# Kangaroo2 - simpel Spring model

Hi,

Fairly simpel Kangaroo question:

4 points, 3 springs.

points 1,3,4 are ‘fixed’ anchor points, only point 2 is ‘floating’.

I would like to ‘pull’ on all curves with the same force, and see where point 2 goes to make equilibrium.
2023-06-27 Simpel spring model.gh (8.7 KB)

Below is what I would expect, in green.

Anyone a suggestion how to make an Kangaro model of this? (I couldnt find tutorials for using spring/anchors for cables :(.

Many thanks!

Here’s how you’d turn those lines into springs (with zero rest length)
2023-06-27 Simpel spring model.gh (11.8 KB)

2 Likes

“simple”, not “simpel”.

Funny, it’s the same as the average of the three points? I thought maybe if was a point equidistant from all three points? But I believe you!

simple spring model_2023Jun27a.gh (11.9 KB)

2 Likes

Yes indeed, equal strength zero rest length springs will give the average of the 3 points.
This is conveniently the same as the point which minimises the sum of the squared lengths.

I should also add that in the question the poster asked for all lines pulling with the same force, which isn’t strictly what’s happening in my first answer, because the more stretched springs are under more tension. For the forces to be the same magnitude we’d want not springs but ConstantTension goals, like this:

2023-06-27 Simpel spring model.gh (15.0 KB)

The point then ends up so that the 3 angles are all 120°
which is also the point which minimises the sum of the lengths (instead of their squares like with springs)

2 Likes