[Maya] UV unwrapping is a tangled mess and driving me mad

Fluffy_hug_of_death

The first issue I had was when I was cutting UV's there was a part of my model where 2 shells that had been completely cut, just would not split apart and sat on top of each other as one shell.
I thought I fixed this by changing my preferences folder, to "old preferences". The 2 UV's were splitting apart.
Now this is happening!
There are 2 shells that are twisted/tangled.

UV unwrapping is driving me a MAAAAD!
Please help.

Issue 1 (overlaying shells that sit on eachother).

Issue 2: twisted shells

throttlekitty

Is this joint welded? If so, that's going to create non manifold geometry, and probably part of the reason it's not cutting or unfolding properly. You're also missing some cuts on the smaller polys facing us.



For issue two, I'm not sure what your problem is with the first/large twisted shell, that looks like it should unfold properly. -but I can't quite tell which part you're showing there either.

StormyBA

Its well worth starting off with a planer map UV on anything you unwrap to get rid of any seams that maya may have auto generated. Seems to fix a few issues here n there.

Fluffy_hug_of_death

throttlekitty said:

Is this joint welded? If so, that's going to create non manifold geometry, and probably part of the reason it's not cutting or unfolding properly. You're also missing some cuts on the smaller polys facing us.



For issue two, I'm not sure what your problem is with the first/large twisted shell, that looks like it should unfold properly. -but I can't quite tell which part you're showing there either.

By Joint do you mean the entire shelf/floor area that is highlighted in the image? If so this is connected to the wall of the building, I didn't realise this would cause an issue. Is it because of the hole in the center and the lip?
I have certain edges that seem to be "permanently cut" they wont sew together in the UV tools, otherwise I would have the UV border edge at the perpendicular wall to floor corner.

The second issue, the UV larger shell is the very base (not highlighted sorry), I can see how I didn't show this in the best way, but its the base floor area surrounding the lightbulb, and the walls perpendicular to this floor. I hope that explains? I'm having the same issue with the smaller shell highlighted in the second image though, which I have left a preview of the model attached to.

I don't know anyone else who gets twisting UV's!

Fluffy_hug_of_death

StormyBA said:

Its well worth starting off with a planer map UV on anything you unwrap to get rid of any seams that maya may have auto generated. Seems to fix a few issues here n there.

Thanks! I'll try that, maybe starting off like that will get rid of twisting too?
There does appear to be auto generated seams that just are not deleteable!
I don't understand why I can't delete them though

throttlekitty

"permamently cut" uv seams is either from geometry that is unwelded, or one face has reversed normals, or non-manifold in some way. Here's a quick example of two ways geometry can be nonmanifold, I pulled the faces away a little bit to show the shapes. The T-shaped plane is welded at the joint, meaning the surface breaks continuity; no matter what, one face will be facing the wrong way. The cube has a face in the middle, which gives us the same problem, we'd likely have trouble attaching a UV seam at several places here. -Or if it is a solid UV seam, Unfold is going to have a fit because it can't decide which way to unfold opposing faces, so it likely fails and spits out a twisted result.



Since I don't know what's all going on in your model, something like this is my guess as to why you're getting weird results on those two shells.

Fluffy_hug_of_death

throttlekitty said:

"permamently cut" uv seams is either from geometry that is unwelded, or one face has reversed normals, or non-manifold in some way. Here's a quick example of two ways geometry can be nonmanifold, I pulled the faces away a little bit to show the shapes. The T-shaped plane is welded at the joint, meaning the surface breaks continuity; no matter what, one face will be facing the wrong way. The cube has a face in the middle, which gives us the same problem, we'd likely have trouble attaching a UV seam at several places here. -Or if it is a solid UV seam, Unfold is going to have a fit because it can't decide which way to unfold opposing faces, so it likely fails and spits out a twisted result.



Since I don't know what's all going on in your model, something like this is my guess as to why you're getting weird results on those two shells.

That makes a lot of sense!
Thank you so much for explaining that! Really appreciate

Alex_J

I've had issues several times with Maya's Unfold3d plugin misbehaving. After a bit of frustration, I switched to an application caleld UVlayout that plugs in to Maya and works like a charm. You can use a trial version free for like 90 days. It really makes UV's fast and easy. 

The only version of Maya that I have found to always consistently unfold UV's as expected is 2015. But I hate not being able to use a lot of the convenient features available in the newer versions.

Axi5

BIGTIMEMASTER said:

I've had issues several times with Maya's Unfold3d plugin misbehaving. After a bit of frustration, I switched to an application caleld UVlayout that plugs in to Maya and works like a charm. You can use a trial version free for like 90 days. It really makes UV's fast and easy. 

The only version of Maya that I have found to always consistently unfold UV's as expected is 2015. But I hate not being able to use a lot of the convenient features available in the newer versions.

If they don't work it's usually because there's something wrong with your mesh as throttlekitty has pointed out

When have they not worked for you?