Hi Burr, here is a more illustrated example.

In the situation that Renato described, he had 3 curves, one closed one at the bottom and then 2 open ones. here they are shown separately for clarification:



All together these 3 look like this:




In order for Network to work properly, it needs to be able to detect a 2D grid layout to the curves. The 2D that I am referring to here really is the exact same kind of thing as the latitude (horizontal) and longitude (vertical) lines on a flat map which correspond to curved lines on a globe of the world.

The arrangement as currently shown is not possible to "unwrap" to a flat plane like a map. For example if you try to take the lower closed curve as a line around the equator, then that would mean that the other curves should be longitude lines that go up and have a common end at the "north pole" of the globe. But they don't end there, they keep on going past that area and end on the equator again.

In a 2D map of the world there is no such thing as a line of longitude that touches the equator twice, each line of longitude can only touch the equator once on a flat map of the world.

So the current arrangement is not suitable for unwrapping, it means it is also not suitable for Network.

To get a suitable arrangement, these curves must be diced apart. There are a couple of different ways to do it.

One way is to leave that bottom "equator" closed curve alone, and then cut the other 2 curves with each other (to do this, select them both, then run Edit/Trim, push "Done" or right-click at the select cutting objects prompt since you want them to cut each other, and then push "Done" or right-click again to keep all the pieces since you don't want to throw away any in this case).

This makes them into 4 pieces and now they are like pieces of longitude lines since they will end at the "north pole", here I have shown this arrangement slightly separated for clarity and with a red dot at the new "pole":



There are other ways you can do it too - you can instead leave those 2 upper curves alone and instead slice up that lower closed curve into 2 pieces, like this:



That creates 2 pole areas, it is like a globe lying on its side now. It doesn't matter which way the globe is oriented, as long as all the curves involved in the network can be organized into a 2D latitude/longitude set then they can be used for Network.

Hope this help explain the arrangement better!

- Michael