# Nonuniform B-splines

We have seen, that uniform B-splines are used to build closed curves. You need
an open uniform knot vector, if you wish your B-spline to start and end at
your first and last control points. You see below (n=3 k=4) B-spline with the
*[0 0 0 0 1 1 1 1]* knot vector (really *[.0 .001 .002
.003 1 1.001 1.002 1.003]* are used as I was lazy to make an accurate
applet :)

An order *k* open uniform B-spline with *n + 1 = k* control
points is the Bezier curve of order *k* (you see cubic Bezier spline
in the right applet).

At last you can compare quadratic, cubic B-splines and Bezier curve
of degree *n = 7*

You can play with control points and knots to see how they influence on
the curves shapes (e.g. multiple control points and knots).

Contents
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*updated* 8 August 2001