# Acoustic panel ellipses - correlation between sections A-B1, A-B2, A-B3 etc. and the depth D1, D2, D3 etc

I am designing the acoustic panel. I try to make a solid difference in a stock material which is 400x800x24 mm with a milling

bit which is 19 mm in diameter.
I would like to make a set of ellipses in a top view (see pic 2) and make this pattern 3D as you can see in the pic 1.
I am planning to solve the solid difference by making a reverse correlation between sections A-B1, A-B2, A-B3 etc. and the depth

of the ellipses D1, D2, D3 etc.
The difference in depths of the ellipses is planned to be solved as as the number of offset milling paths.
The brep which I will use to make a solid difference is planned to be solved by Sweep1.

When I started to model my acoustic panel (gh file: E4_03) it turned out that there are a few problems.

1. The correlation of ellipses and their depths is opposite to the one that I wanted. The middle ellipses are the most shallow

instead of being the deepest.

1. Sweep1 creates a surface only with 1 rail curve. Therefore the ellipses in the middle of the panel cannot be sweeped.

I decided to turn the ellipses into 1 rail curves by the Trim regions component.
That made the internal ellipses able to be sweeped. However it turned out that there are some unwanted breaks between the

sweeped surfaces. > So I decided to make a double set of sweeped ellipses with a 30 degrees rotation.

1. Problems with the variations in the number of ellipses
Ex. when I want to have 30 ellipses instead of 20 (gh file: E4_032)

All the operations from pt 1 make my definition very complicated and not very flexible. Therefore in the variation E4_032 the

unwanted break is created (see pic ‘E4_032’)

Does anyone of you know how to rearrange my Grasshopper definition to obtain the form that I was planning?
Or mabye someone knows how to do it in a completely different way?

E4_03_gh forum.gh (69.4 KB)
E4_032_gh forum.gh (71.5 KB)
Kuka setup_work-table_Manufacturing Setup.3dm (13.8 MB)

I managed to get part way, but ran out of time this morning.

I hope this helps. Maybe I can find some more time over the weekend.

E4_032_gh forum_V2.gh (46.9 KB)

Thank you very much, Adam!
I made a solid difference.
You made a proper correlation of ellipses and their depths.
You also managed to simplify my definition in a huge way.
However, the middle ellipses are still not able to be sweeped.
If you solve this problem during a weekend, I will be really grateful.

This put up a bigger fight than it should have. For some reason there were lots of issues with Brep solid difference and unions, but I’m not entirely sure why. Some, would be fine, and others would not want to work. I had to add some workarounds to split divide some of the Breps before joining etc.

E4_032_gh forum_V3.gh (37.3 KB)

Wow Adam, thank you very much!
You made an amazing job!
I am really grateful to you!
Now I just have to get into this definition and understand the whole process as I am already a GH beginner.

No problem. Feel free to ask if you’re unsure about something in the definition.

Hey Adam,
I would like to ask about the ‘Shift Paths’ component which you used in your definition.
I have never faced to this component before.
How does it work in general? What is its particular role in definition?
I would be grateful if you could answer my question.

Some components add a level to the tree, some don’t. If you want to recombine different routes with different complexity, you need to make sure the the path structure matches.

You can either graft the simpler route, or you can use shiftPath to undo a unnecessary graft.

Hello again,
The new gh definition from Adam works almost perfectly.
Ihe problems no 1 (proper correlation between ellipses and their depths) and 3 (variations in the number of ellipses) are solved.
However I still have some issue with the problem no 2 (the ellipses in the middle of the panel cannot be sweeped).
When I am trying to replace the circular cross-section (pipe) with the milling bit cross section, the closed curves in the middle of the form still cannot be sweeped.
In the gh definitions which I attach all the open curves are sweeped properly.
However the closed ones still cannot be sweeped.
File ‘E5_02_gh forum’: no holes in the middle as the closed curves are not sweeped.
File ‘E5_07_gh forum’: the middle holes continue to have a circular cross-section instead the milling bit cross-section.
Does anyone have an idea how to solve this problem?

E5_02_gh forum.gh (45.8 KB)
E5_07_gh forum.gh (48.2 KB)
Kuka setup_work-table_Manufacturing Setup.3dm (7.6 MB)

Sorry, I just saw this post.

For some reason, GH doesn’t seem to like the first closed curve, although I’m not entirely sure why. If you rebuild the curves it seems to work. Also, if you use a high number of control points for the rebuild it shouldn’t differ too much from your original curves.

E5_07_gh forum_V2.gh (28.1 KB)

Thank you very much Adam! You did an amazing job!