Constructs an interpolation cubic spline going through the fit points. The constructed spline has start and end derivative specified by the input data.

Public Sub New(
    fitPoints As Point2dCollection, 
    startDerivative As Vector2d, 
    endDerivative As Vector2d
)

public CubicSplineCurve2d(
    Point2dCollection fitPoints, 
    Vector2d startDerivative, 
    Vector2d endDerivative
);