How do i control a driver using an RGB node?

Question

Lets say i got a node and i want to change the color of that node with another node using drivers

something like this, so if i have my RGB node color set to white, it changes the Diffuse node to white too, if its red it changes to red etc. the goal is to make this possible with drivers only, i tried driving the Diffuse node to be controlled by the RGB node's RNA path but it didnt really work, it seems it can only control the driver with a value node or similar but it wont work with RGB nodes or color information. how can i make this to work?

Answer 1

I was looking for this as well, but you can actually do it, just not Quite in the same way, and it's Way too much work. I'm writting a request to just open this up in nodes instead, but wanted to see if there was another way to do it.

So add the driver to the viewport display. Create an rgb node. Right click and copy the full path (you'll only use half of it)

in the drivers editor, select R diffuse color. expression is just var change input variable to single property, named var change the prop: to material and select the material (it's ok that it's the same material, so you don't need to create an extra one) For the path paste your path, but delete everything before node-tree... should look something like this: node_tree.nodes["RGB"].outputs[0].default_value[0]

Notice you'll have to add the [0] at the end. That tells it to use only the first value of RGBA. You should see the red value match now. Move on to G and change that number to [1], and so on. You can skip Alpha though, no point in matching 1.0 with 1.0 right? But up to you.

Now with all that, I'm hoping they can add viewport display options as input nodes to the material output node as an option. Because it would be a Heck of a lot easier to just connect them.

Answer 2

I thought I'd leave this here in case others follow this breadcrumb. I could find no docs or examples on this so it was made by trial and error.

Here is how I delete and remake a color driver in a world node tree RGB node using python.

I have a custom object properties named "Sky" as a color.

to define a color custom property, use this syntax in the Property Value field on a color named "Sky":

[1.0, 1.0, 1.0, 1.0]

here's the logic to then clear and rebuild the driver in python.

world_nodes = bpy.context.scene.world 
if world_nodes:
    sky_color = color_swatch_object["Sky"]
    background_node = world_nodes.node_tree.nodes.get('Background')
    colorNode = background_node.inputs[0].links[0].from_node
    if sky_color:
        try:
            colorNode.outputs[0].driver_remove("default_value")[0] 
            colorNode.outputs[0].driver_remove("default_value")[1] 
            colorNode.outputs[0].driver_remove("default_value")[2] 
        except:
            pass

        colorDriverRed = colorNode.outputs[0].driver_add("default_value")[0] 
        colorDriverGreen = colorNode.outputs[0].driver_add("default_value")[1] 
        colorDriverBlue = colorNode.outputs[0].driver_add("default_value")[2] 

        colorDriverRed.driver.type = 'SUM'
        newVar = colorDriverRed.driver.variables.new()
        newVar.name = "Sky"
        newVar.type = 'SINGLE_PROP'
        newVar.targets[0].id = color_swatch_object
        newVar.targets[0].data_path = '["Sky"][0]' 

        colorDriverGreen.driver.type = 'SUM'
        newVar = colorDriverGreen.driver.variables.new()
        newVar.name = "Sky"
        newVar.type = 'SINGLE_PROP'
        newVar.targets[0].id = color_swatch_object
        newVar.targets[0].data_path = '["Sky"][1]' 

        colorDriverBlue.driver.type = 'SUM'
        newVar = colorDriverBlue.driver.variables.new()
        newVar.name = "Sky"
        newVar.type = 'SINGLE_PROP'
        newVar.targets[0].id = color_swatch_object
        newVar.targets[0].data_path = '["Sky"][2]'