Today I read a paper titled “Analytic Definition of Curves and Surfaces by Parabolic Blending”
The abstract is:
A procedure for interpolating between specified points of a curve or surface is described.
The method guarantees slope continuity at all junctions.
A surface panel divided into p x q contiguous patches is completely specified by the coordinates of (p+1) x (q+1) points.
Each individual patch, however, depends parametrically on the coordinates of 16 points, allowing shape flexibility and global conformity.