Hi Brian, really a "control point curve" and a "through points curve" are just different construction methods both of which just create a NURBS curve...

Do you mean you want to build a new curve that is interpolated through the control points of an existing curve? There is nothing prepackaged up for that right now and it will be difficult to script it because the control points are not currently exposed to script. You can turn on control points and snap on to them while drawing a "through points" curve though.

Could you maybe describe a bit more about what you're trying to do?

- Michael