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Using Geometry Nodes, is it possible to get the Vertex Colors of two separate objects with the same topology, and mix them?

I know mixing of colors can (obviously) be done in the material, but I am thinking of linking Vertex Color change to a mesh deformation that occurs inside GN.

I also realize that getting Vertex Color data into GN is simple when the data exists on the same object the GN modifier is on. (Just plug in an input socket and specify the Col attribute in the modifier.)

But getting Vertex Color data from another object, I'm not so sure about. The Object Info node doesn't have an output socket for this. Maybe the attribute can be captured from the Geometry output socket's data, but I haven't had any luck with that so far. Thanks.

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In Blender 3.2 you can get this value via Named Attribute.

This node gives you the vertex color of the selected geometry.

enter image description here

If you then process this accordingly and store it in your target geometry with the node Store Named Attribute, you can use it in the shader.

However, you can only access them directly in the shader via Color Attribute if you have previously created an attribute with the name "Col" in the geometry that contains the Geometry Nodes.

Otherwise you would have to query this attribute in the shader with the node Attribute.


(Blender 3.2)

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  • $\begingroup$ Thank you! :-) I noticed the Store Named Attribute node in your example uses Vector instead of Color. Is that simply because in effect they are the same in this example? Also, my Transfer Attribute nodes have a drop-down selector for Color, Vector, etc., but I noticed yours do not - although we are both using Blender 3.2... any idea what's going on there? (At first I thought yours were hidden, but it's not that.) $\endgroup$
    – Mentalist
    Aug 10, 2022 at 2:40
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    $\begingroup$ @Mentalist Oh, sorry about that, it's a bad habit of mine to save space: If the node options are self-explanatory or on default settings, I usually hide them with Toggle Node Options. And yes, here in this example it doesn't really matter if Vector or Color is selected, but I fixed it so there's less misunderstanding. $\endgroup$
    – quellenform
    Aug 10, 2022 at 8:44
  • $\begingroup$ Oh, I see. It's in the Node menu. I had no idea... learned something new. Thank you for clarifying. $\endgroup$
    – Mentalist
    Aug 10, 2022 at 10:40

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