I’m new to mesh deformation and I just rigged this fish in Blender ( The rig is completely functional in blender ) But when I import it into Studio the mesh completely messes up.
This is what its supposed to look like
This is what it looks like when imported to studio:
I agree with @Kullaske, I believe that this is also an issue on Roblox’s side and not yours. Although I do suggest messing with the options of the mesh, may or may not fix it.
If I had to guess, it looks like when the mesh is imported into studio, the bones get straightened out to make a flat line (instead of a curved line like in blender), and that’s why the middle of the mesh is flattened, but the head and tail is curved upward, as the bones in the head and tail are curved down a bit in blender. Maybe try to straighten out the bones in blender, and if you have to visually straighten out the mesh as well, do that, and see what happens when you import it into studio again.
I’ve never made meshes with bones before, but it’s my best guess as to what is happening.