Hi Patrick, I'm not able to repeat the additional edge you got with Network. It could help for me to see what went wrong for you if I could get a file with only the curves in it that you used to make the Network.
Here's what I did with your posted file:
Selected these edges and used Edit > Join to glue them together into 2 independent curves:
Selected these edges and used Edit > Join again to make a single joined curve:
Selected this one edge and used Copy/paste (Ctrl+C/Ctrl+V) to duplicate it as a regular curve.
Selected these 2 curves and used Edit > Extend to make them come to a sharp point:
Selected these 2 curves and used Edit > Extend to make them also come to a sharp point:
Then these 4 curves can be selected:
And running Construct > Network gave me this:
It's not really necessary to do a separate Rebuild before doing Network (unless you need to use one of the other rebuild modes than "Refit" mode) , because Network itself already incorporates a rebuild in it anyway.
Now for doing the knurling it's pretty difficult to model knurling directly and I'd think you may need to make it further extended or else the knurling is going to follow these lines of the surface which will make them in curved lines:
Those are isocurves that I extracted from the surface.
You may need to build something that's extended more like this to avoid distortion:
Knurling like you show there is such a small sized feature I'm not sure you can get a good 3D print of it with the stepping resolution in a normal 3D printer.
Texture mapping may still be a better way to go, if you use a displacement texture map in a rendering program you can probably have it output triangulated mesh geometry which can then go to STL format. 3D-Coat and ZBrush may be good at applying this kind of displacement bumping too.
- Michael
