Module fillet_variable 

Variable-radius (tapered) fillet blends (ADR 0051).

Why this is not a cone

A constant-radius fillet on a vertical edge sweeps a cylinder. Tapering the radius linearly with height does NOT give a right circular cone: the blend centre moves along the bisector as the radius grows, so the axis and the rulings disagree. The surface is a cone in the projective sense – every ruling passes through one apex – but an OBLIQUE one, and Surface::Cone is right-circular only. Measured obliqueness is far above numerical noise at every interior angle and taper tested (ADR 0051).

Each horizontal section is still an exact circular arc, so the surface is a linear loft between two rational quadratic arcs. That is representable exactly as a rational B-spline, and that is what this module builds.

Structs

TaperedFillet

A fillet whose radius changes linearly along the extrusion.

Functions

tapered_blend_surface

The tapered blend surface: a linear loft between two rational arcs.