If you use FEFLOW 6.1 you need a selection of type [b]Slice Edges[/b], [b]Join Edges[/b], [b]Slice Faces[/b] or [b]Join Faces[/b]. You may access these types in the [b]Selection toolbar[/b]. After you selected the Edges or the Faces you need to go to the [b]Data panel[/b]. Right-click on [b]Discrete Features[/b] and choose the flow law of interest.