Kangaroo Kinematic System

26%20PM Hi all-

New here to the forums, and relatively new to Grasshopper. I am trying to simulate a drawing machine, similar to a harmonograph or pantograph. I’ve read these ones here:


The difference is I would like to create the simulation using physics simulation with Kangaroo. I think I’ve go the right idea going, but could use some help fine-tuning it, as it’s not behaving exactly how I want, especially with the timer running. I’d like to make a flexible script so that I can increase the complexity (number of line segments), and it still works physically

Here is my file:
ND_DwgMachine_01.gh (13.7 KB)

Here’s is a screenshot of what I’m aiming for:

Many thanks in advance!

Ndebru20.gh (23.5 KB)

ND_DwgMachine_01_dp.gh (13.0 KB)

Here’s a way of doing it that should make it easier to modify the parameters while it is running.
Anchors have 2 inputs - P is the initial location of the points you want to anchor, and T is the position you want to fix them in. Ideally here we only want to move T while the solver is running.


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Hi Mahdiyar,

Fantastic, thanks for your thoughts. This shows that i was indeed sort of on the right track, just needed to sort out a few things with the anchors. Thanks for showing me the way!


Hi Daniel,

This is really helpful, thanks for your input. This is a really elegantly simple solution.

Next step I think would be to try to rotate the drawing plane as the points are being recorded… I will give this a go and update again with the progress.


Hi again. Okay, I’m stuck again on this project with a new problem as I’ve been trying to increase the complexity.

I can’t figure out why the bending goal isn’t working on these lines, which are meant to align, as illustrated below:


Here’s the script:
ND_DwgMachine_06.gh (25.9 KB)

What seems to be the problem? Any advice or suggestions would be most welcome.