B-Spline Curves

B-spline curves follow the general shape of a control polygon, the vertices of which are known as control points. These control points act like magnets which pull the curve towards them. With a little practice, you will find this a very natural way of controlling the shape of a curve. To interactively create a B-spline curve, set the input mode to B-spline, and use the command CURVEÞ Design:Input to enter the control polygon.

To move, add, or delete control points, enter the command CURVEÞDesign:Edit. You could also produce sharp angles, straight-line segments and circular arcs etc. In other words, practically any curve shape may be defined using the available curve editing functions.

It is good to know the following facts about the B-spline curve properties: