I like that, grabbing the conic tangents from the referenced curves! Regarding segment, we're stuck to using the quarter segment of the slice through the cone.

One thread mentioned conics were used to define airfoil shapes in the early days of aerospace. I have not heard of that before. Our airfoil creator in AeroPack needs spines to match the empirical data typically associated with how airfoils are designed.

At Lockheed we used conics extensively to define fuselage cross sections. Conics are great because they are smooth (no inflections) and you can easily increase or decrease the shape via the rho value while maintaining the end tangents. We used this feature to rapidly optimize shapes for aerodynamics where changes in cross sectional area impacted drag.

The polyconic surface is the 3D extension of the 2D conic section to surface modeling. The polyconic surface was by far the most frequently used surface in the construction of the F-16, F-22, and other military aircraft projects at Lockheed.


Tim

Not exactly, but it should produce the desired results.

A polyconic surface is a procedural surface defined by a collection of law curves. The law curves define the 2D conic sections along with a spine. Types of law curves include rho, shoulder, slope control, edges, and surface edges.

The AeroPack manual describes them pretty well in Chapter 3 below.

http://www.darcorp.com/docman_uploads/AeroPack_Manual.pdf

Lockheed was not the first to use polyconics. First reference I can find was the P-51. A great reference on conics, polyconics, and aircraft design is Mathematics for Computer Graphics by Roy Liming.


Tim