The goal of this project was to automatically generate a mechanical computer.
Furthermore, it should...
...compute something useful,
...be made to order, and unique to each person,
...and emerge from the 3D printer pre-assembled, ready to run.
Sure, um, no problem.
The first major obstacle: Using 3D modeling tools
Let's put it this way: I can build something in a 3D modeling package, just like I can eat my breakfast using only a hammer. I won't starve, but I sure don't want anyone looking over my shoulder while I'm doing it.
I'm a software engineer, but there's no way I'm comfortable enough in a package like Maya or Blender to build a custom computer made of gears.
...still, the process was ultimately successful (you can play with the 3D model here), so the rest of this instructible will be an outline of what was involved.
(See the attached PDF for an interesting short description of the final machine)