Hi Rasmus,

Interesting work. I think you are heading along the right lines with the spring connection.

A few additions I would suggest though :

Split the mesh so you have a vertex in the middle of the strip at the connection point. In fact, maybe try making the mesh along the whole strip symmetrical by splitting each rectangle into 4 triangles instead of just 2.

With just one spring between the 2 strips you have an elastic connection between their positions, but no constraint on their rotations.

I would suggest using some bending forces like this:

where the red squares represent a bending force between their 2 adjacent edges, with a rest angle of pi/2

This gives some resistance on 5 of the 6 degrees of freedom between the 2 strips, but leaves them free to rotate about the axis of the bolt, which I presume is what you want.

Alternatively, if you want the strips to actually lie on each other without any spacing, you could model it like this:

where the yellow line is a spring connected to both strips at one end and free at the other.

and there are still 4 perpendicular bending forces between this line and each strip.

This gives a hard constraint on the 3 translational degrees of freedom, elastic resistance on 2 of the rotational dofs and free on the last 1.

I hope this helps, let me know if you have any problems modelling this in Kangaroo.

As I've mentioned before - I am working on giving each node 6 degrees of freedom, which would mean you could model each strip as just a polyline, and specify directly the rotational constraints between any pair of particles.

http://www.grasshopper3d.com/profiles/blogs/latest-version-of-grids...

there is a component for gridshell generation, try to link this to kangaroo with the surface elements...i think...