My friend Rob Flickenger recently had some dental work done - and managed to score a 3D model of his skull generated from a panoramic x-ray as a bonus.
The model looked great - but I was a bit worried about some overhangs - specifically the teeth. One option was to turn on "support material" in Makerware's slicer - but that adds print time - and removing the support material can be a painful process.
The first few small-scale prints we did came out surprisingly well. It seems you can get away with some pretty tricky overhangs as long as the distance to the nearest surface below isn't too far. The first layer or two of the overhang ends up "drooling" - and kind of turns into an unintended support.
Rob did some clean-up and manually added a few small supports using MeshMixer.
The final full-size print took 10.5 hours.
The skull was printed in PLA at a speed of 110mm/s.
As with all longer-prints - I covered my build platform with blue tape and then wiped it down with alcohol. For whatever reason - the alcohol makes the PLA stick to the tape fiercely - and virtually eliminates any concerns with curling / peeling. The downside is that the tape usually tears up when removing the model (but re-applying tape is much preferable to a failed print).
I did the time-lapse video using a cool little utility - Webcam Timelapse.