To model the underskull for my 3D Printed Animatronic Robot Head I used the open-source software Blender to create a shell which encloses the internal mechanisms. This project was an exercise as I wanted to use as many different CAD programs as possible to broaden my options.
The skull was designed as two halves so that if I needed access to the internal mechanisms I could just take off one side instead of disassembling the entire thing. Blender has a great animation feature built into the software so I could check my moving parts inside the skull and ascertain whether any pieces would intersect. You can watch a video of the printed animatronic head in action below.