Offset Curve Failed

I have a set of planar surfaces that I’m turning into boundry curves to offset. The offset curve component fails, “1. Offset plane must be provided if the curve is not planar itself”. I have used components to confirm the original surface is planar, confirmed the resultant boundary curve is planar and closed.

Is this a bug or somethings else?

i think you’re passing the wrong data type - as in, you’re not passing a curve

uploading your gh file with internalized data would help
as well as sketching the desired result

Not the wrong data type. There is a conversion from planar surface to curve using a curve components.

Here is a gh definition

dome offset probelms.gh (35.6 KB)

i see what’s wrong. the curves are not planar, so you need to pass a plane to the “P” input of the offset. if you click on the error ballon you sometimes get explanations about why a certain component failed

1. Offset plane must be provided if the curve is not planar itself

if you pass for example an XY plane to P, it will offset the curves horizontally, which should make the offset component work, but i’m almost certain that’s not your desired result…

if you could explain what you want the offset to do, maybe there’s a way to achieve that somehow

You have now reach the point I was at when first posting, including the exact same error code text I quoted.

Based on how these curves are made, they should be planar. They are the bounding edges of planar surfaces. I tested the surfaces to confirm they were planar (they are). I checked that the generated curves were planar as well (they are).

So if by definition of how they are made they should be planar and by every method checkable grasshopper understands them as planar, what is going on and why am I being told these are not planar curves by the offset curve component?

To repeat my original question, is this a bug or something else?

well, there must a be a bug somewhere,
anyway, this works

the simplify curve is optional but it cleans up the curve (from a generic curve to a proper polyline)

I don’t have sasquatch installed so I replaced the Brep Offset with the Pufferfish one

despite that, the direction of a curve somehow matters when you offset it… just to solve the problem to the root, if you offset each curve in both directions and pick the shorter one, it will always be the inside one:

dome offset probelms_Re.gh (42.5 KB)