Thomson Problem Modeling

[Harding_Rhyne]

Hi all, I am trying to model the thomson problem within kangaroo. The problem consists of charges arrayed on a sphere and they repel each other. I have (sort of) gotten points to stick to the sphere using the on mesh goal, and I have a negative strength on the magnetic snap goal, but the simulation simply isn’t behaving. Its as if the charges are not all uniform. Anyone have any ideas?

Kangaroo_ThomsonTest.gh (10.8 KB)

[DanielPiker]

You need a repulsion goal. Have a look at this reply and the threads linked in it:

Populate Geometry (global control)

Thanks It’s a goal for repulsion with a strength that’s a power of inverse distance - so strong when the points are close, falling off as they are further apart. You could also use elastic spheres (as in the SphereCollide goal) to push things apart, but there strength is a linear function of distance with a hard cutoff, and I find that the falloff from the power law repulsion often results in a nicer distribution. The problem with inverse distance functions though is that you e…

[Harding_Rhyne]

Thank you! This seems to fit my use case, but the script doesn’t seem to work. Outdated? I am on Rhino 8 and I have no idea on how to fix it. My coding knowledge is very limited. Is there a simple fix that I can implement?

Edit: Actually I think I got it to work.