So i am trying to import a sword i made in blender into roblox studio and i imported it as a single mesh then as seperate meshes so i could colour them, but when i imported it as seperate meshes, it warps and swells to different shapes.
Are you exporting as FBX, or as OBJ groups? Try exporting as the other one…? I think this looks like a problem with surface normals, not with Roblox deforming your mesh.
Try exporting it as an OBJ instead (although you might have to use 0.001x scale - or 100x? I don’t remember which way it is). I’ve had more luck with OBJ since it’s (arguably) a simpler format that Roblox is less likely to get tripped up on. Remember to export as groups.