Creating a closed brep based on a scan


Dear Rhino community,

I am fabricating a fully parametric earbud in Grasshopper. The earbud is fully personalised and is based on a scan. I have my design, and it consists of three surfaces. These surfaces should form a closed brep. However, it is open. In this Grasshopper script, I create my own vectors, but I know the surfaces will never be seamless using this method. This is why I need help. I can’t figure out how to make a watertight brep here. I need this closed brep because later in my script, I will use a solid difference for the creation of the case and mold. The challenge here is to make it in Grasshopper, and not use Rhino Common. Any help is greatly appreciated!

Please find me script here: Earbuds question.gh (2.2 MB)

You can use mesh boolean difference. No need to use nurbs…

I looked at your definition just now. I’m on Rhino 8 and I don’t use the Flexibility plugin you used for QuadRemesh and toNurbs. What Rhino version are you on?

With the default QuadRemesh settings and no special toNurbs, the resulting brep is closed.

Let’s assume your three surfaces do not join into a closed brep, you can use ShrinkWrap to create a watertight mesh around your earbud. This can be 3D printed.

Earbuds.gh (2.2 MB)

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Nice! Works in R7 with no changes (“Closed Brep”). :+1:

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But the result is a closed Brep.

Hi Martin,

I’m on Rhino 7. I swear when I uploaded the brep was open :sweat_smile:. But I now indeed see that it is closed on my laptop as well. I’m for sure going to implent the ShrinkWrap tool as an added security measure to make sure the mesh will always be closed! I’m downloading Rhino 8 as I’m typing this haha.

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But here when I change the value to a very low value, let’s say 10, it does give me an open brep. This is because the whole script is based on my own creation of vectors, and therefore my own creation of the surface tangency.



image

However, when I make this value very high, let’s say 250, and I would hypothethically want the top surface to have sharper curves, I get creases in my brep.


I’m wondering if there is another method of using the tangency of a cut off mesh/brep to continue building upon without any margin for failure.