Constrained curve drawing using trigonometric splines having shape parameters

The problem of drawing a smooth obstacle avoiding curve has attracted the attention of many people working in the area of CAD/CAM and its applications. In the present paper we propose a method of constrained curve drawing using certain C1C1-quadratic trigonometric splines having shape parameters, which have been recently introduced in [Han X. Quadratic trigonometric polynomial curves with a shape parameter. Computer Aided Geometric Design 2002;19:503–12]. Besides this, we have also presented a simpler approach for studying the approximation properties of the trigonometric spline curves.