These STL files were created from a SketchUp model on Google 3D warehouse:http://sketchup.google.com/3dwarehouse/details?mid=63a428e39db417b9106b3048633eca78From the description:"Produced at the Center for Biomolecular Imaging at Wake Forest University Health Sciences. used a CT scan of the head and segmented the bone of the skull. acknowledgements to Drs. Stitzel and Link."The model was printed on a BotHacker 3D printer (RepStrap). Read more about the print on this BotHacker blog post:http://bothacker.com/2010/05/18/printing-skulls/Printing this model is a challenge due to severe overhangs. In particular, if you print the skull upright almost the entire bottom surface has no support. Unless you have a machine that can provide support, printing it probably won't be pretty.To address this problem, we decided to print the skull in two parts: a top and bottom. The bottom part is flipped so that the cut plane becomes the bottom layer, and the top part remains upright. Since the skull is hollow each part is basically a hemisphere. This configuration is still a challenge to print, and will likely have some problems at the top. Fortunately, the defects will be on the interior of the model.There are still a number of smaller overhangs with this configuration, but we found that they can be cleaned so that they become largely unnoticeable.