Quadratic trigonometric polynomial curves with a shape parameter

Quadratic trigonometric polynomial curves with a shape parameter are presented in this paper. Analogous to the quadratic B-spline curves, the trigonometric polynomial curves are constructed with three consecutive control points for each curve segment and are C-1 continuous with a non-uniform knot vector. With the shape parameters, the trigonometric polynomial curves can yield tight envelopes for the quadratic B-spline curves and can be closer to the given control polygon than the quadratic B-spline curves. The trigonometric polynomial curves also can be decreased to linear trigonometric polynomial curves which can represent ellipses. (C) 2002 Elsevier Science B.V. All rights reserved.