Solid Union problem in combining closed brep pipes

Hello together,

I want to join closed breps each other and then shell them in order to get a multipipe. Hovewer, solid union component doesn’t work. Do you have any idea, why it doesn’t work?

Note: I tried also with multipipe component. It didn’t work too.
Solid union (6.7 KB)

Just a guess at what you want - exhaust manifold? (11.5 KB)

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Hi Birk,

actually, I don’t want to have a exhaust manifold. I need it for cooling. But, your solution is unfortunately not, what I need. I want to combine these closed breps and then, I will open hole with 1 mm thickness. However, I have a trouble with solid union :frowning:


Yup- I’m not surprised my solution is not what you wanted - it just looked sort of like an exhaust manifold to me so I went down that path.

If you Cap the shape I came up with you’ll get 6 closed Breps. Maybe then you can make some curvy pipes to SDiff from that to get the holes you want. I don’t think GH will produce a single closed BRep for the entire assembly - I’ve encountered situations like this before and just gave up trying to resolve them. It might be that someone who knows more about Rhino could do it with Rhino commands or internal functions.

let’s say that Rhino diamond tip is not relative to boolean operations :slight_smile: -at least from my personal point of view-

general tips for a succesful boolean operation are (at this point in time) to not have multiple shared coplanar faces and to not have seam lines intersecting -slaloming on/off intersection- with other solids involved in the same boolean operation

I have tried a different approach that was using just your rail curves → offset +/- 4mm → close each snake head and tail in a planar curve → extrude +9mm along Z → region union all together

extrude 9mm +Z direction → cap holes

at this point manually picking the index of the edges (I want to die)

until noticing this nice serie of additional edge-things happening here and there: closing Rhino and GH in a click, no non-working definition attached, sorry

very sad story indeed :frowning:


hi inno,

i was really excited, while I was reading your text. I thought, you got the solution. :sweat_smile:

But, thank you anyway for your effort :slight_smile:
I baked the geometry and unite with Siemens NX. Hopefully, I can find a solution in grasshopper in order to automate my design process.

Really sad that so great software like Rhino has serious problems with boolean operations. Hopefully, it will be fixed in the next upgrades.