Editing Non-uniform rational B-spline (section)

=== Curvature ===
The most important property in [[differential geometry]] is the [[curvature]] <math>\kappa</math>. It describes the local properties (edges, corners, etc.) and relations between the first and second derivative, and thus, the precise curve shape. Having determined the derivatives it is easy to compute <math>\kappa=\frac{|r'(t) \times r''(t)|}{|r'(t)|^3}</math> or approximated as the arclength from the second derivative <math>\kappa=|r''(s_o)|</math>. The direct computation of the curvature <math>\kappa</math> with these equations is the big advantage of parameterized curves against their polygonal representations.