Hi, guys. Funny thing. I looked at the original gladiator suit and it seems to not have b__R_Forearm__ vertex group AT ALL. For some reason it seems to be merged with b__R_Elbow__.
So when you deleted some areas and joined the gladiator suit with a nude body, you introduced b__R_Forearm__, but then imported the blend file back in the package that does not have that vertex group at all.
This type of distortions usually happen when a new vertex group is added that the original meshgroup that is being replaced did not have.
The original package actually has 2 meshgroups, so that is not really the issue, but since you need a package that already has b__R_Forearm__, it's best to clone something else.
1). Delete s4studio_mesh_1;
2). Select a face on each arm, press Ctrl L to select the whole uv islands;
3). In UV editor enable sync and deselect the bracelet;
4). In 3d view press Delete and choose faces;
5). Select the bracelet and separate it ( P- Selection);
6). Unfold rig, make top visible and selectable;
7). Switch to Edit mode, select arms of the top, press Shift D, then Esc, then P - Selection;
8). Select top.001, Shift select the bracelet, switch to Weight paint, choose Transfer weights, then By name, then choose Clean with All groups selected;
9). Then join arms, the bracelet and the gladiator costume together;
10). The mesh is chopped up in some places, which will be noticeable in CAS. Use Tools - Remove doubles with Merge distance set to 0,0001. Remove doubles in the UV editor as well ( Select everything with A, press W, choose Remove doubles, set Merge distance to 0,0001);
11). When you were deleting some parts of the original, many vertices were left behind. It's best to always end with Mesh - Clean up - Delete loose;
12). There were gaps in certain areas which I removed;
13). The Sims 4 shades all meshes as smooth, which creates dark shadows along sharp edges. For it to shade these edges as sharp, you need to split either the uvs or the mesh. What you choose will give different results. When you import the blend file in The Sims 4 studio, it splits the mesh along uv island borders, which removes some of these shadows. But if the edge loop is very sharp ( close to or below 90 degrees), it's best to split the mesh yourself. Anyway, what I did was select everything in UV editor and Uvs - seams from islands. This marked the edges that s4s will split. The I cleared some of them in places where edges are not that sharp. Then I selected the remaining ones ( select one, Select - Select similar - Seam) and split them ( Mesh - Edges - Edge split);
14). Change the cut number to 0000, save;
15). Clone ymBody_EF10Noctis. The gladiator costume comes with shoes and so is this item. Beside that, it is made of 1 meshgroup. However, this item has no skirt vertex groups while yours has them. Since your garment is not affected much by them, you can just delete them. This should be done before you split the mesh because vertices may get different values despite sharing the same coordinates. After deleting vertex groups, make sure to normalize ( Weight paint - Normalize All) them. And before normalizing them, make sure the garment has Armature modifier added to it and rig assigned. After that import your blend in the package started from ymBody_EF10Noctis.
Here's a new
blend and
package files. I did not edit the textures though
