Join Brep to create unified Offset Surface

Dear Community,

I am currently working on my thesis project and struggling with the part where I want to join different surfaces, which are created using the same curves, so I can offset them in a unified way. Right now, I have five different surfaces which, for whatever reason, simply don’t want to merge, so they are offset separately and create overlaps that I don’t want. I don’t understand why I cannot join the surfaces, even though I am using the same edge curves. Do you have any suggestions on what might help? The goal is to have one solid union in the end. Thanks a lot in advance, I really appreciate the help!


BrepJoin.gh (46.5 KB)

I have seen this problem many times when creating complex boat designs. What works for me is to start with one surface and use its edges to create the next surface. Brep Edges

1 Like

Thanks again for your advice. I have to admit, I didn’t know this feature existed, it’s super helpful! I just gave it a try and it still doesn’t work unfortunetly. Maybe I’ll find a different solution or maybe you know a different approach as well?

I don’t have your plugins so can’t work on your geometry but using surface edges definitely can work.

BrepJoin Edited v0.gh (72.5 KB)

Rebuilt the section curves.
I eliminated the plugin component
You can not simply offset like that, not possible for your shape

From what I can tell, the Sweep2 fails to Brep Join while a RuleSrf instead works.



BrepJoin_2024Oct24a.gh (45.7 KB)

I don’t know how offset surface works on a polysurface (Open Brep) to get thickness :question:

Thanks @Quan_Li and @Joseph_Oster. Joining the Brep already helps a lot. I tried baking the surfaces, joining them in Rhino and offsetting them just to check, if there is an issue with the geometry. But in Rhino it seems to work, I just can’t figure out why the Offset Surface doesn’t work in this case :slight_smile: Again, thank you very much for the help

Offset Surface works on one surface (or face of a polysurface) at a time. Adding thickness to a polysurface is the holy grail of CAD problems. Not always easy to do.

How does it work in Rhino?

oooh I see, I coming from Solidworks and it’s so easy to implement there, so I thought maybe it is similar in Grasshopper or Rhino.

In Rhino I baked the surfaces, joined them and then just hit the command OffsetSrf. It’s not entirely perfect but here is how it looks:


Does it help for you to see the Rhino file?

No, I can do the same thing. Not entirely perfect, indeed! I didn’t know Rhino could do that.

1 Like

By the way, I tested only R7 when I made that comment. R8 seems to work much better. :+1:

1 Like