i have a Material called "Dust" that has 4 nodes. I now need a script that copies all nodes and paste it to all materials of objects in all activated collections.
Then the Output of the Map Range Node shall be connected to the Roughness Input of the Sheen Tab on the materials like in this example. Also the Weight shall be set to 0.25 and the Tint Color Value to 0.5 for every material where the nodes are copied.
Is that somehow possible? I really need it and would appreciate any help!!
Here is a little script I wrote to add a node group to many materials. The script ...
If you want to modify only objects that are in a certain collection you need to change line 5 to fill the objects set (How to list all collections and their objects?). Note, that checking if a collection is active/enabled in the outliner is a bit more complicated because the View Layer controls this (see How can I check which of my collections are hidden in viewport?). So I kept it simple.
Don't forget to make a backup before you run the script. In the system console (main menu Window > Toggle System Console), you can check what the script is doing. Ctrl+C in the system console window will stop it.
import bpy
from mathutils import Vector
'list' (set) of objects to check
objects = set(obj for obj in bpy.data.objects)
keep track of the materials done
materials_done = set()
def material_uses_group(material, node_group_to_check) -> bool:
for node in material.node_tree.nodes:
# check whether the node is a node group and has the same name as the group to be added.
# Note: node.name is an internal name (e.g. 'Group') as shown in the side panel.
# It's not the name of the node as shown on the node, it's node.node_tree.name
# (e.g. 'Dust'). It can be overwritten by node.label.
# Only groups have node.node_tree attribute, can be checked with hasattr()
if node.bl_idname == 'ShaderNodeGroup':
#print(f"DEBUG: node.bl_idname = {node.bl_idname}, node.node_tree.name = {node.node_tree.name}, node_group.name = {node_group_to_check.name}")
if hasattr(node, 'node_tree') and node.node_tree.name == node_group_to_check.name:
return True
return False
def add_node_group_to_material(material, node_group_to_add) -> bool:
# find the Principled BSDF
print(f" - looking for Principled BSDF node in material {material.name}")
pbsdf = None
for node in material.node_tree.nodes:
if node.bl_idname == 'ShaderNodeBsdfPrincipled':
pbsdf = node
break
# add node group if found
if pbsdf != None:
print(f" + found it, adding group to material {material.name}")
new_group = material.node_tree.nodes.new('ShaderNodeGroup')
new_group.node_tree = node_group_to_add
new_group.location = pbsdf.location - Vector([240, 200]) # <----- position, left of the P.BSDF
# linking and values
material.node_tree.links.new(pbsdf.inputs['Sheen Roughness'], new_group.outputs[0])
pbsdf.inputs['Sheen Weight'].default_value = 0.250 # <------- value
pbsdf.inputs['Sheen Tint'].default_value = [0.5, 0.5, 0.5, 1.0] # <---- RGBA
return True
else:
print(f" - no Principled BSDF node found in material {material.name}, ignored")
return False
def main() -> int:
# actually, this is a node tree (my_node_group.bl_idname == 'ShaderNodeTree').
# The group used in the material is 'ShaderNodeGroup'.
my_node_group = bpy.data.node_groups['Dust'] # <---- the node group to add to the materials
# main loop
for obj in objects:
if obj.type != 'MESH':
print(f"Skipping object {obj.name} (type {obj.type})")
continue
print(f"Checking materials of {obj.name} ")
# check material slots
for idx, slot in enumerate(obj.material_slots):
if slot.material is None:
print(f"- WARN: found no material {obj.name}, empty slot #{idx}, skip")
continue
if slot.material.name in materials_done: # already done?
print(f"- found again material {slot.material.name} in slot #{idx}, skip")
continue
if not slot.material.use_nodes:
print(f"- found material {slot.material.name} in slot #{idx} but it does not use nodes, skip")
continue
print(f"+ found material {slot.material.name} in slot #{idx}, trying to add node group")
if material_uses_group(slot.material, my_node_group):
print(f" - no, node group is already in material, skip")
materials_done.add(slot.material.name)
continue
if add_node_group_to_material(slot.material, my_node_group):
print(" OK, node group added")
materials_done.add(slot.material.name)
if name == "main":
main()
print("-- DONE --")
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