I designed the skull in Solidworks. I don't have a ton of images from this part, and surface modeling is a giant can of worms that I'm nowhere near good enough at CAD to properly explain. I got most of my help from the Solidworks Surfacing Bible, which can be purchased here
. If you're interested in my methods, take a look at the attached Solidworks file.
I did the CAM setup in CAMworks. This was divided into a rough area clearance, a z-level, and a constant stepover finishing pass. I chose to do the rough clearance with a 1/2" hogging end mill, the z-level with a 1/2" regular end mill, and the stepover with a 1/4" ball end mill.