I’m having a hard time with Backburner and the UDIM tag in the VrayBitmap loader.
I’m a CGI teacher, my students sometimes work at home, sometimes at school. Problem: they have to relink manually each UDIM set of textures in the Asset Tracking Toggle each time they switch from a computer to another. Unfortunately, if a UDIM set is missing, it’s not found in the User External Paths added in the Project paths configuration.
I almost found a solution: using scene-relative path for UDIM textures, with the textures folder near to the scene file location. It works well locally, but not with Backburner (even with the include maps option checked: the UDIM maps are successfully collected and added to the job archive, but then are separated from the scene file, so relative paths don’t work anymore).
I’m considering switching to distributed rendering for next years, but is there some solution with Backburner for now? Is it normal behavior that missing UDIM textures still ignore alternative user paths?
As a last resort, we’ll use the MultiTile node instead of the Vray loader (it works with alternative user paths, but then color management becomes quite touchy, as we have to set the color setting for each UDIM tile!).
I tried archiving the project (File > Archive) to collect all the assets, afterward I opened the file and placed the new External Path (Customize > Configure project paths), and it seems to work fine for both local and backburner renderings. No need for relative paths or the “include maps” option. Can you try it out?
I just tried what you said.
Initially, my UDIM path is set locally, on the desktop. Something like C:\Users\…\Desktop\mytexture.<UDIM>.jpg
If I make the archive and open it, the textures are found locally in the initial desktop folder. At that point, if I remove the textures files in this initial desktop local folder, the texture are missing, even without rendering on Backburner. The textures should be found in the subfolders near to the scene file, right?
Let’s try the external paths, I add a path to the network, available for all servers *(*something like \\10.1.104.250\schoolNetwork\Textures). The files remains missing if I render the scene (still without Backburner).
I try to add an external path pointing on a local folder containing the textures, they’re still not found
I think there is a problem at this point - even without trying to render the scene with Backburner.
In your test, is the backburner server running on the same computer you use to setup the scene? That could explain why the files are successfully loaded (they are found locally, neither in the job archive, nor in the external paths).
I didn’t understand if you added the network path to the 3ds Max external paths.
Yes, I did try Backburner locally, but I double-checked where the files were taken from (by adding/removing the external path).
Yes. I also tried placing the UDIMs on a UNC network path, added it to the external paths in 3ds Max, and stripped the bitmap paths. It works fine.
Overall, this does not sound like a V-Ray issue. Does it happen with non-UDIM textures? Does it happen with f.e. Arnold? Which 3ds Max version are you using?
Also, I would suggest trying a mapped cloud drive (like G-drive) instead, which should avoid this kind of conundrum.
Yes, I did. I use 3ds Max 2026.3.2 with Vray 7.20.08.
It is related to Vray, especially to the VrayBitmap using UDIM tags. Its behaviour in case of missing texture is very different from regular textures. It doesn’t happen with the native Multi-Tile node, or with regular VrayBitmap textures.
Please let me explain again, in a simple test without Backburner or network paths. I just sent you a zip file with the scene and the textures.
It works fine, as expected (the right side of the viewport is IPR, not Nitrous viewport).
Then, I move my textures in another folder on the desktop. I add a new external path pointing to this new folder like this (added at the bottom of the list):
Look at the render: the textures are missing. Don’t look at the viewport or the material editor, the textures are cached and are still visible, but at render time they are missing.
Then, I try to move my textures at the root of my scene…
The UDIM tags in the VRayBitmap texture are resolved on demand while rendering. This is done on purpose to avoid loading all tiles if they are not going to be actually needed. At the moment it is not possible to call the 3ds Max asset management code to resolve the texture paths during rendering - which leads to the problems you are experiencing. This is different from the Multi-Tile node which loads and resolves all textures in the beginning of the frame.
It might be possible to fix this, will need to look into it.
Ok, thanks! Maybe we could have an option in the Vray settings to force loading all the UDIM tiles at runtime, similar to what the MultiTile node does? Or, like you say, resolve the paths at render time, if possible.
Until this, we’ll stick to the MultiTile loader for UDIM textures. Especially with Backburner, who doesn’t throw an error message in case of a missing VrayBitmap UDIM texture. Too risky in our context (CGI students short films, with many many shots, assets & textures)!
Please let me know if something changes in the future about this, thank you!
