Xtreme Network Curve & Flow on Surface

 From:  Ced (FRACTIONALIST)
8288.1 
Hey Guys,
I'm interested in using FLOW ON SURFACE.
I'm using NETWORK CURVE (Network in Moi) to build a surface.
1. I'm having trouble building a rectangular object enclosed on ALL SIDES with a WINDOW OPENING on one side.
2. I can build the object FRONT and then build the object BACK, however when I go to FLOW ON SURFACE - it won't let me choose BOTH SURFACES!

Is there a way to COMBINE two surfaces make with NETWORK CURVE so that when you FLOW ON SURFACE you can SELECT BOTH - or they register as ONE SURFACE?

I tried JOIN - and they appear 'joined' unless you wish to FLOW ON SURFACE, then again, they register as 2-separate surface!

Q. If you build two NETWORK CURVE surfaces - is it possible to combine them to make them ONE SURFACE?

I understand you need a closed curve at each end - with open curves between the two, however, if I make a 'topography' of curves - the result goes crazy abstract.

I'm trying to make a 'closed' rectangular shape - that I can flow a pattern onto front and back - that has a 'window' (opening) in the front only.

I really like NETWORK CURVE and am hoping to understand it better - and make it my preferred surface making tool.

Are there any advanced radical clips on how to learn to make an extreme (cool) Network Curve Surface?

Any suggestions?
Cheers,
Horace