private static Point3dCollection GetNonRectClipBoundary( Polyline2d polyline, Transaction tran) { Point3dCollection points = new Point3dCollection(); foreach (ObjectId vxId in polyline) { Vertex2d vx = (Vertex2d)tran.GetObject(vxId, OpenMode.ForRead); points.Add(polyline.VertexPosition(vx)); } return(points); }