The script offers a way of rapidly creating extruded/lofted tubular geometry with precisely controllable width at every cross-section using only two slightly offset curves of identical CV-counts.
The primary curve is used to define the path of the extrusion, and the control (secondary) curve outlines the hull of the extrusion along the primary curve.
In other words, at any given CV the width/thickness of the resulting extruded geometry cross-section is going to be determined by the distance between the CV of the primary curve and the corresponding CV of the control curve.
Highly useful for modeling organic tubular shapes (e.g. roots, vines, tentacles...)
V1.11 update: fixed some minor issues with selecting section curves and hull-geometry.