If you're asking about the fascia mesh, I might do a little step by step on how to make that. But here's the overview:
Basically I take the skin model, and delete areas like the ears, inside of the mouth, eyes.
I take that model into MeshMixer and use their fill function (it's really good)
MeshMixer only exports triangles, but I need quads because I'm going to use nCloth to shrink.
So I bring the filled fascia into mudbox and retopologize.
In a fresh Maya scene I combine all the muscle and bone geometry into one object and convert it to an nRigid.
Then I convert the fascia exported from Mudbox into nCloth and use a negative value in the pressure attributes. (Our cloth doesn't have this)
Play a few frames and the fascia nCloth conforms and relaxes over the muscles bones nRigid.
It won't be perfect first time. You have to do a few passes of shrinking the cloth and retopologizing before it looks right.
Once you have the mesh looking right, you get rid of all the nCloth stuff ofcourse and just keep the mesh. This is the final fascia mesh that gets solved with our cloth solver.
That's the gist! 🙂