public List <sLine> TosLines(Curve c, double maxLenTol)
        {
            List <sLine>  lns = new List <sLine>();
            PolylineCurve pc  = c.ToPolyline(0, 0, 0.0, 0.0, 0.0, 0.0, 0.0, maxLenTol, true);

            Curve [] segs = pc.DuplicateSegments();
            for (int i = 0; i < segs.Length; ++i)
            {
                lns.Add(TosLine(new Line(segs[i].PointAtStart, segs[i].PointAtEnd)));
            }
            return(lns);
        }