okay the docs you gave were great for insight
working code to change parameter of roughness for x given mat selections
import c4d import maxon from maxon import GraphDescription doc = c4d.documents.GetActiveDocument() # Get selected materials directly selected_materials = doc.GetActiveMaterials() # Modify roughness for each selected material for material in selected_materials: graph = GraphDescription.GetGraph(material, nodeSpaceId=maxon.NodeSpaceIdentifiers.RedshiftMaterial) GraphDescription.ApplyDescription(graph, { "$query": { "$type": "Standard Material" }, "Reflection/Roughness": 1 }) c4d.EventAdd()