ARC-NORMAL VECTOR APPROXIMATION OF OFFSET CURVES OF PLANE NURBS CURVES

On the basis of the one- to-one correspondence of the characteristic points of the offset curve from a given generator curve with those of the generator, this paper presents the arc-normal vector approximation of offset curves of plane NURBS curves. This method has the following advantages: (1) The offset curve and its generator have a united NURBS representation; (2) Its computation is simple,geometric property is apparant and approximating precision is high.