Can someone please tell me how do i change tihs stations open curve to closed polylines,thxnamjesteni.dxf (441.8 KB)
Do you mean polycurves, as you are starting from curves? (Polycurves are smooth, polylines are a series of straight segments).
If so, for each station, join the two curves. Then select all the curves and use _CloseCrv command (also available on the curve edit tools menu). You can, of course, close the curves individually but it is quicker to do them in one hit.
If you do want polylines, then do as above but add in a _Convert step with the lines option (curve convert menu) after the joins - again you can select all the curves and convert them at once.