Torn or Jagged Appearance On Skirts & Dresses

Hi. Please always provide your blend and package files. It can be weights transferred from the nude body instead of the dress of appropriate length or you could have added 3fff00 too low

Its the choice of the reference but the vertex paint is also not right.

The bottom of the dress must move and morph differently from legs, so you need to transfer all related data from a dress of similar length, not a nude body.

There are a few other things:
- your dress's polycount is 2,5 times higher than that of maxis's most complex meshes, yet it is still not shaded as smooth in the area of wrinkles, so it is high poly for nothing. These types of elements (wrinkles on clothing) are meant to be preserved through texture, not mesh, so it would be more reasonable to make a low poly version of the dress without wrinkles and then bake diffuse and normal map to it from the high poly version with wrinkles . As for making a low poly version, you should not use Decimate for lod0, it messes up the topology in a way that leads to jagged morphing and moving. Either change the topology to quads and keep Particle distance high or retopologize the mesh;
- another reason for high polycount is overlapping geometry. You are meant to delete all parts of the body covered by clothing, all overlapping parts of the clothing. They cannot be seen so they serve no purpose;
- back to the problem you came here for, for a reference you need to choose a dress of similar length, it does not matter what it looks like above the waist, just the length must be right. Then you simply transfer weights, uv_1 and vertex paint from it. Speaking of vertex paint, 3fff00 should be only in the skirt area, but you do not need to worry about it, just transfer it;



- it is best to make garments from more patterns so that you would be able to occupy the available space more efficiently