Systrid is a CAD/CAM software package originally developed at the Helicopter Division of the French company Aerospatiale. It was brought into use at Aerospatiale in 1974. Systrid was developed to be used in the design and NC machining of the complex surfaces (or sculptured surfaces) that are so frequent in the helicopter industry. From 1977 onwards, the Battelle-Geneva Research Centres have marketed and further developed Systrid. It was recognised that the system could also be used in other industries with major requirements for complex surface handling. Today, Systrid is used by about a dozen European companies in the aerospace, automobile and turbine industries. From 1983 onwards, Systrid will be made available in the U.S. by the Battelle Columbus Laboratories. This article will concentrate on the automotive applications of the system. It is divided into three parts - a description of the system, how it is implemented, and examples of its use.