First of all my expression of great admiration of what you have accomplished in such a short time.
In shoelast-design, some control points are related to other control points or related to input variables by use of formulas.
Other control points are "free-floating".
In fact, to formulate correctly: some components (i.e. x, y or z) of control points are free-floating, while other components are subject to conditions.
For "free-floating" components of control points, my suggestion would be to be able to alter the position of control points by dragging them onscreen.
I don't know whether this is possible later on, or it is crucial information for the program set-up.