Multiple Breps into one

Rhino
1

I have one part contains 1 cutout vertically. Ideally the part is one, But after the cut it has two Breps. While exporting into STEP, if forms 2 breps that makes my pre processing difficult. Is there any way I can bake them like a single Brep?

Thank you in advance.

2

Hi Abhilash -

I’m afraid it’s impossible to help you based on the description here. Please post the 3dm file.
-wim

3

in the step options there is a checkbox for split closed surfaces, you might try unchecking this, understanding of course this can cause data transfer issues with some programs.

4

image
image770Ă—409 10.1 KB

Thankyou Wim, My part will look like this. The part has multiple bodies. But during export I need to name it for the further simulation automation part. My requirement is all bodies in this part as one Brep after exporting from Rhino. Rhight now its exported as individual Breps = No. of bodies.

5

Hi Kyle, My assembly has more than 1800 parts. I was planning to group together with all the bodies that belongs to its own parent (parts). My reference assembly in Creo contains 100-150 parts, But it has cutouts that makes inside part itself creating separate bodies. In creo it doesn’t matter. But in Rhino this Brep union doesn’t work regardless of any operations unless the bodies are touching each other.

The option split closed surface should be applied during Save file. I assume we should do something before saving.

6

ah, ok I was not clear on what you were doing… disregard my suggestion.

in Rhino you can group objects or layer objects together, there is no option (to my knowledge) that allows you to have disjoint objects joined to be considered as one brep.

most programs that import step will respect grouping and layering.

7

there is _nonManifoldMerge
the help claims
This generally only useful for export to analysis programs

but i think it s best to look at the importing program to get the correct import, not force an unconventional export… but give it a try. (backup / save all files before, maybe start with 20 breps, not 2000…)

which program will receive the exported data ?

one brep consisting of nearly 2000 dices:

Screenshot 2025-10-07 at 22.09.06
Screenshot 2025-10-07 at 22.09.062970Ă—1810 2.27 MB

OneBrep1980Dices.3dm.zip (2.3 MB)

8

Thank you, Creo will receive the export data. But can we do it with grasshopper component? I have fully created the model with the script. So that every single itererations in the model I can easily export without working inside Rhino window.

9

does it solve your issue ?

you have to do a scripting component and use Brep.MergeBreps

nonmanifoldmerge.gh (7.2 KB)

10

Dear Tom,

You saved my life. Thanks alot.