'Periodica Polytechnica Budapest University of Technology and Economics'
Abstract
The rational splines have been included in the IGES (International Graphics Exchange
Specification) standard for about ten years, but they have been subjects of interest since
1967 [1]. The current kind of rational splines of our days are the NURBS (Non-Uniform
Rational B-splines), which are generalizations of B-splines and the rational Bezier curves
and surfaces at the same time. The popular scientific articles and the manuals (e.g. [2])
as well frequently mention as an advantage that these spline curves are accurate for conic
sections. For this reason, in this article we propose the rational representation of conic
sections as an introduction to the NURBS
