Kangaroo Grab with Gumball?

I love the interactivity that the Grab component provides but it can sometimes be difficult to move the particles in specific directions, e.g. translate only in the x-axis, rotate around z-axis, etc. Is there a way to have more precise control like what we get in Rhino with the gumball?

I’m using Kangaroo almost every day, however for my use the Grab component rarely is much of a help. My typical workflow: modeling a base mesh with Rhino commands and this mesh is referenced in Grasshopper with Elefront. The mesh is being optimized with Kangaroo and if I need to adjust, I move vertices with the Gumball. I know it’s not exactly what you asked for but using Elefront to reference geometry from Rhino might be an option for you too?

If you want to move control some particles from your simulation precisely with the Rhino Gumball and Snaps, then the easiest way is often to create those particles as actual Rhino points, reference them, and set these points as Anchors in Kangaroo, instead of using Grab.

When doing this note you also need to distinguish between the P ‘point’ input of the Anchor and the T ‘target’.
It will often be helpful to internalise the P input in Grasshopper, but leave T as a reference from the Rhino points.
The point P tells Kangaroo which particle to anchor, and this needs to be coincident with the thing it is acting on, such as the corner of a mesh. You don’t want this to change during simulation as you move the Rhino point, or the anchor would become disconnected and stop working.
The T Target on the other hand is just where the particle is supposed to go. So you can have this as a referenced Rhino point and move it around without breaking the topology, even when resetting the simulation.

If that isn’t clear, let me know and I can make a video to try and show it better.


Didn’t think of using Anchors. That’s a great idea, thanks!

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