How can i use kangaroo to change scissor grids between deployed and stowed state

Grasshopper
1

Hi everybody,

i got some problems with my scissor grid.
I created a double curved surface and now i want to translate it into a foldable grid.
The problem here is that the scissor mechanism does not overlap everywhere, because the surface is oriented differently depending on the starting point.
In addition these scissor elements shouldn’t be divided in the middle to reach more stability.
I already tried to use curve/sphere packing but I didn’t get the desired result.

I would like to animate the resulting scissor grid by using kangaroo but i don’t know how to make the whole system dependent on one module as I show in the picture below.
The intersections and length of the scissor elements should remain the same and not be divided.

I hope someone can help me with my problems.

Thanks in advance!

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scissor grid without overlaps

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scissor grid based on a double curved surface

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a module in detail, deployed state

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a module in detail, stowed state

grasshopperfile: 2018-12-25_ISD_scissor_grid.gh (14.3 KB)

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Hi @sim.kaiser,

Maybe you can try drawing insight(s) from some of these threads (if you haven’t already) for possible routes to get mechanics going:

maybe also look in kangaroo examples (GitHub - Dan-Piker/Kangaroo-examples: Example grasshopper definitions for the Kangaroo plugin) to check out other assemblies. Some may need upgrading to kangaroo 2.0.

'wish you luck!

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hi @René_Corella ,
thanks for the links!
Unfortunately I already know them and they couldn’t help me in my questions.
They are very two-dimensional and linear structures and not like my double curved surface.

1 Like
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Got it - speaking of, judging from your images - your grid cells appear to be four-sided as opposed to hexagonal?

Just wondering

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Yes, i now use four-sided instead of hexagonal grid cells, because the hexagonal ones affects the mobility of the system.

Sorry for the confusion.

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Your mesh needs to meet certain geometric conditions for such scissor structures to be possible - namely tangent incircles - this paper explains more:
https://cris.vub.be/en/publications/digital-design-of-deployable-scissor-grids-based-on-circle-packing(178d9be1-8ec3-4c57-bb5a-37db5a1a69d3).html

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Hi Daniel,
thanks a lot for your link!
That is exactly what I was looking for!
I read the whole script but it’s not easy for me to follow every step.
Unfortunately these are probably the most important steps.

How can i generate this tangent incircles for my whole mesh?
Is this possible without writing the whole code on my own (maybe the component from Kangaroo2 TanInCirc)?
So far I’ve only used container to build my skripts.

And do you also know a clean solution to animate the resulting structure with Kangaroo?
Maybe I overlooked it in your sample files for kangaroo :confused:

And finally a happy new year!

Thanks in advance!

1 Like
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have you found the script to help you at all?

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hi sim,
I have the same questions that you do. I have read the article about scissor grids based on circle packing, and followed Daniel pikers posts and comments all over the internet about circle packing and I’m still confused. had you find the definition and algorithms of scissor grids?