Catenary array help!

Hi guys!^^

I was trying to create a simple catenary array between two curves, in order to rebuild a form like the shell in the image (but defined with catenaries)... i'm not sure i'm proceeding well... it's the first time that i use that component. So, i need to create a sort of parabolic equation that determine the growth between each curve i think... how can i do that? There are 2 symmetrical curves... i'm not sure that i need to divide them...

I have also another problem with the Catenary component... as i read in some discussions here: the loft between the generated curves goes always wrong. Someone can help me?

Thx in advance,

PS: Do you think it's better proceed with Kangoroo? I never built a definition with that thing... it will be too much complex?

Attachments:

cat_proof.jpg, 586 KB

Replies to This Discussion

Permalink Reply by David Rutten on April 15, 2011 at 7:39am

Hi Marco,

there's no clear equation for creating a catenary with a given sag. You could use Galapagos to solve it for all of them though, but it might take a while as there are a lot of variables.

Oh darn, just found a problem with Galapagos in the most recent version. It updates far too often. I'll fix it, then release an update, then post an example of what I meant.

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Marco Caprani on April 15, 2011 at 8:01am

Thank you David,

mh... I think I underestimated the problem... It could be very difficult for me to find an equation for creating that thing. And also I've to learn more about Galapados before to use it for complex things..:P I will try in a different way, probably I will create the catenaries one by one, once that I've drew a spline that determines the heights of the shell, i'll have three points and so then i'll could draw the catenaries with a simple definition. What is the problem with Galapados? Thx for fix it :)

Permalink Reply by David Rutten on April 15, 2011 at 11:52am

The problem is that it solves the solution after every single slider change. So if you're solving for 20 sliders, it will take 20 times as long as it should.

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Dieter Toews on April 15, 2011 at 3:30pm

Hey David.

I'm just running into the same problem (& I need some stuff for my thesis presentation that's coming up). Would you be able to push this out soon as an updated gha or will you want to wait for 8.010? (ie should i revert to Grasshopper 8.007?)

Permalink Reply by Chris Tietjen on April 15, 2011 at 9:15am

Here's my take on it. I don't have the time right now to look at the progressive variation of the cat depth but I think it just requires a varying series into the 'a' input of the function component...could be wrong though.