Removing all material slots in one go

Question

I need some help in removing all material slots in one go using a python script. I am able to use this, would prefer to ave all removed.

bpy.context.object.active_material_index = 0
bpy.ops.object.material_slot_remove()
bpy.context.object.active_material_index = 1
bpy.ops.object.material_slot_remove()
bpy.context.object.active_material_index = 2
bpy.ops.object.material_slot_remove()

Answer 1

You can also remove all material slots without calling the operator at all, so you don't have to bother with indexes:

bpy.context.object.data.materials.clear()

In general, I would always try to avoid calling operators unless they do something very specific that is difficult to achieve via calling usual API functions.

Answer 2

You can set the index of the list to 0, iterate through all slots and override the context of material_slot_remove().

Blender 3.2+

import bpy
from bpy import context

for obj in context.selected_editable_objects:
    obj.active_material_index = 0
    for i in range(len(obj.material_slots)):
        with context.temp_override(object=obj):
            bpy.ops.object.material_slot_remove()

Blender 2.8+

import bpy

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

Answer 3

import bpy #import the blender python library
for x in bpy.context.object.material_slots: #For all of the materials in the selected object:
    bpy.context.object.active_material_index = 0 #select the top material
    bpy.ops.object.material_slot_remove() #delete it