Self-weight in kangaroo formfinding

Hey guys, I have a question about implementing selfweight during the kangaroo formfinding. Is it somehow possible to adjust the self-weight loading after each step of iteration? For now Im using the solution on the following printscreen. It works basically quite well, but in case of larger deformations it starts to be inaccurate, because it still takes the weight of triangles from undeformed mesh. Is there a way how to adjust this solution so it will use the triangles from deformed mesh to determine the load? Thank you for your answers, in attachment there is also gh file with necessary coordinate txt files.

Filip

Attachments:

quest3.zip, 42 KB

Replies to This Discussion

Permalink Reply by Daniel Piker on March 8, 2016 at 12:05pm

Hi Filip,

This is exactly what the AreaWeight component you are using is already doing.

It generates a force which changes at each iteration to be proportional to the current area of each triangle, distributed across its 3 nodes according to tributary area.

(as shown here)

Permalink Reply by Filip Smejkal on March 8, 2016 at 12:09pm

Great, thank you!

Permalink Reply by Nik Willmore on March 8, 2016 at 12:13pm

I'm confused. Doesn't real gravity act the same way, not caring about mesh orientation and just pulling down at a constant force for each bit of mass? Pictures would help when I'm away from a computer on a phone.

On a big planet the force of gravity is essentially fixed with distance at an architectural scale, so it's not gravity that must be your problem.

Ah, I see a former discussion and the related answer by Daniel here now about triangle size actually changing for an elastic material.

http://www.grasshopper3d.com/forum/topics/formfinding-with-kangaroo...

Permalink Reply by Daniel Piker on March 8, 2016 at 1:13pm

It's a fair point though, and worth noting that the AreaWeight component is for formfinding, not simulation (since the total mass increases as the surface stretches out, to maintain constant mass per unit area, instead of thinning as it stretches and maintaining constant total mass like real things do).

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