Hello. I'm making this a separate post from my previous question since I think it's become a whole can of worms. I'm making a helmet that works with simtanico's scalp sliders. I only want to preserve the vertex ID(from vertex IDmod) of the scalp. However, I merged the scalp, face, and neck parts in order to have a seamless look for my helmet. I think this was the step that ruined the vertex ID of the whole mesh. In the blender sims 3 geom tools, the "transfer GEOM data" tool lets you to combine 2 geoms together, but I got an error when I tried it.

So I exported it as an object, converted it to wso, and then assigned my bones and morphs in MTK. I imported it into TSRW and exported it as a package. Then I opened the package in S3PE to export the geoms and morph geoms. In the MTK's auto assign vertex ID section, I assigned original AM face/neck geom to my base geom first and then used the vertex ID mod scalp to "replace only zero vertex IDs." This works so far as when I load it in game, the sliders work with the helmet.

I converted the morph BGEOs to geom using the base geom with the reassigned vertex ID. Then I imported them all in blender to edit each morph. Once I was satisfied, I exported them all. With the package still open in S3PE, I replaced the lod0 of the helmet with the base geom, saved and exit. Then I used MTK's package tools to add my new morphs to the package. I saved as a new package and tested in game. The sliders still work, but the morphs don't. If I skip all of the vertex ID transferring and just renumber the whole mesh, the morphs work but it not longer works with the scalp sliders.

I attached pics of it in blender, in game, and the error I got from the blender geom tool. The highlighted part of the mesh is the section I'm trying to preserve IDs.

Is it possible to get these 2 things to work at the same time? I would manually assign each vertex ID if there's a way

The "helmet" you show in the first pic, looks to be more than just the EA scalp? If so, it won't work. That piece will have more vertices than the EA scalp, so ID numbering won't match up. As for morphs, the scalp doesn't morph. Open a bald hair in TSRW and cycle the morphs. The scalp area doesn't move.