Networksrf "Unable to use curve network"

When I get the error “unable to use curve network,” I usually just keep trying different curves until I find one that works, but I really like this curve network. What is usually the reason for getting this error? Just trying to figure out how to best use this command.

Hi Christine - the network must be able to be resolved into a rectangular grid, i.e. in exactly two directions - so, curves cannot be strung together end to end as separate curves, curves cannot cross one another more than once, curves going in one direction cannot cross curves going in the same direction.


Thanks for that image! What’s the difference between the curve network on the top left and bottom left?

Hi Christine - the green and cyan curves are separate curves, end to end - that does not work. I guess I could have used more contrasting colors there…


Oh, thanks. That makes sense, but I still can’t figure out why I can’t use this curve network?

NetworkSrf requires:
ALL the curves in one direction must cross ALL of the curves in the other direction
None of the curves in each direction can cross any of the curves in the same direction

The above will only be true if the curve on the left edge is actually two curves with the split between the curves near the red line I added to the illustration. However if that is true the resulting surface is likely to be less than good. A better strategy for that shape may be to create two surfaces rather than one. Post the curves and you design intent and someone may provide a suggestion as to how to proceed.

Hi Christine - I’d reinforce David’s comment - you should think about making this some other way - it is asking a lot of NetworkSrf to make what you want here, I would say, let a lone making it well. Can you post the curves?


i am a beginner in this. i was reading threads related to this just to boost my knowledge .
thanks all for posting your replies. your replies were helpful for me.
best regards!!

I am trying to create a 3d potty in Rhino but keep gettin the “unable to sort curves. Select curves one at a time” when I want to NetworkSrf.
What am I doing wrong here? can someone please help ?

Hi @diana.guney93
In order to provide some proper help, it would help if you upload the curves you have. In general: A complex shape like that usually needs to be made up from several surfaces; some could be networksrf’s, some could be blends, revovles, sweeps, lofts etc. - it really depends on the shape. To get a better understanding on how to construct and correctly “sort” your curves when using Networksrf, take a look at the videos in the help file. Start networksrf and press f1 or look at the Help tab in the panels to the right.
HTH, Jakob