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Part of Rhinoceros , Rhinoceros for OSX
Part Type Entity
Screenshot NURBS Curve.jpg

Non-Uniform Rational B-Splines, are mathematical representations of 3-D geometry that can accurately describe any shape from a simple 2-D line, circle, arc, or curve to the most complex 3-D organic free-form surface or solid.

See this overview of NURBS geometry for more information.

A NURBS curve is defined by four things: degree, control points, knots, and an evaluation rule.


A joined collection of NURBS Curves (and perhaps other kinds of curves) is a Polycurve


What is NURBS
A rundown of NURBS geometry by the makers of Rhino.