1). Your garment and the reference you cloned are affected by skirt bones while the swimsuit you cloned is not. Introducing new bones leads to this distortion you are lucky to witness in your game, a lot of creators do not get it yet people who use their cc do;
2). Your garment is made of one meshgroup while the swimsuit you cloned is made of 3. Some of them do not get overwritten and can cause more distortions;
3). No matter how good your cc looks, if it crashes other people's game or makes them wait forever for it to load, it is bad. 60k is way too much, you should not go past 10k unless absolutely necessary;
4). Scale uv islands uniformly unless they can use more definition ( buttons, zippers ) or less ( geometry created to close holes ), otherwise there will be a difference in texture quality;
5). Do not put uv islands close to the border of the uv space;
6). Transfer weight and a uv_1 map with Nearest face interpolated, otherwise it will morph and animate like cramped paper;
7). Skirt-like bottoms should be vertex painted differently, otherwise they will be affected by morphs ( thigh, calves) that skirts should not be affected by, there will also be an indentation between legs;
8). Use as a reference something that is close to yours in length. You transferred weights and uvs from something that is much shorter and the bottom part will animate and morph like legs, not skirts;
9). Never ever use Decimate modifier, it ruins everything there is to ruin;
10). Do not crank up Environmental lightening to that extent, it hides all the details you created;
11). Never ever use Make blank button, it removes maps from the file thus disrupting its structure and causing all types of issues.
Anyway, the main issue you are experiencing can be fixed by simply re-importing the mesh into a package started from DressPanels ( type that word in the search bar when choosing an item to clone ). It is made of one meshgroup and is already affected by skirt bones. That will not fix other issues ofc
I suggest you to make something extremely simple, like those water polo swimsuits or a tank top, and make it function perfectly. Starting your learning process from something complex is the worst thing you can do. Also, if you plan on making complex clothing, you should learn how to retopologize it.
The right approach to making detailed clothing is to create a high-poly mesh, retopologize it, then bake the details from the high poly mesh to low poly retopologized version.
Here is a tutorial that shows how to do that for a normal map but the same can be done for the diffuse ( or you can composition the result )
I briefly covered the logic behind retopology
here. Do not waste your time on automatic retopology because it is useless for the task at hand, especially for preserving pleats
This is how to transfer weights in 2.76-9 version of Blender
- make sure the reference and your mesh are visible and selectable;
- select the reference, Shift-select your garment, switch to Weight paint, press Transfer weights, set it like in the pic;
- use Clean tool with All groups selected;
- use Limit total.
This way you will get much better results
Use nearest face interpolated for a uv_1 transfer
This is how to vertex paint
Vertex paint dictates what variation (skin-tight and robe-like) of deformation maps the painted area will deform according to in CAS during body customization and animation.
00FF00 is for skint-tight areas, 3FFF00 is for any skirt-like area ( skirts, bottom parts of dresses, coats, aprons, etc).
Start by choosing 00FF00 and Paint - Set vertex color
1). Disable Limit selection to visible;
2). Holding Ctrl, lasso-select the bottom part of the mesh starting somewhere in the middle of the pelvic bone;
3). Enable sync;
4). Press B and deselect legs;
5). Switch to Vertex paint and enable Face selection masking for painting;
6). Type in 3FFF00;
7). Paint - Set vertex colors;
8). Press A twice to deselect and select everything again, Paint - Smooth vertex colors
