Sweep an in-plane profile along a spine polyline using rotation-minimizing
frames (no 180° flip at inflections). The profile is sampled in its own
(normal, binormal) plane at every station; opts.closed loops the spine and
skips the open-end caps. The result is a pseudo-SDF (exact distance only near
the swept wall), which contours cleanly. spine needs at least 2 finite points.
Sweep an in-plane
profilealong aspinepolyline using rotation-minimizing frames (no 180° flip at inflections). The profile is sampled in its own(normal, binormal)plane at every station;opts.closedloops the spine and skips the open-end caps. The result is a pseudo-SDF (exact distance only near the swept wall), which contours cleanly.spineneeds at least 2 finite points.