Help needed for creating catenary structure in grasshopper

Replies to This Discussion

Permalink Reply by Pep Tornabell on April 29, 2011 at 5:49am

If you search around you will find some solitions. Giulio Piacentino has posted an scripted version that uses mathematical aproximation and works for multiple curves.

 

You can also approach this using form finding techniques, using some dynamic relaxation script or Kangaroo from Daniel Piker, a physical engine for GH.

 

Hope it helps

Permalink Reply by Daniel Piker on April 29, 2011 at 6:47am

While non-interacting catenary curves can be created mathematically, if you simply join together multiple curves created in this way, then the resulting structure will not be funicular as a whole.

Because they pull on each other at the points where they attach, the weight distribution is no longer even along the length of the curves. Therefore you really need an iterative technique.

 

This is just the sort of thing Kangaroo was made for

notice how the result differs from the smooth curve given by the hyperbolic cosine - it has sharp kinks where the curves attach.

 

(Definition attached below)

 

 

Attachments:

• catenaryexample.3dm, 44 KB
• catenaryexample.ghx, 147 KB

Permalink Reply by Sam Wood on April 29, 2011 at 5:09pm

Thank you this is perfect, I will have a play around with this and post what I come up with.

 

Thanks.

Permalink Reply by Sam Wood on April 29, 2011 at 10:10pm

Here's a few things I've been getting using this idea - does anyone have any other suggestions on a better output?

 

Thanks for the help

 

Permalink Reply by can cui on March 7, 2012 at 2:30am

Hi! I wonder why some of the connecting point will detach from each other when I start to run? how to confirm if they are anchored together before click toggle? Thanks !

Permalink Reply by Hannes Löschke on March 7, 2012 at 2:42am

Did you modify the original lines from the example?

Kangaroo springs connect only at their ends. The example is snapped to the grid and the curves are subdivided by half a grid unit in GH. This will guarantee a spring entpoint at wherever the input lines connect.

If you move the curves off the grid, kangaroo does no longer find the interconnection.

Permalink Reply by can cui on March 7, 2012 at 3:15am

haa... I see. that is a really crucial point. But another question comes, how to make sure both dubdived point intersect each other right at the crossing point.??which means the length of the both lines needs to be integer multiples of the subdiving segments?

Permalink Reply by Anna Doran on October 4, 2015 at 1:25pm

Hi Daniel,

Do you have an example how this works for kangaroo 2.02?

Thanks

Permalink Reply by Andrés Utz on April 14, 2020 at 11:37am

i have the same question...any idea?

Thanks!