Having trouble with uv_1 for custom penis

[IrishHoetato]

Hey all, first time trying to make CC for the Sims 4 and I'm having some trouble with the uv_1 not correctly deforming with the weight slider. It is acting as if the mesh is splitting around the ring of the chastity cage, and there are even a few faces at the top of the testicles that are transforming. In blender these gaps are all single vertices. Getting at my wits end on how to fix this, i have no idea what is different about the vertices that are following it and the vertices that are not. I have tried manual adjustments on the uv_1 multiple times, I've tried the data transfer method from a chastity mesh by simdulgence that i noticed was deforming with the slider, I've tried following different weight painting in case it was the bones messing me up, and nothing has changed. It's always the same issue.

 

Does anyone have any tips or clues on how to fix? Most searches on uv_1 here are old posts that talk about the genitals not being allowed to scale, or related to clothing. 

 

The only thing i can recall being different about the pieces that aren't moving and those that are was that the vertices/faces originally didn't belong to "DiffuseMap" material, everything else that moves was originally belonging to that. I did assign them but that was before the issue occured. So I'm not sure if there is another assignment that is missing?

[IrishHoetato]

Found the problem, they weren't painted in Vertex Paint to color0 file, now I've got a few stray vertices moving abnormally with the slider but that'll be trailer and error until it is resolved.

 

This was the post that managed to point me in the right direction. I never noticed anything like this step in the tutorials, but i can accept I'm dumb

 

https://sims4studio.com/post/147256/thread