Understanding Surfaces: What's the difference?

I have two simple 4-sided surfaces in my model:

When I look at the UV, they appear to be the same, and the normals appear the same as well

but when I select them, their gumballs are opposite:

and then later, when I try and do things with them in Grasshopper that depend on the ‘top’ edge, I get different results for them.

How can I see / make them both the ‘same’ (vague word I know. . . ) ? What else can I control other than the UV? Is there some other orientation parameter someplace that controls them someplace?

thanks for any guidance or insight,

surfaces.3dm (3.3 MB)

Your two surfaces here appears to have the “same structure”, everything is sorted the same way.

Maybe try to reset the gumballs?

please attach that .gh file . Any test I tried gave me coherent results in your surfaces. Same order of control points or edges.

Hi Ed - Gumball, set to align to object, shows the same on both surfaces, here. What setting is on the gumball in your test?



Ah! I did know there were different options for the gumball? I had mine set to ‘Align to CPlane’ (apparently).

If I switch to ‘Align to Object’ then yes, they show up the same in that case.

That makes sense now - thanks!

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Hi Ed - I guess I’d expect them to be the same when set per CPlane as well, unless they had been moved like with GumbalRelocate or somerthing.