topic Problems with UV Unfold and Non-Manifold Geometry After Merging Mesh Parts - Maya in Maya Forum

Problems with UV Unfold and Non-Manifold Geometry After Merging Mesh Parts - Maya

javimartiruiz — Tue, 18 Nov 2025 15:06:44 GMT

Hi everyone,

I’m working on a low-poly character in Maya and I’m running into issues when trying to unfold the UVs, later I want to animate that model and getting it into Unity. Maya keeps warning me that it needs to “fix non-manifold geometry”, and when I let it fix the mesh, some vertices that I previously merged become separated again.

Here is what’s happening:

I merged several areas of the mesh that were visually touching ( skirt with inner legs and arm with torso.).
When I use UV → Automatic or try Unfold, Maya detects non-manifold geometry in those merged areas.
When it fixes it, it un-merges the vertices, and I don't know if that it's correct, for later animate it.

My questions are:

What is the correct workflow in Maya to avoid creating non-manifold geometry when merging parts of a low-poly character?
Should areas like the skirt, sleeves, and other clothing pieces remain separate meshes and not be merged into the body, but then I have problems with animation?
What is the recommended way to clean up the mesh before UV unwrapping so that Unfold works without breaking the merged vertices?

I want to make sure I understand the proper workflow before continuing the UV layout and rigging process.

Thanks in advance for your help!

This post has been edited due to: @heather_tracy added the product to the title to help more community members find this topic.

Re: Problems with UV Unfold and Non-Manifold Geometry After Merging Mesh Parts

Christoph_Schaedl — Tue, 18 Nov 2025 08:13:02 GMT

I assuem there is doubled geometry somehow.
If you delete one face in that area is dere a second underneath?

Re: Problems with UV Unfold and Non-Manifold Geometry After Merging Mesh Parts

javimartiruiz — Tue, 18 Nov 2025 09:06:35 GMT

No, I don't have double-sided faces. The problem is at the two points where Maya interprets this double extruded ruffle onto the geometry at the bottom of the skirt; the same thing happens there, and that's where those errors appear, but everything is joined, not duplicated.

Re: Problems with UV Unfold and Non-Manifold Geometry After Merging Mesh Parts

damaggio — Tue, 18 Nov 2025 11:49:07 GMT

You said you merged with the inner side of the sleeves, that creates illegal geometry and should not be done.

That’s why the warning appears. Either separate arms and legs or create thickness for the clothing and attach the human parts.

Re: Problems with UV Unfold and Non-Manifold Geometry After Merging Mesh Parts

heather_tracy — Wed, 26 Nov 2025 21:10:06 GMT

Hello, @javimartiruiz,

Did the information provided by @Christoph_Schaedl or @damaggio help you and answer your question?

If yes, please click on the "Accept Solution" button. This will assist other community users in finding and benefiting from this information.

If not, please do not hesitate to give an update in this thread so all community members receive an update on the progression of your question, and can suggest next steps that may be helpful for you to achieve what you're looking for.

All the best,

Heather | Community Manager

Re: Problems with UV Unfold and Non-Manifold Geometry After Merging Mesh Parts

javimartiruiz — Thu, 27 Nov 2025 09:29:03 GMT

They didn't work perfectly for me, because if I separated those vertices, it would break at those points later with the rig and animation, and I couldn't separate the mesh by clothing either because the model already had clothes on. In the end, I left everything welded as it was and made a UV auto-model, and I'm painting it like that in Substance.