Foldable Structure

Hi guys! I’m trying to do a deployable structure that fold on itself and can be packed into a cubic box. I'm facing a problem: when I try to fold, I want to maintain the length of the pipes, corresponding to the distance between the points (the mountain points move in x axis and the valley in both x and y axis), I really need to "lock" the dimensions or when I move the X dimension, it increases the Y using the same value. Any ideas?

Thanks

Attachments:

Structure.gh, 53 KB

Replies to This Discussion

Permalink Reply by Tibbar Looc on July 26, 2014 at 8:54am

Hi,

The variable 'Movement Control' here operates both the base size and height of the pyramids in different scales.

If I call this variable as X, and the folding units as 'pyramids', where for each pyramid, the length of the sides of the base are A and B and the height is H and corner to top point lines are 'pipes', like you mentioned:

In the current system, the relation of X to one of the base sides is a 5X multiplier (not exactly, but something like that) and to pyramid height is a (3-X)+0,3 multiplier (where 3 and 0,3 are also other variables).

HOWEVER, if you want to keep the pipe length fixed for the pyramids, the correlation between the base and height is a constant, which is (if I didn't calculate it wrong) (A^2+B^2)/H. THIS IS TRUE AS LONG AS EACH PYRAMID IS SYMMETRICAL ALONG U AND V. If they are not, which is your case, I don't think that the pyramids can fold along a single line altogether without altering the pipe size.

So, to keep the pipe length fixed, one solution maybe to create symmetrical pyramids and align them parallel to the movement axis while also creating the base/height relation. That's my two cents...

extra note: By symmetrical, I don't mean a square pyramid. It can have any rectangular base as long as the apex is somewhere along the base center normal.

Permalink Reply by Kikas Palma on July 26, 2014 at 7:15pm

Thanks for the reply!

I followed your advice and changed my apex to the base center, I have the relation between the base sides of the pyramid but I keep failing when I try to do the constant, probably because I'm not doing it correctly! I can find the variables but when I evaluate the expression it gives me ridiculous numbers! can you take a look?

thanks for your time

Attachments:

Structure.gh, 57 KB

Permalink Reply by Tibbar Looc on July 27, 2014 at 11:55am

I just wrote a long explanatory post but it went to internet limbo.

Need to keep it short now, please see the file attached:

* I made a mistake for the formula, it should be like (A^2+B^2)*H^2 should stay constant. For a uniform length scale of S for A and B, the height should be 1/S times. But in your situation the pyramids are scaled along a single axis, the corresponding formula is in the file.

* The main problem is the loft which is the envelope for the pyramid bases. It needs to be become something like an extrusion, which has the same section for every x value. That was what I was trying to mean by aligning. I didn't change the loft not to interfere with your design.

* Also you marked the centers of subsurfaces instead of pyramid bases, which is not the same.

* The pyramid heights in the attached file are meaningless, you can create different heights anyway you want as long as you keep the length multiplier formula in the end. You cannot use the move control variable twice for the height (once to determine the sides, once again for the height which is already operated by the sides.)

After changing the envelope and correcting the center points, post the file here if you still have a problem and I will try to find out what I did wrong. Also, I would love to see if you can find other solutions.

Cheers.

Attachments:

StructureX.gh, 64 KB

Permalink Reply by Kikas Palma on July 31, 2014 at 4:06pm

Hi!

Still struggling with it! I tried everything I could, but the problem is that I really have to keep both uneven pattern and this geometry and It's making my life really hard! The way you did it, though it really helped to achieve a better solution, doesn't work the way i need it to be, the height becomes uneven, and i need it to be 0.3 for all when deployed! I used the pythagorean theorem to find the relation between the height and the edge of the pyramid. To do this I found the half diagonal of the base and used a cluster so I could have the distance of the edge in the deployable structure (like the real dimension of it), and with this I should be able to found the height of each pyramid, but I dont know why my expressions dont work (probably they're wrong! I used -- half diagonal of the pyramid base^2 - pyramid edge^2 = sqr root of pyramid's height) and when i try to do all the operations it just stops! argh
Would you mind to take a look (again)?

Sorry to bother

Cheers

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