Not so long ago I discovered Autodesk Inventor’s ability to sculpt a solid body using solely Work Planes. The command also nicely allows the user to select fill & drain directions for the resulting solid. The power of this approach comes with the knowledge that planes have infinite boundaries, whereas a rectangular surface boundary is not. As a result it’s a valid tool for use within parametric modelling techniques, which would ultimately improve the stability of your model.
Anyway, a video is by far the easiest way to show this, so check it out below: