Hello all,
I have to say that it also exists something called Sculptris (owned by pixologic too)
It is free to use and download and has an interesting story...

pixologic.com/sculptris/

https://www.quora.com/How-is-Sculprits-different-from-ZBrush

Btw, Blender has also something called DynTopo, which generates geometry on-the-fly too.

Good evening to everyone!

D.