Joining shapes together

Hello all, I am relatively new to Rhino and am struggling with joining two closed poly surfaces. I am trying to boolean the poly surfaces together but keep getting a failed to boolean error. After doing some forum research I tried exploding the poly surface and joining the outer edges together, which didn’t work. I have also tried adjusting the absolute tolerance under properties. I do have an overlap on all of the shapes and have no naked edges or manifold edges, I am not certain why I can’t boolean. Any help would be greatly appreciated. Thank you all!

Hi Kerri - please post a file with the two objects and someone will have a look.


Cathedral Square 3D v4.3dm (735.9 KB)

Hi Kerri - the best way here since you have coincident and near-coincident surfaces (makes it hard to get a clean curve of intersection even at more reasonable file tolerance) is to chop the bottom bit of the top object off at the tp plane of the bottom object and then work at the surface level with trimming and joining. BUT before you do anything please set the file tolerance to .001.

Hang on a bit and I’ll send a blow by blow… Cathedral Square 3D v4_PG.3dm (1.8 MB)

See also -


tolerance is reset, thank you for your help pascal!