Forces control at each anchor point

Hello everyone! I am preparing a form finding lecture for my architecture students and I want to show few samples using Kangaroo. My question is: How can I control the forces at each anchor point? How can I assign different forces at the anchor points in order to simulate different cable tension?

I am modifying the values of the SpringsFromMesh to simulate edge cables, however I need to be able to assign different values to the AnchorPoints.

This is what I have done so far, I believe the changes have to be done here at the AnchorPoints, but I am not sure how to work on it.

So, if somebody have an idea or have done it before, please give me a

hand on this.

Thanks so much!

Romualdo

Replies to This Discussion

Permalink Reply by Daniel Piker on August 3, 2014 at 11:03am

Hi Romualdo,

Anchor points in Kangaroo are defined as being completely fixed - they will not move, no matter what forces are applied to them, and forces applied to them will have no effect on the relaxation.

It looks like what you are after is actually a way to change the tension in the edge cables relative to the tension in the interior of the mesh, as this will change the radius indicated in your images. For this you need separate springs for the exterior edges.

You can use the E1 output of the 'Mesh Edges' component to get these. If you want different tensions in the edge cables on the different sides, you can join these edge segments into a single polyline, then split it at the 4 corner points.

Permalink Reply by Romualdo on August 3, 2014 at 2:56pm

Hi Daniel,

Thanks a lot for your fast response.

It is more clear for me know, even do it’s a little more complicated than what I thought, with my poor Grasshopper and Kangaroo experience, but I want to try it anyway and let you know of my progress.

Here is an image aligned to your answer. At pre-tension stage, once the corners are fixed at a point, the method of applying tension to the edge of the surface material is by applying forces to the cables at each end point of the corner plates.

I am very, very appreciated with your answer. Thanks again.

Romualdo

Permalink Reply by Romualdo on October 3, 2014 at 5:43pm

Hello Daniel, Thanks for the ideas, I finally did all the Membrane Structures basic forms using Kangaroo. As you can see I manage to change edge tension and also did fixed edges. You can see the Form Finding’s results in my 2^nd and new Book: “Membrane Structures: First Steps towards Form Finding” at www.membranasestructurales.com

Let’s keep in contact, also in few weeks I will like to send you a copy of the book.

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