Curves, loops, and knot vectors

Curves and loops are based on NonUniform Rational BSplines (NURBs). NURBs are a generalization of Bézier curves that allow an arbitrary number of points, exact representation of conic sections, full control over continuity, and arbitrary order. This section contains the background material you need to get you started using the functions and constructors for curves and loops. However, you may want to increase your knowledge further by obtaining and reading some of the books listed in the Preface to this manual.

NURBs are based on control points, the order of the curve, and a knot vector. Control points guide the shape of the geometry by specifying the location of the points of the curve. The curve's order determines the minimum number of control points that define the curve. A knot vector is a sequence of parameter values for determining the continuity along a curve's length. A knot is the location where two curve segments join and form a spline. It is represented by a parameter value.

NOTE Refer to the end of this section for code examples and screen shots that show curves and loops created with different curve order, knot vector, and control point values.


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