Extending rod simulation in Kangaroo

Grasshopper Kangaroo
1

Hi everyone,

We are doing some form-finding exercises and are working on a bending-active structure which we try to simulate in Kangaroo. We are trying to simulate rods that are anchored on one end and are pushed on the other through a static ‘slider’. As the rods are being pushed, they extend and lift up. The second part of actuation is less complex and is just a cable pulling on all the extended rods and thus pivoting the structure on its anchor points. Attaching a gif of a scale model that we are trying to reproduce in Kangaroo.

image8_resized

We are defining rods with simple polylines and we thought that by extending their length (moving one of the middle vertices away while the end vertices stay in place) we can somewhat simulate a similar scenario, however every time an input polyline changes the simulation resets.

Anyone has an idea of how this could be achieved?

2

Hi @mase1871
It’s hard to say exactly without the definition, but generally to modify the simulation properties with changes to the inputs without resetting the geometry, you should change things like rest length, rest angle, and target point for Anchors.
If you change the actual points defining the geometry, then these get registered as new points in the simulation and create new goals instead of modifying the existing ones.

3

My bad, attaching a clean version of demo.

Target points for anchors sounds like a viable solution, however I have no experience with these. Could you elaborate?

demo.gh (35.8 KB)