Remove Duplicate Materials

The following code will remove duplicate materials from your project. For example, if you have steel_metal and steel_metal.001, it'll turn all of them into steel_metal and delete the duplicate .001, .002, etc. materials.

import bpy
import re

def get_base_material_name(name):
    """Returns the base name of a material by stripping .001, .002, etc."""
    return re.sub(r"\.\d{3}$", "", name)

def deduplicate_materials_and_cleanup():
    # Track base materials
    base_materials = {}

    # Map of duplicate materials to their base
    duplicate_map = {}

    # First pass: build a map of base materials
    for mat in bpy.data.materials:
        base_name = get_base_material_name(mat.name)
        if base_name not in base_materials:
            base_materials[base_name] = mat
        else:
            # Avoid replacing base with another of the same name
            if mat != base_materials[base_name]:
                duplicate_map[mat] = base_materials[base_name]

    # Second pass: replace duplicates on objects
    for obj in bpy.data.objects:
        if obj.type == 'MESH':
            for i, slot in enumerate(obj.material_slots):
                mat = slot.material
                if mat in duplicate_map:
                    print(f"Replacing '{mat.name}' with '{duplicate_map[mat].name}' on '{obj.name}'")
                    slot.material = duplicate_map[mat]

    # Third pass: remove unused duplicates
    for dup_mat, base_mat in duplicate_map.items():
        if dup_mat.users == 0:
            print(f"Removing unused duplicate material '{dup_mat.name}'")
            bpy.data.materials.remove(dup_mat)

    print("Material deduplication and cleanup complete!")

# Run it
deduplicate_materials_and_cleanup()