What causes region union to mess up like this?

[Kyuubimode]

Hi, what exactly is causing region union to mess up here? How do I avoid this?

region union mess up.gh (6.3 KB)

[Gijs (Gijs de Zwart)]

hi @Kyuubimode
this seems a Rhino 8 bug, thanks for reporting

RH-85158 CurveBoolean wrong result

[Kyuubimode]

Ah okay. Hope this gets resolved soon, kind of dependent on region union for a lot of things happening in a big grasshopper project.

[nathanletwory (Nathan 'jesterKing' Letwory)]

FWIW if you explode and rejoin the top-left rectangle the region union will work. Didn’t check what exactly could be wrong with that rectangle, but here an explode and join (of all rects, but just top-left should be enough)