Offset Approximation of Rational Trigonometric Bezier Curves

Offset curves are one of the crucial curves, but the presenceof square root function in the representation is main hindrance towardstheir applications in CAD/CAM. The presented technique is based on offsetapproximation using rational trigonometric B´ezier curves. The idea isto construct a new control polygon parallel to original one. The two endpoints of the offset control polygon have been taken as exact offset endpoints, while the middle control points and weights have been computedusing definition of parallel curves. As a result, offsets of rational and nonrationaltrigonometric B´ezier curves have been approximated by rationalcubic trigonometric B´ezier curve. An error between exact and approximatedoffset curves have also been computed to show the efficacy of themethod