I once had a MEL script I got from HIghend3D that allowed you draw a curve with another CV. That CV could be a curve endpoint on a surface, for instance. For example, you could make a NURBS sphere and attach a curve to it, animate the sphere with surface curve rotating and moving etc, and then apply the MEL and the result would create a new curve that perfectly intersects that CV in space. Useful for drawing spirals or curve-paths for fighting jets, or what not.
Does anyone recall the name of this nifty MEL? Or another tool that can create similar results? I used to have it a long time ago and could use it again.