public bool Load(StreamReader sr)
 {
     try
     {
         int numplys = int.Parse(sr.ReadLine());
         for (int c = 0; c < numplys; c++)
         {
             PolyLine3d pl = new PolyLine3d();
             pl.Load(sr);
             m_segments.Add(pl);
         }
         return true;
     }
     catch (Exception )
     {
         return false;
     }
 }