I'm not sure that thinking of this as a "3D path" is helpful. As I understand it, the mandrel that the filament winds onto rotates at a constant rate, so all you need to do is move the head that dispenses the filament back and forth horizontally, twisting it a little at each end.. You would do that by writing a simple Gcode program that specifies the speed of movement and the limits of travel.for that axis (call it "X"). The twisting move at the ends of travel would be done by Y, set up as a rotary axis denominated in degrees. So the code would look like this:
G01 X20 (assuming the mandrel is 20 inches long) F30 (move the head at 30 ipm)
Y45 (assuming it needs to rotate 45 degrees)
X0
Y0
X20
Y45
X0
Y0
etc.unitl the reel is full, which might trigger a sensor that stops motion