Function make_band_between 

pub fn make_band_between(
    model: &mut Model,
    surface: &SurfaceGeometry,
    rings: [(&Shape, PlanarCurve); 2],
    tol: Tolerances,
) -> OgeomResult<Shape>

Build the face of a band between two closed rings that need not be circles, each with a caller-supplied chart image.

make_revolution_band’s general sibling: where the band derives each circle’s row and pcurve itself, this takes the rings as they come (a fitted tangency curve, a wavy trim), with the pcurve the caller already knows for each, same-parameter over the edge’s own range. The seam stays an exact iso-column of the surface, which is what routes around the closed-form refusal in make_face_with_pcurves.

The caller’s contract: both rings are closed, both chart images run the full period forward in u, and both start on the same column; the seam runs there, between the two start vertices. One ring may be a pole: a degenerate edge whose image is the pole’s row over (0, period).

Errors

OgeomError::Construction if a ring is not closed, the images disagree about the start column or do not run the period forward, or the surface’s iso-curve has no closed form.