i was helping a friend with an issue similar to this and it turns out the 3d importer in roblox studios was actually messing up the normals (it flipped both the back faces and the split normals of the certain parts on the model), this issue is new to me and i don't really know the exact cause of it yet but it was fixed by checking invert negative faces in the file geometry option when importing. I will make a video on it if i find an exact reason on why it happens.
i was helping a friend with an issue similar to this and it turns out the 3d importer in roblox studios was actually messing up the normals (it flipped both the back faces and the split normals of the certain parts on the model), this issue is new to me and i don't really know the exact cause of it yet but it was fixed by checking invert negative faces in the file geometry option when importing. I will make a video on it if i find an exact reason on why it happens.
Based kaiju
thx a lot ! i've been wondering for so long why does this happen and how to fix it. it was very helpful !