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In node tree A, I have a grid, instancing buildings, themselves instancing spheres on top of them.

I have an object, to which I applied node tree B. This one creates curves that I want to proximity interact with the spheres from node tree A, and just the spheres.

As far as I know I can only reference objects in a node tree. But what I want is to reference the position of specific instances from a different node tree.

Does it has something to do with attributes perhaps? Can they cross over node trees?

Thanks in advance.

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    $\begingroup$ Please prepare some simple example using two node trees, showcasing your problem. $\endgroup$ Oct 7, 2022 at 16:08

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You can achieve the desired result by assigning a boolean value to the spheres with the node Store Named Attribute in the first node tree.

If you then use the geometry created with this node tree in another node tree, you can query this attribute there again with Named Attribute, and thus separate the geometry from the rest and use your curves with it.

I have built a simple example for you here that illustrates this situation:

enter image description here

In NodeTreeA I create the geometry and select the spheres:

enter image description here

In NodeTreeB I separate this selection from the rest and modify the curve created there:

enter image description here


(Blender 3.2+)

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  • $\begingroup$ Hello @quellenform and thank you for taking the time. I feel that I'm almost there but can't plug the named attribute into the geometry proximity node. I cleaned up my file so you can have a look. the file Thanks in advance $\endgroup$
    – Enashka
    Oct 7, 2022 at 17:30
  • $\begingroup$ @Enashka You are almost there! First you have to capture a boolean value with Store Named Attribute in the first node tree to mark the spheres. And then you have to integrate the geometry created with this node tree in the second node tree with Object Info and separate the marked geometry. Exactly as I described it. Here is your modified blend file:: blend-exchange.com/b/vlMOv64j $\endgroup$
    – quellenform
    Oct 7, 2022 at 17:44
  • $\begingroup$ That workd thanks. Except that the curves also now attach to the ground, when I needed them to just attach to the spheres. A workaround I found is to separate each steps of my node tree into different objects referencing each other and reference the one with just the balls to my pyramid. $\endgroup$
    – Enashka
    Oct 7, 2022 at 18:04
  • $\begingroup$ @Enashka I'm sorry, that was my mistake now, I didn't look through the geometry carefully. You would have to separate the instances from the rest of the geometry first. I have a new file for you here: blend-exchange.com/b/LmSsKrNM $\endgroup$
    – quellenform
    Oct 7, 2022 at 18:10
  • $\begingroup$ That's it! Thank you so much! $\endgroup$
    – Enashka
    Oct 7, 2022 at 18:32

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