For the flseh/armature, you can put volume with voxel sculpting, i don't know if you are really aware of the voxel
aspcet

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video voxel Well it would make sense if you animate your model, but Zbrush is not an animation tool, finally you will deliver a static model, so until they add animation features on Zbrush, i don't see it like an incredible thing

The day Zbrush will put :
- animation (they could , caus you make the skeletton and put volume on it with Z spehers 2
- Add hard volumes sculpting : create simple 3D meshes, with standard extrude face tools , cut etc ...
That day Zbrush will be the ultimate tool !