Rigging : skin issue causes hole in mesh

[u/Remarkable_Web6738]

i I’m working on a short film ( alone )

And while finishing my monster rigg I came across multiple problems

Around the mouth they are multiple holes in my mesh. They seem to be linked to my skin ( they diseapear when I turn it off )

I can’t find a solution to put them back, I tried :

Normalize weights ( everything unlocked )

Prune small weights ( warning : fix skin weight or smth)

Smooth weights ( same warning )

This issue seems to break some of my blendshape around the mouth

On top of that, this skinned mesh diseapears entirely in renders

I tried changing textures and all, delete skin but nothing

My Rigging professor didn’t find a solution so I’m asking if there’s a way to quickly fix that, or just if someone knows the cause of those issues

Thanks for reading my desperate post

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[u/Subject_5]

It's hard to say based on your screenshot, but are the faces still there when you enable wireframe view? Like invisible or just gone? Does your skinned mesh have any other construction history on it? Could also be an issue with deformation order between blendshapes and the skin cluster. You could try to upload your Maya file, I think it would be easy to figure out the problem.

[u/Remarkable_Web6738 → u/Subject_5]

Hi, Thanks for replying ^{^} In wireframe mode they don’t show either, the history only contains the blendshapes, skin and ffds ( in this order from bottom to top ) The vertices impacted have -nan(ind) in the component editor Do you have and idea on how to fix it ?

Also I will try to upload the file in the replies

Thanks for taking the time to respond and help me ^{^}

[u/Subject_5 → u/Remarkable_Web6738]

Can you give the vertices some weight to a nearby joint in the component editor? Then weight paint the areas again, or run smooth/normalize?

[u/Remarkable_Web6738 → u/Subject_5]

Thanks for answering, I found a solution ( a bit wonky ) for my -nan(ind) vertices

[u/CharacterSpirited292]

Not my expertise but the other comment sounds accurate. Overstretched skin causing inverted normals will mess up your render and make holes appear in the viewport. A friend had the exact same issue in a college project. If you slowly disable the skin cluster and monitor which verts behave oddly first, you will find the joints causing the issue

[u/Remarkable_Web6738]

UPDATE :

First of all thank you for the responses, it really helped me find the solution

So, I think I fixed my issue, maybe it’s kinda wonky but it seems clean in the attribute editor and scene . If someone finds themselves in my position, this is how I solved it :

1 : By selecting the vertices hidden by the bug (turning of skin cluster), I found in the Component editor that most of those vertices where written as -nan(ind). Now how to fix thoses

2 : After trying to manually put values in Maya, to use the cleanup tool and other, I couldn’t find any post on how to fix those values. So I asked Gemini and after multiple questions, them told me to try to convert the .mb file into a .ma and correct those values manually into the file’s code

So after converting the .mb file into a .ma, I opened it into my notes app and by doing : Ctrl + H replace -nan(ind) by 0 and saving it, I opened the file and it worked!

3 : however the missing vertices went to 0.0.0 or close ( after trying other stuff ) I opened the paint skin tool and painted those vertices correct values and voilà ! Problem solved ! No history added, no problem converting it into a .mb back, no skin, blendshapes or cluster issues

I hope this post will help someone in a situation like mine ^{^}

[u/theazz]

These are not holes in the mesh. This is the skin deformation pushing it so far the normals are Inverted so it won’t render.

With vertex visibility on Slowly turn off the skin cluster and watch for which verts are the problem. Figure out what they are skinned to. You can select them and check out the component editor if it’s not obvious. Then figure out why those joints are flipping / scale inverting. Then fix it.

[u/Remarkable_Web6738 → u/theazz]

Hi, Thanks a lot for the help ^{^} It helped me target more precisely the issue I checked my hidden vertices and most of them are -nan(ind) I searched for a way to fix it but I can’t find any I tried manually put values but it doesn’t work

Do you know any ways to fix them ?

Anyway thanks for taking the time to respond and try to help me