Painter 3D
Note: Painter 3D is no longer available!
I would be very surprised if it's ever re-released.
Loading Nozzle Libraries Tutorial
Basic Brushes for Painter3D (Mac/PC)*
Painter 3D PC to Mac AppleScript File Conversions*
PC Models to Mac AppleScript File Conversions
* also works for Painter 4/5/5.5