- GetSpline(<V0>, <A0>,..., <An>, <Vn> )
- Description: returns the list of the control points corresponding to the cubic spline passing through the points <A0> to <An>. <V0> and <Vn> are the speed vectors at the ends [constraints], if one of them is zero then the corresponding end is considered as free (without constraint). The result has to be drawn with the graphic command Bezier.