This is a scan of a life-size model of a human skull, which was made with an Artec Spider scanner, using Artec Studio 12 software. You will find that the eye sockets and nasal cavity are not totally accurate as the scanner cannot reach those areas. Everything else is near accurate to the original model. The mesh has been simplified from the original to keep the file size down.

EDIT: Sorry folks, there was an error in the original file. Just fixed it with NetFabb and uploaded the fixed file. Go forth and print!