Kangaroo Water bubbles :)

Hi @DanielPiker,

After a week of working with Kangaroo , I now think I know how to work with it, thanks for your help.
Even got the step solver working.

Can I ask I hope last questions (for a time being):

  1. Am I correct in saying that Kangaroo is not physical calculation/ analysis tool. It is a form finding tool. For a example there is no reason for me to use real gravity to get to the form I want? I need to find a form first and then use different structural and material analysis tools on it and iterate until I got a desired result.

2.What will you recommend (plugin or approach) to set a specific parameters to structural members. Say I have a bending rod or plate, how would you specify max bend factor for wood or sheet of metal?

  1. In step solver how to sync number of iterations with animation slider? So it animates until kangaroo is converged.

4.For some reason I was avoiding Kangaroo fro a long time, but you have created an amazon tool. The only thing is Mac version is super slow (it is not interactive). Do you have timeframe for fixing it? And is Kangaroo still in development?

Once again thank you

Great to see your progress.
To try and answer your questions:

Kangaroo is primarily a form-finding tool, but it can also be used for analysis with real values of material stiffness, load and deformation, for certain types of structures.

When form-finding there is no need to use real values for gravity or stiffness. Just like Otto, Gaudi and Isler making models with hanging chains and inverting to find compressive forms, or dipping wires in soap to shape tensile membranes, it is not a direct simulation of the building materials, but a process which makes use of key physical behaviours of the model material to generate a geometry with particular properties that will be useful for the later actual built structure
(the chain does not resist bending, so hangs in a shape of pure tension, the soap film stretches into a shape with equal tension in all directions).
The actual magnitude of the tensile forces in the chain or soap are not important for this step.
(though if you want to be really accurate, you do need to pay some attention to how you set up the relative weight and stiffness distribution in the form-finding simulation)

For analysis you can set real material stiffness values and get numerically meaningful deformations for things like cables, space frames with only axial forces, and bending rods in Kangaroo. See here for another thread on this. There is also a Grasshopper plugin by Cecilie called K2Engineering which uses Kangaroo and adds components to make setting up these simulations with real units and materials easier, with more tools for pre-stress and analysis.
For more detailed analysis of things like plates, shells and beams in Grasshopper, I’d recommend looking at Karamba. For volumetric analysis of solid parts I’d recommend Scan-and-Solve

For capturing animations using the slider and the Step Solver, one thing to be aware of is that for the ‘Animate’ input parameter, the actual value isn’t important - it only matters if it is zero or not. It is just a way of making use of the built in slider animate function of Grasshopper (which automatically updates a slider in increments and captures a frame for each). As long as the slider starts from zero, it begins by resetting the simulation, then each time the slider updates(to any positive value) it triggers a Kangaroo update (which means as many internal iterations as you have set in the ‘SubIterations’ input).
The way I generally use it is to move the slider around manually to see how many iterations it takes to reach the point in the simulation I want the animation to stop at, then right click the slider and choose animate, setting the frame count to this number of iterations divided by my SubIterations setting.

Finally, about the interaction speed in Mac. I do want to fix this, but I’m afraid I don’t know enough yet about what causes the issue to know how long this might take.

3 Likes

Hi @DanielPiker,

Thank you for detailed explanation, very helpful. I found an old Kangaroo manual online it helps as well, unfortunately it doesn’t describes all the components. But to be honest springs and rods will be more than enough just now.

It is what I did as well :wink: thought maybe you had a different approach))

Do you need any help testing on a Mac? I can help.

perhaps Multi-Agents Works

Hi! Super thanks for posting this solution :heart_eyes:! I am also working on similar effect (some marbling drawing effect) but wanting more fluidity for those bubbles. Could you tell me where I can strengthen the fluidity or maybe elongate the time that those bubbles return to original shape? (sorry for maybe stupid question… just begin to learn kangaroo)