Import/Export breaking the Vertex Groups assignments + Milkshape support?

[BrunoLiddell]

Hi! First of all, thanks for making this add-on. I downloaded it from Mod The Sims, and it still works great with Blender 4.0!

Recently I came across a clothing mesh that seems to have imported with incorrectly assigned vertex groups. The imported GMDC was exported from SimPE, and is a custom (not from Maxis) bottom mesh for Adult Females.

Here's a .blend file for you to take a look at if needed (I included a README with a short description of what is inside): GMDC_addon_BoneAssignmentsIssue.zip

To make sure this was caused by the add-on (and not some other factor) I've imported the same GMDC file into Milkshape and the assignments show up correctly. Here's a screenshot of that:

Initially I only wanted to convert the mesh for TF. I got around the issue by transferring the vertex group data from a different mesh (that properly imports), essentially redoing the bone assignments. It works, but as you can imagine it's extra work that could have been avoided. This particular mesh is quite simple, so redoing the assignments didn't take too much time either, but it could end up becoming far more difficult on a more complex mesh. Which is why I'm opening this issue.

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I have also noticed that the add-on seems to export things a bit differently. For instance, when I import a mesh from Blender using it, into SimPE, there seems to be 16 Joints missing in the "Joints" list (in SimPE). I have taken a screenshot of those as well:

At first I thought it was because they were always unassigned on the specific meshes I had worked on (body parts). But then, when importing the finished mesh I was talking about before (which is a bottom part), I saw that other Joints were unassigned, and yet were still listed in SimPE. The in-game result works perfectly well though. I'm only bringing this up in case it was an unintentional oversight or something?

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Also, I know you've said before on MTS that you didn't make this add-on with Milkshape in mind, but I was wondering if there wasn't any way to work around the problems that arise from transferring a mesh from one software to the other?

Currently, if I export a GMDC using your Blender add-on, and import it into Milkshape, the imported mesh doesn't include morphs, and some Vertex Groups seem to also be incorrectly assigned (which isn't the case in Blender).

Importing the exported file back into Blender however works correctly, so I don't know what Milkshape can't figure out in the "Blender exported" file. I personally wouldn't mind since I only use Blender, but since most modders in TS2 community use Milkshape still, it poses a bit of a problem if someone else tries to import a Blender exported mesh into Milkshape to change it in any way.

Somehow I feel like these issues most have a common denominator, but I can only assume since I don't have knowledge on how the GMDC format works exactly.

If you were up to look into these issues, it would be much appreciated! But either way, thank you so much for making this add-on in the first place! 😃