As you may already know, I wanted a D20 that had "20" on each side. Shamelessly abusing my power as a blogger for MakerBot, I asked the citizens of Thingiverse to create one for me. ( http://www.makerbot.com/blog/2011/09/29/openscad-challenge-regular-icosahedron/ ) Polymaker was the first to post a solution and win the prize. ( http://www.makerbot.com/blog/2011/09/30/polymaker-dont-mess-with-him-that-dude-rolls-20s/ ) (Though, really prize might be overstating the value...)
I tried printing several icosahedrons at different sizes and resolutions, but none of them seemed to come out very well. Most of the time the extruder would snag the die and pull it off the build platform. Finally I adjusted the design a little in OpenSCAD and printed the D20.
Here's what I did:
The author marked this model as their own original creation. Imported from Thingiverse.