Offset curve problem

I have an offset curve problem with this closed curved (which analyze-check tells me is valid) – when I try to offset it in the original (large and complex) file, I either get just a part of the curve or Rhino crashes.
When I copy it to a new file with nothing else in it, I get three curves which extend each other so I can’t join them.

My mistake somehow or a bug?
Thanks in advance - Jan

Offset-curve-problem.3dm (2.5 MB)

Next to the end of the black curve, the red curve has three points within 0.003 mm

I think you could delete two of the three points


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There are actually 6, same three on the other side…


Hi Jan - in this case, run SimplifyCrv on the polyine then offset.



Great, thanks for your replies! Worked!
But to Martin and Helvetosaur: how did you find that? Is there a command to find those problems? Cause as I wrote: check told me, the curve was okay.

No, no command, just simple deductive reasoning… Find the spot where the offset curve is bad - in this case the ends of the two curves that you can’t join because they overlap a bit - and then examine the original curve near that spot. Turn on control points and zoom in, then you see the extra segments.

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Okay, great, thanks a lot!