Function make_apex_band 

pub fn make_apex_band(
    model: &mut Model,
    surface: &SurfaceGeometry,
    ring: &Shape,
    tol: Tolerances,
) -> OgeomResult<Shape>

Build the face of a revolution cap: one closed ring belting a cone, with the apex the file never wrote synthesised as the degenerate ring the band needs.

A cone face bounded by a single circle has exactly one other boundary the geometry permits, the apex, because the region away from the apex is unbounded. The apex becomes a vertex and a degenerate edge, and the rest is make_revolution_band, one authority for the seam either way.

Errors

OgeomError::Construction if the surface is not a cone, or the ring resists the band construction.