Strange curve offset behaviour

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)

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.

Got that, thanks.


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

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

Hmm interesting… Has anyone else on windows tried it?

FWIW, it does it in the WIP as well.

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.