This isn’t necessarily a metahuman question specifically so much as a question about normals and tangents
I edited some of the morphs (blendshapes), and added my own, of a Metahuman head, in Maya. I re-exported everything back to UE 5.5 so I can still use it as a Metahuman rig. All that works fine.
However, I’m noticing that there’s a very strong distinct line where the head and body meet. It’s clearly a normals issue, though it’s independent of the textures.
On the left is the original Metahuman, with smooth transition
On the right is my version of the head with tweaked morphs.
I’ve tried all the variations of import and export settings I can think of, including trying to copy over the vertex normals from the original head. I’ve tried having UE import normals /tangents, or create them. I’ve tried a soft edgeloop at the bottom of the head in Maya, or hard edges. I’ve tried removing the materials altogether. I’ve tried removing the blendshape in Maya altogether.
It’s clearly a normals issue. Unlocking the normals in Maya doesn’t actually seem to help. I unlocked, then softened edges: no fix. I hardened the edge at the bottom just to see – no difference. No matter what export settings I have, using either the Game FBX exporter (in Maya) or the default FBX exporter – no change.
No matter my import settings for UE - recompute normals + tangents, import, using both legacy and the new interchange importer – nothing seems to make a difference.
Hi Neyl_S, thanks so much for the response and suggestion! I have tried transferring normals, yeah, with no luck. That particular script I had not tried but gave it a shot this morning - it actually just uses the same method I’d tried (but also deletes the history, which is necessary for that sort of transfer but also kills the skin bind)
So sadly that’s not the fix
But thanks for responding!
Hi if you were using metahuman bodies from bridge, there is incosistency in vertex normals between source files and files from metahuman creator uploaded directly to engine.
In order to fix this, it is best to get the body and head from UE where vertex normals are correct and transfer them to target meshes, but there is some maya trickery to do before. What I do before vertex normals transfer is select the target mesh, unlock normals on it, then, harden them, then smooth, then average, clear history and NOW transfer vertex normals. After transfer I lock normals.
