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I’m struggling with geometry nodes. I had a node group that generates a flower-like object based on parameters. Each copy of the node group generates a separate set of geometry which I can join to generate output. But I want to drive the node group from within another one; I want to create geometry, like a grid or a specified mesh, and have each vertex run the Parameterized Flower node group with a different set of params — some math on the vertex position for the group’s Translation param, an index number for the number of petals or one of the other input params, etc.

When I wire up my node group, the output is Geometry. But the Point Instance node in the outer group only accepts objects or collections (the yellow arrow in the screenshot), so I have to manually duplicate the node group and send its output to a Join Geometry node:

enter image description here

This defeats the purpose — I want the duplication to be generated. I’m looking for a way to only have a single copy of the Parameterized Flower group generate a separate, unique object at every vertex on the supplied geometry.

How do I get there from here?

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It's not possible to instantiate geometry that's not tied to another object in the Point Instance node at the moment, but it is planned for a future version. It is a known limitation right now.

As a workaround you can use a collection with pre-generated objects and uncheck "Whole Collection". Tweak the node seed to randomize instances. Each element of the collection should have equal chances to be instantiated. I think weights similar to the particle system settings are planned.

enter image description here

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    $\begingroup$ And there's no way to convert the output of Point Instance to generate a new object rather than Geometry output at the moment -- I think I see the problem. Well, that's a major blocker for the work I want to do, which relies heavily on sending parameters to subroutines to generate variations on geometry. I guess I'll go back to Sverchok and Animation Nodes for now and see if I can get any further. Thanks for the feedback $\endgroup$
    – Val
    Apr 5 '21 at 22:37

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