When one has a curve that you'd like to make into a surface, network or sweep work great. Are there some tricks I'm missing to add a rail that follows the profile for sweep or in the case of network, to add a line so that MoI can read it as two different sets?

As a simple example:



I can draw a line(s) in the middle, but is there a way I'm missing to have MoI "do it for me"?