If you want something similar than ZBrush or 3D Coat (for modeling polygonal subdivision) but "free" take a look at Rocket 3F!

Very cool Interface (like Moi ;)

And it has a direct "bridge" between Moi3D and Rocket 3F in the 2 ways!
https://moi3d.com/forum/index.php?webtag=MOI&msg=8092.101