On Tue, 24 Nov 2015 16:45:02 -0600, Behdad Esfahbod wrote: > When you De Casteljau the curve, the new line spline has slightly > different tangent at every point of the curve, and hence different > normal vector. You mean in terms of the parametrized form of the curve? Because I thought geometrically speaking, de Casteljau decomposition is exact.