Highpoly ZBrush UDIM workflow?

wenglish

Hi,

I have been learning about UDIMs lately and find them really helpful for texturing complex highpoly models with a lot of separate parts. However I am having a little trouble wrapping my head around how to deal with them when it comes to heavy ZBrush sculpts.

Substance painter can paint some really heavy models without any issues, and I can create decent UV layouts in ZBrush with UV master. The issue I'm having is that these UVs are of course placed in the 0-1 tile, but I would like to move them into their own tile so I can keep them separate in Painter.

I'm guessing that the best way would be to retopologize the mesh and rip a displacement or normal, but since I working on static meshes and am rendering still frames that seems like overkill.

I guess what I'm looking for is a way to offset uvs in ZBrush. Or maybe I'm barking up the wrong tree! Sorry if it's a stupid question, and thanks!

musashidan

Zbrush is weird with udims. It works by polygroups and you can't view them in multiple tiles or at the same time in UV space. It seems that they're all stacked in 0-1 but they're not. It's just the way ZB does it. It also has it's own udim tag. You can't set them up in ZB so you will have to do that elsewhere.

Import your model with udims already setup and got to polygroups>UV groups. This will assign PGs to udim tiles.

Now you have to isolate each polygroup(udim) and do the usual process of exporting textures from polypaint. This must be done with each polygroup in turn. You can think of it like in Substance Painter(each udim is a texture set)

wenglish

Hey @musashidan, thank you for that explanation! But I think I didn't explain what I'm after very clearly. I haven't been using polypaint. (although the information you shared will definitely save me some trouble in the future)

The issue I have right now is that I have some heavy ZBrush sculpts that don't have any UVs, either because I created them directly in ZBrush or because I didn't unwrap the basemesh beforehand. I would like to texture these highpoly meshes in Substance Painter, and I would like to unwrap them in ZBrush but have them be on their own UDIM in Painter. UV master gives me workable layouts most of the time but because of the density of the mesh offsetting them in a traditional modeling app like Maya is just really slow and usually crashes it.

Is there any solution other than full retopology of my sculpt? Since these models do not deform and are going to be rendered offline there is no other reason for retopology.

Thanks for your help!