Hi Hbasm, the problem is with your 2 curves that cross each other and then come back to touch the same base curve - that prevents MoI from properly unwrapping your curves into a flat 2D grid.

Basically, for network to work your curves must be arranged like latitude or longitude lines on a globe.

In your example you have one closed curve - that will make that curve behave like the equator line in a globe.

Now once you have an equator, you cannot have lines of longitude that start at the equator then go up over the north pole and then come back down and touch the equator again - longitude lines should end at the pole and not continue up past the pole and wrap back down the other side of the "globe".

It's a bit difficult to explain but please refer to this previous post that has some illustrations which will help to explain it better:
http://moi3d.com/forum/index.php?webtag=MOI&msg=1778.6


The basic solution is to cut your 2 open curves with each other so that they can be unwrapped to a 2D grid.

Actually your curves are already made up of segments that should work for this, so instead of cutting them you can use Edit/Separate on them. To make your curves work, you will need to select the 2 open curves, then run Edit/Separate, then re-join the pieces together to form 4 curves in this kind of an arrangement (shown separated slightly here for illustration):



With your curves arranged in this manner, MoI will be able to figure out how to unwrap them into a 2D grid layout and then can construct the Network:



- Michael