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ZBrush Breaking UVs

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#1

Hi

I’m currently having a problem with ZBrush destroying my UVs from Maya. I’ve been following this tutorial: https://www.artstation.com/artwork/zZOOL

However, if I export my mesh out of Maya with a clean mesh, and I’ve tried with an FBX, OBJ, and MA file too, and then take it back into Maya, the UVs become broken. Fragmented. It does it if I just take the mesh straight into ZBrush and export it straight out again. Though it’s usually the overlapping UV that breaks. If I Reconstruct the Subdivisions in ZBrush based on that linked tutorial, all the UV shells become broken. :-\

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#2

Hi @DustyShinigami

ZBrush doesn’t support overlapping UVs. If your islands are overlapping in any way, this probably accounts for your issue.

:slightly_smiling_face:

1 Like
#3

Ah-haaa. Thanks for pointing this out. :slight_smile: I’ll try moving the overlapped piece, which is the back part of my clothing from an extrusion.

#4

Okay. It’s kind of helped. Taking the mesh into ZBrush and taking it straight back to Maya is fine, but if I reconstruct the subdivisions, they’re still broken a bit. The outer edges seem to detach. But not for the underside island, for some weird reason.

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#5

I will also take the opportunity to point out that ZBrush doesn’t like it if your UV islands are butting right up against the edge of the UV space. It’s usually best to make sure the islands have a few pixels of empty space between the islands and the edge of the UV space. This is another situation in which your UVs might become distorted.

Good luck!

1 Like
#6

Oh. Strange. Okay, I’ll try re-positioning them and see what happens. Thanks.

#7

Oh, sorry! You posted at the same time I did. That was a general tip and not the cause of your problem here I don’t think. Your issue here is most likely caused by attempting to reconstruct the UVs into a lower level than they were created at. Create your UVs at the lowest level of subdivision and then subdivide your way up.

:slightly_smiling_face:

#8

Oh, I see. I was going to say, the issue remains, sadly.

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Following that guide, that’s essentially what I did - constructed the UVs at a very low level and then subdivided upwards. It’s just that guide suggests reconstructing the subdivisions, so you have a low poly version with clean topology and UV(s), and so it can be taken back into Maya so the thickness that was made from the extrusion stage can be unwrapped.

#9

Just do a Ctrl+W within ZBrush to create a brand new polygroup. Then try to export it.

#10

Yeah, unfortunately, I’ve tried this as well. Usually, when I add thickness/panel loops in ZBrush, it will automatically make new Polygroups for the edges and back faces.

#11

Ctrl+W that too.

#12

I think I’ve finally solved the mystery! It’s Maya. Maya is to blame. I just tested it out in Maya 2023 and there wasn’t a single issue with the UVs. After adding panel loops, and then taking it back into Maya, the UVs were overlayed perfectly! No fragmentation. However, I did the same thing in Maya 2022 - broken. :smiley: Mystery solved (hopefully)!