Grasshopper offset bug?

[Yao]

Hi,

I just found a strange behavior when offsetting a polyline curve in Grasshopper. The offset result becomes wrong when the offset distance passes a certain point (see screenshots). However this issue does not exist when offsetting using Rhino command. Any clue why this is happening?

offset_bug.gh (4.0 KB)

Thanks,
Yao

[wim (Wim Dekeyser)]

Hi -

@Yao

I just found a strange behavior when offsetting a polyline curve in Grasshopper.

This seems fine in Rhino 8:

-wim

[Yao]

Hi Wim,

Thanks for the prompt response!

Yes, this works in Rhino 8. The error I had was in R7. I also tried in R6 and it wouldn’t even give me a result (see screenshot).

When I bake it to Rhino and offset it there everything is fine. It seems that the Curve.Offset() method in RhinoCommon API of Rhino 7 has the same issue. Just wondering if there are any workarounds to this problem in R7. And I am also curious why offset in Rhino works fine. Thank you!

Yao

[laurent_delrieu]

Welcome to the club.
The answer in R7 is Clipper !

We need to talk about Offset

Dear Rhino/Grasshopper developers thanks for Rhino 6, many useful improvements, render, Rhinocommon functions … but there is an old subject Polyline Offset see this thread : Are there some news about Polyline offset ? I know Clipper is a good solution for Grasshopper and Rhino. Update : @pascal it is not a Grasshopper question more a Rhino core function. There is a reliability problem with offset Polyline. It doesn’t work on some the cells which are simple polygon (see the picture). The sa…

[Yao]

Thank you, Laurent! This is awesome!