I've created a Group node that acts as a geometry switch. Plug in a few different geometries, and the integer you give it determines which geometry actually comes out. It works fine with a Value input, but I want to give it a random value. Feeling clever, I assume this is what the Random Value node is for... however when I connect it the output wire turns red.
Looking to the Blender Manual, I tried to understand more about how the Random Value Node works. The ID input socket is perplexing me:
Random Value Node
An ID to drive the random number generator seed. By default, this input uses the same value as of the ID Node, which is the id attribute of the context geometry if it exists, and otherwise the index.
Okay... next stop the ID Node
The ID node gives an integer value indicating the stable random identifier of each element on the point domain, which is stored in the id attribute.
The node to set this data is the Set ID Node node.
On to the Set ID Node then...
Set ID node
The Set ID node fills the id attribute on the input geometry. If the attribute does not exist yet, it will be created with a default value of zero. The ID is also created by the Distribute Points on Faces, and it is used in the Random Value Node and other nodes if it exists.
The input node for this data is the ID Node.
From all that, what I gather is that the Random Value Node has an ID socket that is for accepting a value that drives the random number generator seed, and the ID Node also deals with this ID, and the Set ID Node can set such a value, and this is used by the Random Number Value Node... so we are right back at the beginning.
None of this documentation really explains how to use these nodes with one another, and plugging both the ID Node and the Set ID Node into the Random Value Node's ID socket have made no difference in the output. It is still red.
The fundamental question:
How are these nodes all supposed to work with one another to produce a random integer/float/etc that can actually produce a valid value that works with other nodes?