Frei Otto's Compass Method - structual engineer

Hi guys,

if there are any structual engineers in this forum they already had heard the name Frei Otto. And for all the others:

He was a milestone in the formfinding of high complex building structures. He developed a method to generate a pattern on a surface more easier. This was in the 70's and of course there are much more easier ways to get those nets with GH, but i wanted to do it as Frei Otto did for a study.

To get those circles on a non planar freeform i took spheres and cut them with those surfaces.

So my main question or request is, if someone can have a look on my GH File to make it more easier or to find the mistake.

Moreover, i work with Anemone, but it doesnt really work if i want to do a loop in a loop, and i think this is very important for this task.

Thanks a lot.

Greetings,

Hendrik

Attachments:

Compass_method_v1.0.gh, 15 KB

Replies to This Discussion

Permalink Reply by Romain Mesnil on August 29, 2016 at 8:20am

Hi Hendrik,

it's a wonderful technique: it's extremely simple and yet it solves a difficult problem. Regarding the implementation, I would recommend scripting a component because you need to handle exceptions (and I am also not sure that trying to do nested loops in Anemone is a good idea):

The propagation can be stopped because the rhombi become 'flat', this happens in area of positive gaussian curvature. In this case, you need to exit the loop
You encounter a boundary, and you cannot trace a curve on the surface anymore...

A quad mesh with constant edge length is called a Tchebychev net. The research team I'm in has worked on this topic for quite a while now and built some gridshells in GFRP, if you need literature, you check those pages:

I realize I'm not exactly really answering your question, but I would definitely go for a short script if you want to use this in practical application. I hope this comment still helps!

Best,

Romain

P.S: The sphere/sphere intersection is the good way to do extend the compass method to 3D. Computing analytically the intersection saves some time (as you have to generate many spheres through the process).

Permalink Reply by Hendrik on August 30, 2016 at 2:10am

Hey Romain,

thank you for your answer and your interest.

Iam not that good in scripting, but i knew that anemone would be a bit to complex for that. Is there an easier way with scripting? Do you use Phyton or C#? Would you help me to to a little script? So i can learn how to do. It would be wonderful if you could do a little script for me to understand.

By the way: Very interesting Page and tests with grid shells. This is kinda work i want to do after my study. Currently iam studing civil engeneering for master degree in Hamburg, Germany, do you think you need a very interessted intern at your office? :)

Kind Regards,

Hendrik

Permalink Reply by Romain Mesnil on August 30, 2016 at 9:38am

Hi Hendrik,

sure we are always happy to receive applications! See our contact here and the page of the lab here.

Regarding the programming language, Python is considered easier to learn (it requires very little knowledge on scripting) but is slower as soon as there are loops. I usually go for Python for prototyping of algorithms, and then move to C# once I'm confident that the method works. If you are beginning with scripting, I would recommend Python.

I am preparing a lecture on management of complex geometries for a master at l'Ecole des Ponts in Paris. I wanted to include a case-study on Tchebychev nets on Python, it's not ready yet, I will upload it when I have some free time...

Best,

Romain

Permalink Reply by Hendrik on September 6, 2016 at 7:11am

Hey Romain,

is it possible you help me with my main problem? Scripting a short C#. I only want to make a quick overview how the compass method can be helpful in general and how to create it simply in GH. But i have problem to do it "simply" :)

Greetings,

Hendrik

Permalink Reply by Hendrik on September 21, 2016 at 1:36am

Hey Romain,

its not very necessary for me, but its a interesting method, maybe you can find some time for it/me?

Greetings,

Hendrik

Permalink Reply by Romain Mesnil on September 21, 2016 at 2:00am

Hi Hendrik,

you can have a look at this C# component scripted by Lionel du Peloux shared on our GitHub.

https://github.com/THINkSHELL/Compass

The script in C# looks like this:

https://github.com/THINkSHELL/Compass/blob/master/src/Kernel/Compas...

Unfortunately, I will be away for 10 days or so from tomorrow , so I'm not able to send you a simple working example in Python right now... I'll keep you informed when I go back and have some time to code that...

Greetings,

Romain

Permalink Reply by spiral on October 18, 2017 at 11:17am

links do not work, if there is an opportunity to share new links, I will be happy, Chebyshev's gridsshell and genetic algorithms are interesting to check in practice

RSS