Strange curve offset behaviour

Rhino Rhino for Windows
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1

I have a closed curve (the green one in my image) which gives me a strange result when I try to offset it to the inside: At one point on the curve it makes a wavy shape.
And what makes it more weird is that it only happens if I offset the curve between a distance of 0 to 19mm. After that I just get the offset result you would expect. Also, when I first offset the curve 50 mm to the inside and then that new curve 40 mm to the outside I don’t get the wave.

So, it’s not really a problem because I can fix it but I’m just curious to why this happened so I don’t have this problem in the future?

Anybody that has an idea?

Offset curve problem.3dm (70.0 KB)

2

I’m not sure why this is happening, something to do with your points maybe? If you run “SimplifyCrv” and then offset, the result is clean.

3

Got that, thanks.

http://mcneel.myjetbrains.com/youtrack/issue/RH-32787

-Pascal

4

@pascal
I’d try this in the WIP. I recall testing something that looked a lot like that a couple months ago.

5

strange but…
the squiggles don’t happen on mac.
?

6

Hmm interesting… Has anyone else on windows tried it?

7

FWIW, it does it in the WIP as well.

8

Just to give more information on how I got this curve: I extracted this curve from a polysurface using dupfaceborder which I then split up into pieces using curveboolean.
I do this often but it hasn’t occurred before.