Vray Proxy Face IDs

[juleslin]

Hi everyone,

We are currently working on a scene that involves a significant amount of complex assets. To streamline this process, we're utilizing Vray Proxy as a source to construct the scene. The benefits of Vray Proxy are notable—it requires minimal pre-processing time before rendering and it can be scattered using the 'Copy to Points' function. However, our assets often require more than one material, so we need to determine a way to apply multiple materials to the Vray Proxy. According to the Vray online manual, Face IDs are included in the Vray Proxy, but I am not able to use this feature.

Consequently, I have a few questions:

1. How can I effectively export and import the Vray Proxy (vrmesh/abc) with Face IDs and apply multiple materials?
2. I've heard that some individuals are using Alembic in place of Vray Proxy (replacing the "path" attribute with "shop_materialPath" so the material can be predefined). The performance is purported to be on par with using Vray Proxy, but in my experience, Alembic requires an extended pre-processing phase before rendering. Is this accurate?
3. The vrscene option appears promising, yet it has many limitations.

I would greatly appreciate any insights or suggestions regarding these questions or if you could propose a more efficient workflow. Thank you for your time and assistance!

Best,
Jules

[juleslin]

I am writing to report an issue that I recently encountered while working with Vray. More specifically, the problem lies with the Vray Proxy Material's ability (or lack thereof) to process the FaceID in Vray version 6.10.09.

To provide some context, the workflow is fairly straightforward. I assign different materials to an object, export the object in vrmesh, and then read it back using the Vray Proxy Import SOP. Afterward, I create a Vray Proxy Material in matnet, fill in the path of the Vray Proxy Import SOP and then material slots appear (the number of slots is based on the number of materials assigned). Finally, I link the materials to their respective slots.

Unfortunately, my attempts to execute this process were unsuccessful due to an issue with my current Vray version (6.10.09). It appears the Vray Proxy Material in matnet is unable to process the FaceID correctly, resulting in only one material being used in the render.

For comparison, I tested this workflow in a previous version of Vray (6.00.21), and it worked as expected. I have not yet tested this in any newer versions. I would greatly appreciate it if the Support Team could investigate this issue and share their findings.

Thanks.

[bdancer]

The short answer is to use Alembic SOP/ROP.
V-Ray proxy support was basically added for loading *.vrmesh files exported from another applications.

The slightly longer answer:

> the problem lies with the Vray Proxy Material's ability (or lack thereof) to process the FaceID in Vray version

Well, no, the problem is that there are simply no face material IDs written into the vrmesh file.
Face material ID vrmesh property is generated out of specific attribute "face_mtlIDs",
if you could create such attribute and match it with your material setup - it'll be written into the vrmesh file.