Help, my Uvs does not unfold proprely

Melaniein3D

Good evening everyone, I desperately need help with a problem that I have had for a while and which I cannot resolve. Every time I unfold UVs it goes wrong, either they fold on themselves or they don't unfold correctly at all. Here are the solutions that I have already tried without success: Use "camera-based" or "planar", activate the Unfold3D plugin, restart maya, checked that the edges and vertices of my objects are well merged, checked that the normal are in the right direction and reset the settings preferences. All of this did not correct the problem. I don't understand where he comes from. I am a beginner and I use the 2022 version of Maya. Thanks for any help!

Alex_J

where is the failure? it looks like the face and head unwrapped as expected.

try adding a cut down the middle of the highlighted UV shell and see how it unwraps. that should show us if the unfolder is working correctly, and if it is, then the problem would just be that you need to change how you are cutting the shell.

Melaniein3D

Alex_J said:

where is the failure? it looks like the face and head unwrapped as expected.

try adding a cut down the middle of the highlighted UV shell and see how it unwraps. that should show us if the unfolder is working correctly, and if it is, then the problem would just be that you need to change how you are cutting the shell.

I tried cutting in the middle of the head and it worked, even if the uv is not perfect at least it's not fold on itslef. I tried with the arm and the problem is still there. Maybye my mesh isn't modeled correctly. The faces are not evenly distributed I think...

poopipe

you'll often get this sort of thing on organic surfaces. 

there's a bunch of tools like relax you can use to fix the folding (relax etc.) they'll introduce distortion into the UVs but that's just a thing that happens and you need to balance it against desirable seam placement

Melaniein3D

poopipe said:

you'll often get this sort of thing on organic surfaces. 

there's a bunch of tools like relax you can use to fix the folding (relax etc.) they'll introduce distortion into the UVs but that's just a thing that happens and you need to balance it against desirable seam placement

There's no way to avoid this without making ankwards cuts? I use the relax tool constantly when I do retopology

Alex_J

So, when you made cut down middle of the skull and then it unfolded without overlap, that indicates that the tool is working correctly.

I could not explain the algorithm by which is works but you can imagine it like unfolding a cardboard box. If you do not cut all of the sides appropriately, you simply cannot unfold it.

So yes you will need to place some cuts strategically and sometimes this can mean putting a cut even in a high visibility spot. But with modern 3d texturing apps its usually not going to present a problem.

You will probably benefit a lot to look at some professional models and see how they have been unwrapped. You can check base meshes in the wiki here, there is a few to download. Also check the ones in Maya's content browser - I am not sure if they are unwrapped or not but worth a look. Other than that just search around internet, there is loads and loads of examples out there that you can look at. 

You'll probably see that a lot of times UV shells are cut up in weird ways just so that the body part can be unfolded in a way that maximizes its spread over the square area, so you get the most efficient use of resolution.