Timber gridshell bending simulation with Kangaroo

Hi guys,

I'm currently working on a script in order to simulate the construction of an orthogonal timber gridshell. The grid would be laid out flat on the ground and then raised into the desired shape (as the Multihalle Mannheim for example).

I have based my approach on scripts by Daniel Piker found in this discussion. There is also a video which is similar to what I want to achieve. The way I have set it up now is that I start with a flat grid and then move anchor points upwards to more or less the shape I want to achieve (functionally and esthetically). I then want the gridshell to behave as a realistic orthogonal grid would, hanging over and touching the ground at certain places. With this approach I aim to achieve a form that is physically feasible when working with a orthogonal grid.

Currently there are a few things that I have not set up in the right manner, I realise because of the anchor points (next to the building) it is impossible for the grid to keep it's desired shape. I do however want to keep it attached to the building as I go about moving the points. The main problem I am encountering is that I do not understand how to define an anchor point that is not neccecarily part of the mesh that Kangaroo acts upon, or maybe I do not fully understand the core principle of the anchor points. What I need is the grid to stay in shape (no change of length of edges) at all times, as if the bending force is extremely strong so to say.

I have attached two pictures to illustrate my problem and also the Grasshopper file. If anyone has some input on how to approach this problem I would appreciate it very much.

Kind regards,

Joris

Attachments:

1_initial.PNG, 20 KB
2_desired.PNG, 31 KB
Orthogonal timber gridshell simulation.gh, 19 KB

Replies to This Discussion

Permalink Reply by Daniel Piker on October 19, 2016 at 9:05am

Hi Joris,

It sounds like this would work better if instead of anchors you use some different constraints which do not conflict with the grid edge lengths. For example, keeping the vertices of one edge on a vertical plane, and perhaps pulling the other edge towards a curve.

I'd also suggest trying this using Kangaroo2, as it as a better selection of constraints and forces to use here. I'll post an example shortly

Permalink Reply by Daniel Piker on October 19, 2016 at 9:26am

Here's a starter for how to set this up in Kangaroo2.

For preservation of the edge lengths I often find it works best to keep this constraint fairly loose during the first stages of form finding, and then crank it right up once it is close to what you want.

I would also suggest you may want to consider orienting your grid diagonally, as it sometimes allows it to better form doubly curved shapes (see for instance the Weald and Downland gridshell).

Attachments:

K2Gridshell.gh, 34 KB

Permalink Reply by Joris Burger on October 21, 2016 at 2:57am

Hi Daniel,

Thanks very much for your swift reply. I will follow your suggestion to work with less rigid constraints and the set-up in Kangaroo 2 is also a big help.

As for the grid I was planning to have a diagonal orientation, just I was looking to simplify the model in this phase of the project. Thanks again and I will keep this post updated with my further progress.

Regards, Joris

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