Dynamic effect or Iteration?

Hi guys,

I'm fairly new to kangaroo and I'm just trying to get an accurate model of a chain under gravity, which I think I've achieved but probably gone the long way about it. I'm defining the two end points of the chain in Rhino so that I can move them to any point and the chain will reform, with gravity acting on its new length. I'm not sure if this is mentioned or documented somewhere but when I move the points around in Rhino is the fluctuation, before the chain settles in the hanging position, due to a dynamic effect or is it just the iteration defining the new hanging position of the chain?

I hope this makes sense and cheers for any help! I've also attached the grasshopper file.

Brady

Attachments:

Attempt 3.2.gh, 11 KB

Replies to This Discussion

Permalink Reply by Michael Makris on April 16, 2013 at 6:23pm

I you're running Kangaroo on a timer, it's definitely a dynamic effect. If you're running Kangaroo on the "sequence" tool, it resets the whole simulation any time you change anything.

Permalink Reply by Brady Williams on April 16, 2013 at 6:39pm

Excellent, thanks heaps! I am running it on a timer so I was thinking it might have been a dynamic effect, but I thought I would make sure of it. Thanks for your help and quick reply!

Permalink Reply by Daniel Piker on April 17, 2013 at 2:19am

Yes, Kangaroo uses the dynamics to reach an equilibrium. Potential energy due to gravity/elasticity etc gets converted into kinetic energy which moves the points. The new point positions change the potential energy, so it bounces around, converting back and forth. Damping takes out some of this energy, causing these oscillations to decrease in size until the system reaches an equilibrium position where the different forces acting on each particle balance out.
Often it is this final state you are interested in, not necessarily the kinetic effects while getting there, and there are other techniques which give you only this, but the thing I like about the dynamic approach is the connection to real world physics, and sometimes seeing this movement helps us understand the system better to be able to adjust it to get the final forms we want.

Permalink Reply by Brady Williams on April 17, 2013 at 2:29am

Thanks Daniel, that's an excellent explanation and really helped get my head around it. I'm looking forward to seeing what I can do with beam manipulation using kangaroo. It's a very exciting program!

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