That's an interesting machine - I've never seen one quite like it. The digitizing function looks fairly straightforward; the last rotates on the spindle while a wheel runs against it and slowly moves along, capturing the displacement values as it goes. I suppose it could do the same thing with a cast of someone's foot, as long as you didn't need much detail.
The digitizing probes I've seen used with Mach3 are not the same; they consist of a round-ended pin supported by springs, set so that any deflection of the pin causes it to record directional information - which way the pin moved. Here's a version that uses strain gauges for that: http://www.mdpi.com/sensors/sensors-...5-g014-550.jpg
These Renishaw-type touch probes work slower than the wheel on that machine, but they capture more information. With some programming skills, you might be able to get Mach3 or LinuxCNC (which is more open) to interface with a wheel device like that. Normally, the information captured would be fed into a CAD program to construct a 3D model, then the model used to generate a toolpath and G-code. This machine seems to take a shortcut and just replay the information as it was recorded.