METHOD FOR GENERATING TWO DIMENSIONAL AND THREE DIMENSIONAL SMOOTH CURVES AND FOR DRIVING CURVES FORMING DEVICES

A method for generating curves and an associated method for operating a curve forming device are disclosed. According to a preferred implementation, the curve is formed as a piecewise series of arc segments (14' and 16'). The shapes of the segments (14' and 16') are derived by defining a control polygon (P.sub.0, P.sub.12, P.sub.3), defining an outbound polygon (P.sub.0, P.sub.1 ', P.sub.2 ', P.sub.3) relative to the control polygon, and determining centers of curvature (18' and 20') and radii for the segments (14' and 16') relative to the outbound polygon. The resulting curve can be two or three dimensional and can be expressed in conventional numerical control languages for implementation by curve forming devices.