When is the Set Flow Direction command enabled?
The Set Flow Direction command is enabled whenever the current geometric network has sources and sinks and when you are in an edit session. You need to set the flow direction in a network after you create it, and again any time you change the topology of the network. You can change the topology of the network by adding and deleting features, connecting and disconnecting features, enabling and disabling features, or by changing the AncillaryRole attribute of a feature.
