rig make human model one time, and make many versions of new character from one rig. Right now, it looks like every time I want to change character ...like add more faces or take away faces, I have to rig all over again.
You can only change the geometry , but you can not add more faces .
you know It is called morphing .
I know what you want to do , but it will not work. :D
of course You can increase the poly count(subdivision like zbrush), for to have more geometrie and sculp more details for the normal map or better grip for shaping, but at the end, you must this transfer in the the Low Poly Version back.
Therefore is it not necessary to import a rig (Bones), also not possible
Only the mesh is needed.
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liebe Grüße vidi