This was a prototype for a new kind of painting software that would mimick natural painting media in a sophisticated way. It would use specially designed input devices that created more natural paint data and was more comfortable to use.
Nathan Shedroff: Information, Interaction, and Visual Design, Production
VirtualPaint had controls for setting minute paper, media, and surface characteristics. Much of Fractal Design Painter 4.0 now does was designed into VirtualPaint.