Join Fail.3dm (47.9 KB)
Can anyone work out why these curves join to give an open curve rather than a closed curve?
It joins into a closed curve here in Rhino 8 BETA.
Thanks Martin, that is encouraging I’m running Rhino 7SR35 - anyone know what is going on there? does it fail in other Rhino 7’s?
This is an odd one. If you select all and join, it makes a bad object. However if you select some different subsets of the curves and join in several steps it sometimes makes a good closed object, and sometimes not. If you take the first bad object and explode and rejoin, it becomes a good, closed curve. There is some sort of weird tolerance thing going on.
Yes, V8 seems to have fixed that particular problem.
there is a small curve here
that is probably causing the issues. If you join that first to its neighbors, then join there rest to it, you get a closed curve.
I suspect this has been fixed in V8 by a tune-up that @chuck made to an issue found in CurveBoolean
Good catch, I did a SelShortCrv with the 0.01 file tolerance and didn’t find anything… because that curve is 0.015 long. Though not necessarily good practice, in theory, that should still be acceptable.
Thank you @Gijs & @Helvetosaur It is good to understand what is going on here 
Is there any likelyhood of the tune up reach Rhino 7?
This geometry comes from one of our CNC customers (not sure how they generated it).
not very likely, no