it gets deleted, it's says the correct location but you just have to reopen it to work. This is in itself is just annoying and not really the big issue, but...
2. when you put in a scene two (or I guess more than one) VRayVRMat materials with .vrmat, they kind of "overwrite"/exclude each other - the 3d view might even show both materials in the scene (although it also seems pretty random), but if you try to render the scene (in either VFB or Cinemas Picture Viewer) it will either show one or the other material, not both. As far as we can tell it will show the last one that was refreshed, reopened (from first part of the issue).
I have attached an image, in both views one vrmat is on the cushion and one is on the rest of the chair.

We've tried reexporting vrmats, different vrmats, different computers, different folder locations, node and class versions etc.

[deyan.hadzhiev]

Hi prima_commerce, from your description of the issue, it seems the problem might be caused by duplicated material names from the exported material from 3dsMax. Can you provide a bit more context about your problem:
1. What is the version of V-Ray for 3dsMax you are using for exporting the materials?
2. Are you using a single vrmat containing all materials from the Max scene or you export to separate vrmat files? And do any of those materials share nodes?
3. Can you provide such example .vrmat files?
4. Are there any warnings or errors in the V-Ray for Cinema 4D console log when you have both materials in the scene and you render?

[prima_commerce]

Yeah, no problem:
1. 3ds max 2025.3 a vray 7 Hotfix 1 (7.00.04)
2. We've tried both, from different 3dsmax files, single and multiple materials in one vrmat and they don't share nodes.
3. Example here: https://we.tl/t-jIEMDTc5Yf (sorry the psd files make the zip over 140mb)
4. Yes, there is a warning, for vrmats brought in after the first ones, in the style of: Warning : Bitmap file "Stratos_15x15_basecolor.png" failed to load: error reading file:2: The system cannot find the file specified.

Correct me if I'm wrong, but we have a working theory of the problem now, when exporting vrmat, all the textures used are copied to the folder where a vrmat is saved. Problem seems to appear if not all the vrmats used in a scene (and their textures) are not in the same single folder. Probably something to do/or connected with exporter stripping the actual path of the textures and just duplicating it in the same folder.
I tried to examine the vrmat file in a text editor, but honestly I'm not that good at programing and didn't have the time to blindly test all the possibilities and combinations of locations and versions to see what works.

Our quick idea of a simple solution would be when doing a "final" version of the vrmat file, we then copy it and all the textures it uses (at the same time we avoid and duplication of names of assets) into a single folder where every vrmat is copied (all colors, all fabrics, woods etc.) and then load those vrmats when using them in Cinema.
Although hat seems like using a hammer instead of a scalpel.