Why can't I Boolean union these polysurfaces?

Hi,

Could somebody tell me why I can’t Boolean union these polysurfaces, and also what I should do to manage doing it?
Boolean union fail.3dm (640.6 KB)

Thanks a lot

Seb

Hi
These two groups Union just fine:

If you Intersect the two groups and inspect the curves at the bottom, you’ll see they are open, incomplete curves. This is why the Union is failing.
You’ll probably have to manually tune up the curves so they are closed, Split the surfraces with them, delete the unneeded bits, and Join the result into a single closed, solid, polysurface

This process is described in detail in this FAQ:
http://wiki.mcneel.com/rhino/booleanfaq

Good luck

1 Like

Thank you for the reply,

I’ll have to study that FAQ, it’s beyond my level but I need to learn this split and join business
I managed by restarting with the 1st curve and aligning the 1st and last points with SetPt.

Thanks a lot
SG