5.Adjust axis and resize.
Import to Mixamo
Remove green color in Photoshop
Rebuilt in Photoshcan
Put skeletal mesh and animation into Unreal, and added the physics environment.
About the UV mesh, the right way to draw it is following the real path on the skin in 3D space
About filling the whole, the advanced way to edit the whole is called “dynamesh” in Zbrush.