空间等距线的非均匀B样条形式

本文给出了用非均匀Ｂ样条曲线表示空间曲线的等距线的方法，并且通过修正曲率和挠率，获得先顺的等距线

Non-Uniform B-Spline for Offset Curve of Space Curve

To the authors' best knowledge, only Pham in 1992 4] spoke of offset curve of space curve, but did not provide any algorithm. The authors now present an effective algorithm for obtaining such offset curve.The authors' algorithm include s offset curve of plane curve as a special case. It overcomes two shortcomings in existing algorithms for offset curve of plane curve: (1) How to get faired approximation of offset curve is not satisfactorily considered in existing algorithms. The authors' success in obtaining faired offest curve is achieved essentially through successive correction of curvature and torsion. (2) Pham's taking the errors of midpoints of segments of curve to examine perfection of result 3] sometimes runs into difficulty. Pham's algorithm uses uniform cubic B-spline curves, while the authors' algorithm uses non-uniform B-spline curve.