varying force on chain

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Permalink Reply by Marc Syp on March 17, 2011 at 3:00pm

 

Just use data matching the same way you would with any other grasshopper component.  For each node, you will generate a different corresponding force vector.  Note, though, that you can't use path structures with the old kangaroo, so make sure you flatten your lists of nodes and forces and make sure they are in the correct order.

 

Marc

 

Permalink Reply by Georgi Petrov on March 17, 2011 at 3:07pm

Thank you for the quick reply.

 

It seemed to be responding only to the first value when I was trying it out before writing.  But my forces weren't big enough so I didn't notice any change.

 

Do you know what units this works with?

 

thank you again

Permalink Reply by Nick Cole on March 18, 2011 at 2:15am

I'm pretty sure it works with whatever units you want it to but you have to be consistent. So, if youve drawn your model in m then you have to use m for your length scale. If you then want to input forces as kN then you need to make sure that your stiffness (and damping if you want to model real behaviour) is also in kN and m. You're output will also be in kN and m. Another thing that's worth bearing in mind (and Daniel correct me if i'm wrong on this) is that if you model in mm then you might have to use a smaller time step as the extra significant figures for mm can cause it to become unstable slightly earlier than if you were using m. This could slow the form finding down but would tend to give you a more accurate final answer.

Permalink Reply by Georgi Petrov on March 18, 2011 at 8:02am

Thank you for the explanation.

I'll be more careful about keeping things in the same units.