However, you have to consider what's considered quite adequate today.

Not many precise measurements are made at all, and those are "by guess and by golly" as they say, with roundoff done mentally, and so on.

Further, adjustments, i.e. intuitive changes in various dimensions are also often used to locate "features" to accommodate bony protrusions and the like, or to relieve them in cases where they cause uncomfortable contact with the socket, are also made by qualitative conjecture more than anything else. Some record is kept of the circumference of the stump, along its length, but since the circumference is around both hard and soft tissue, precise location is neither deemed necessary, nor is it practicable.

I'm persuaded that a cone-shaped "virtual socket" with a length-adjustable framework of some sort, yet to be devised, would serve as the "track" on which this thing would travel. I expect the design of the physical mechanism might be a bit tricky. That's TBD, as yet.

RE