In June 1967 Steven A. Coons, professor of mechanical engineering and researcher in interactive computer graphics at MIT's Electronic Systems Laboratory, published Surfaces for Computer-aided Design of Space Forms, Project MAC Report MAC-TR-41, MIT.
Known as the "The Little Red Book,
" the paper described what became known as the "Coons Patch"— "a formulation that presented the notation, mathematical foundation, and intuitive interpretation of an idea that would ultimately become the foundation for surface descriptions that are commonly used today, such as b-spline surfaces, NURB surfaces, etc. His technique for describing a surface was to construct it out of collections of adjacent patches, which had continuity constraints that would allow surfaces to have curvature which was expected by the designer. Each patch was defined by four boundary curves, and a set of "blending functions" that defined how the interior was constructed out of interpolated values of the boundaries" (Carlson, A Critical History of Computer Graphics and Animation, accessed 05-30-2009).