Bug Report: Curve.OffsetOnSurface

I’m facing what appears to be a bug in Rhino 7 for Curve.OffsetOnSurface. I recently upgraded from Rhino 6 to Rhino 7 and observe new behavior for offsetting of curves on a surface.

I’ve attached a script and screenshot of the behavior. I’ve tried to make the simplest possible script to recreate the behavior, which I first noticed on far more complex geometry. However, even simple geometry is behaving in unexpected ways.

The example shows a basic arc which I’m offsetting in a planar surface. The offset should be 1 at parameter 0 on the curve, 0.5 at 0.5, and 1 at 1. The result is a curve that is offset by unusual amounts to either side of the starting curve.

Please review my script and make sure I’m doing things properly. What I would expect is a curve that is offset by 1 at the ends and 0.5 in the middle, on one side of the starting curve (not crossing it).

BugReport_Curve-OffsetOnSurface.gh (16.0 KB)

Hi @gruedisueli,

Yes I see this - thanks for reporting.


– Dale

Thanks @dale for adding this ticket to your system! Do you have any idea about the timing of the release this might get wrapped into? Are we talking weeks, months?

Hi @gruedisueli,

Well the issue has been fixed. Whenever another Rhino 7 service release candidate is available, you can test - next week probably.

– Dale

Hi @dale is the service release candidate available? I’d love to give it a test.

Hi @gruedisueli,

The fix will appear in Rhino 7 SR29. I don’t believe we’ve released SR 28 yet.

If you want to test today, then download the current Rhino 8 WIP.

– Dale

RH-73651 is fixed in Rhino 7 Service Release 29 Release Candidate

I can confirm that in our own implementation which calls this function, this bug appears to be fixed.