void HSpline::ToBiarcs(const Handle_Geom_BSplineCurve s, std::list<HeeksObj*> &new_spans, double tolerance)
{
    new_spans_for_CreateArcs = &new_spans;
    if(tolerance < 0.000000000000001)tolerance = 0.000000000000001;
    tolerance_for_CreateArcs = tolerance;
    gp_Pnt p_start;
    gp_Vec v_start;
    gp_Pnt p_end;
    gp_Vec v_end;
    s->D1(s->FirstParameter(), p_start, v_start);
    spline_for_CreateArcs = s;
    CreateArcs(p_start, v_start, s->FirstParameter(), s->LastParameter(), p_end, v_end);
}