Can I delete all materials of all objects in a scene quickly?

Question

Is there a quick way to delete all materials in the scene? I have a scene containing 20+ materials and all linked to objects. I'd like to remove all the materials from my blender file.

Answer 1

Yes, you can. Easy way would be:

1. Select all objects, keep one active, remove all materials on it by pressing the "-" button on the right-hand side of material slot list;
2. Then, from the drop-down list (below it), choose Copy Material to Others. Save the file.

All unused material data will be removed after saving. You cannot see them anymore after reopening.

Answer 2

to delete all materials:

import bpy
for material in bpy.data.materials:
    material.user_clear()
    bpy.data.materials.remove(material)

Answer 3

There's an addon Material Utils, which ships with Blender.

Enable it in the User Preferences > Addons, select all objects A, hit Q over 3D View and chose Remove Material Slots:

It currently works on the active object only, despite the tooltip stating it would work for multiple objects. Here's a scripted solution for all selected, editable (non-linked) objects:

import bpy

for ob in bpy.context.selected_editable_objects:
    ob.active_material_index = 0
    for i in range(len(ob.material_slots)):
        bpy.ops.object.material_slot_remove({'object': ob})

Answer 4

Here is an updated version of reflog's answer. This removes all materials programatically.

for material in bpy.data.materials:
        bpy.data.materials.remove(material, do_unlink=True)

I was getting errors when using material.user_clear(), and read that it's something that shouldn't be done anymore. The above works flawlessly in the current version of Blender (3.0.0 at the time of writing).

Answer 5

just had to solve this problem too. The other answers here didnt work for me. My solution:

1. Select all of the objects you want to remove materials from.
2. In Object Mode, Join them (menu: Object/Join or shortcut: ctrl + 'j').
3. Remove the material(s) in the materials panel by pressing the '-' button.
4. In Edit Mode, select all ('a'), press 'p' and separate (by loose parts in my case) to get your individual objects back.