A geometrical approach to curvature continuous joints of rational curves

Abstract Rational Bezier curves are discussed from a projective-geometrical point of view. A projectively invariant Bezier representation of rational curves is presented. Geometric continuity of second and third order is characterized by special projective maps. These maps (certain perspective collineations) preserve curvature properties of a curve at a point. As an application, constructions for geometrically continuous joints of rational curves are derived.