First things first...

Divide and conquer.

The project has to be divided into manageable parts.

The Cartesian Box (central to project but details are dependent on the tools to be incorporated) is often scaled down for cost reasons to a particular tool requirements. But we need a box of sterner stuff for this project. How stern will affect geometries. This means that basic issues such as which axis has the tools attached and which/if an axis is locked onto another axis will have to be decided later rather than sooner.

The Tooling Interface will divided into control signaling, power, resource attachment and support resources. For example, a spindle can receive on/off, direction, speed control signals. The spindle is a motor and must receive power. The spindle has bits and must have an acceptor/chuck. Depending on use, the spindle will need cooling. This also includes items such as coolant to the material based on tool.

The World Interface is what the device expects to receive from the "world" and what it expects to give back. The device would receive power, control signals, tool elements, resources for product, Desired Output Product and waste.

The Internal Environment is the world in the box. The four basic elements of earth, wind, fire and water can be the generic label for what it manipulates inside.

These are just a few of it's favorite things.