Another great 3D demo posted by Joe Beda of the Avalon team, including source code.  Looking at the code, a few things jump out.  The code is nicely componentized.  The hosting .exe references the 3D object as a control, so that you could include the control in your own projects.  And the control itself uses a class that contains several generic 3d objects, including a plane, cube, toros, sphere and cylinder, that are potentially reusable.  I haven't tried this myself yet, but plan to shortly.  The ImageBrush class is used extensively to paint the 3D surface.  The hosting .exe also uses styles in some very clever ways.  There's a lot to be gleaned here...