Kangaroo2 grab and lock function


I’m wondering if the option to grab and lock vertices with the Kangaroo2 ‘Grab’ node has been removed.
I am able to grab and temporarily lock one vertex, though if I go to grab another the last locked vertex moves from its locked position.
Am I missing something in my sequence of key/mouse clicks? Or has the option to lock multiple vertices in place with the Grab node been removed?


Hi Jason,

Yes, I’m afraid the Lock function is removed from the current version of the Grab component.

The way the Grab gets the mouse events has gone through quite a few different versions under the hood, so it now doesn’t need any key presses to drag points (which was problematic for having it work on both Rhino/Mac).
Any mouse interaction also needs to avoid interfering too much with normal non-Kangaroo Rhino interaction. I seem to remember this part was making adding back in the right click to anchor grabbed points behaviour tricky. I’ll have another look at it though. You’re the first person to ask, so I had thought maybe nobody used or missed the old locking behaviour.

It might be that I can also suggest some workaround in the meantime (maybe using snaps or anchors toggling on and off) if you can describe what it is you want to do.

I see, that’s too bad. Though if I’m the first one to ask, I guess it wasn’t being used that often.
In that sense it makes me think the work we are currently doing is quite novel.

The environment I have been trying to stage in Kangaroo2 is for our current research work on bending active structures and ice shells. Basically we have a setup where the ‘Rod’ node is being used to mimic GFR rods physical properties, whose formal geometry takes on a doubly curved shell. The inside of this shell has a series of woven lines, that mimic tensile steel cables, linking the intersections of the rods together for more stiffness when a load is placed on the model.

Because I am effectively trying to to ‘sculpt’ this structures vertices, to effect the overall geometry of the system, the lock option for ‘Grab’ would have helped when strategically moving a few vertices to a new position. Your point about Snaps is an option, I’ll just have to construct that new geometry to snap the existing intersection points to…

Thanks for the quick reply.

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I’m reviving this…

Daniel, did you ever make some code about drag-and-lock kangaroo particles like in the old solver?
Do you remember doing some cusom goal object about this?

If not, can you suggest me a way to build it myself?
No need for actual code (but it’s always welcome when you ever do so), just pseudo-code is enough or even textual description.
Would you replace “Grab” goal component entirely with a cusom one?
Or would you make a custom “Anchor” component that locks only some particle? (but then, how to detect which particle is currently dragged by the mouse cursor?)