SharpConstruct is a 3D modeling program designed to paint depth on
to polygon models in real-time. Unlike traditional modeling programs,
SharpConstruct makes it easy to model organic shapes. There is no
need to even look at a wireframe (unless you want to). Instead, the
model is manipulated much like clay - push or pull an area, smooth
it, make a hollow or a hill. The entire process is both simple and
organic; you won't need years of modeling experience to create
detailed models in SharpConstruct.

WWW: http://sharp3d.sourceforge.net/