Catmull Rom Basis Definition

The Catmull-Rom basis definition is a modified form of cubic Hermite whereby adjacent control points in world space can be used as control point derivatives. This has the advantages that derivative control points don't need to be calculated, elements will definitely intersect their control points, adjacent elements using each other's control points as derivatives will maintain C1 continuity between them, and an object defined by multiple elements will be guaranteed to have C1 continuity throughout its xi space.