Grasshopper Solid Union - Uniting two closed BReps

Hi @chris and all,

I am writing due to an issue I am facing since a week, about uniting two closed BReps. So, I have a number of closed Breps (rectangle - building footprints) and the same number of closed Breps (triangle - roofs). I am trying to make these two closed BReps into one. I am following the tutorials in YouTube for energy simulations and I would like the final closed Brep to convert it to dragonfly object.
However, when I am trying to unite these two Breps I get this error: β€œ1. Boolean Union set is empty.” (see img below)
Do you have any idea about that issue?

Thanking you very much in advance.

Kind regards,

Hi @Nasia_Apostolopoulou,

As your question is purely geometry related you would probably be better placed to post it on the Rhino / Grasshopper discourse forum.

In my experience the solid operations are some of the most temperamental in Rhino. One thing I do if I hit this issue is to bake them and see what boolean Union in Rhino returns to try and narrow down the issue.

I also have a feeling that if you pass two closed breps that aren’t touching to solid Union it will return that error and no geometry in the output - so script resilience wise it might be a faff to handle.



Hi @charlie.brooker many thanks for the reply and the suggestions :slight_smile: I will try the baking for sure and see how it goes!
Again many thanks for the help. Really appreciate it!

3 posts were split to a new topic: How to Create Models with Sloped Roofs in Dragonfly