Preventing curve from closing when end points are coincident?

I am trying to make a surface from curve network and one of the edges having coincident end points but rhino keeps closing the curve and then curve network won’t accept it.

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Or maybe I’m not understanding the question

Daniel that still builds a closed curve.

I agree that with new curve construction, if you put the end points on top of each other it seems likely you want the resulting curve to be closed. This seems like the expected behaviour.

However when I drag drag one end point onto the other I expect the points to stay as end points, not magically merge forming a closed curve that nobody asked for.

For example when you drag an end point of two separate curves together, they don’t automatically join and form a single curve. You just get two points at the same coordinates like you would expect.

Yes, sorry - I should have read your post properly. I think I understand the issue now.
It seems to be the same as discussed here:


One way is to move the ends apart a tiny distance (and move them back together after making the surface). Depending on your geometry there might be a better way though.

Yup exactly.

I’m just being a squeaky wheel.

You should have to run something like MergePoints to trigger this behavior… or CloseCrv and remove the unwanted point.

Is it possible that Rhino’s only conception of curved closed status is if the end points are coincident? I.e. curves don’t carry some kind of flag that says they want to be open or something.

I guess it would be easier with the file. maybe networksrf is not the answer