A simple technique for NURBS shape modification

Non-uniform rational B-splines (NURBS) have become a de-facto industry standard primarily because they offer a unified mathematical form for representing both freeform shapes and analytical curves or surfaces. Despite these advantages, designers need software that lets them work with NURBS in a natural way. The paper presents a unified approach to NURBS shape modification that builds on a perspective functional transformation of arbitrary origin and provides a homogeneous interface based on simple, easily understood geometric concepts.