pub fn tapered_blend_surface(
bottom: &BlendCorner,
top: &BlendCorner,
height: f64,
) -> Result<BSplineSurface, GeomError>Expand description
The tapered blend surface: a linear loft between two rational arcs.
u runs along the arc (degree 2, rational), v along the extrusion
(degree 1, exact for a linear taper). Both bounding arcs are exact
circles, so every horizontal section of the loft is an exact circle too.