Retopology works the same in Modo and I have heard it also works that way in Silo. You simply click here and there and the system creates polygons for you, trying to align them as good as possible to the mesh in the background. This can be whatever you put into the background layer.

I also like the idea to use voxels. It has more power than sculpting texture maps or polygons because it can create new geometry wherever you want. And you dont have to care for mesh loops, edges, vertices whatever unless you start your retopology session.

But all this makes only sense for creating organic models. Architectural design works better with good old extruding, shifting, boolean, and so on.