Ok. let’s blame the material and make a skin material from a source that somewhat works.
Download and open the DigitalHuman sample project
Within it, migrate the skin from the bust. it’s a rather complex material and you need to simplify it.
Mine is customized beyond recognition at this point. however the important part is the settings you get on the material.
Surface, Masked, Sub Surface Profile, SSP_TwinBlast_Skin_Bust profile.
Tangent Space Normal should be checked (default I believe).
Along with the base noodle mess.
The important parts to keep are the Pores, along with the fernel mask, and the high end normal that get placed in.
To this material you will take the UV, and the Normal and “Derive Tangent Basis”, outputting the result into “tangent output” node.
This is the normal map Before the pores and the additional changes are processed.
Macro normal, normal strength, and mask modulation should be following it.
Personally, I convert textures to texture parameters, name them, and manage them in the instance so that I have a “master material” to go back to.
this is how your model looks with my test material.
This is the material i placed on it (not my default master skin)
This IS my master material, with a bad normal map for your unwrap (that’s someone’s neck beard :P)
As you can see the seam, is on top of the arm. or near where the actual seam is.
This is generated by a normal map that isn’t meant for the model.
PS:
in Digital Human you have M_Head and M_Bust.
Derive stuff from M_Head as it’s a bit more simple of a material.