I haven't see such an arm in action.
So what area can the arm cover, if you imagined a plasma cutter attached to the arm? You will need to know the range of movement of each joint.
The arm axis co-ordinates are angular from what I can see. Most CAD drawings assume X, Y and Z for 3D axes. Hence some software has to translate the XYZ to the arm co-ordinate system.
If you want to move the arm 6 inches along X-axis only, how will you tell it? It looks like it has an hydraulic piston. If so how does it respond to a computer control?