I don't know how much to impose on folks here, but I'll give it a try. I'm using Poser 12.

I have a bunch of props/actors whose names begin with Building (ex: Building12_2)

Some of these actors have material names that begin with Concrete (either Concrete1, Concrete2, or Concrete3).

Some of these materials contain a Clouds node.

I want to change the Gain on these nodes from 1.0 to .75

I know this is simple for Python coders, but I ain't one of them. I got as far as this:

# initial references
scene = poser.Scene()
actor = scene.Actor('ActorName')

# loop actors in scene, with specific names...
for actor in scene.Actors():
    if actor.Name().startswith('Building'):
        # ...do something

And I found this off the pydoc.browse (1521) python shell.
kNodeTypeCodeCLOUDS = 'clouds'

Can I get an Amen? I mean Script. Thanks.

scene = poser.Scene()
for actor in [a for a in scene.Actors() if a.Name().startswith("Building")]:  # type: poser.ActorType
    for tree in [m.ShaderTree() for m in actor.Materials() if m.Name().startswith("Concret")]:  # type: poser.ShaderTreeType
        for node in [n for n in tree.Nodes() if n.Type() == poser.kNodeTypeCodeCLOUDS]:  # type: poser.ShaderNodeType
            node.InputByInternalName("Gain").SetFloat(0.75)
print("Done.")

adp001 posted at 1:34 PM Wed, 11 January 2023 - #4453662

scene = poser.Scene()
for actor in [a for a in scene.Actors() if a.Name().startswith("Building")]:  # type: poser.ActorType
    for tree in [m.ShaderTree() for m in actor.Materials() if m.Name().startswith("Concret")]:  # type: poser.ShaderTreeType
        for node in [n for n in tree.Nodes() if n.Type() == poser.kNodeTypeCodeCLOUDS]:  # type: poser.ShaderNodeType
            node.InputByInternalName("Gain").SetFloat(0.75)
print("Done.")

on Edit: BTW, it worked like a charm and in the blink of an eye!

Glad that it helped.