Hi Billabong, you generally want to make things more by intersecting parts that push through each other rather than going around and filling in patches like this.

If you do want to fill in using Network, it will be tough to do it on edges that are meeting up a little loosely like you have here.

That's because to Join the new patch needs to have its edges match up close enough to the original edges, when you edit the curves that's basically moving stuff away from where Join will want it at. But just using Network without moving pieces isn't going to help because the surface that network generates will be an average anyway where things don't touch exactly.

Another complicating factor is a couple of micro edges in this area:





If you turn on surface control points on your Network, you'll see that even though the shape is very nearly planar, it's got a bunch of control points all sliding and skewing along like this:



This is not that great because you generally want surface control points to naturally follow the surface shaping and boundary details come from trim boundaries instead of baked directly into the surface structure.

I'll take a look at doing some repair work to simplify the edges.

- Michael