Is it possible to automatically apply materials and export model?

Question

I have around 200 materials that I want to apply to an object, one at a time, and export as glb, so I have one version of the model with every texture. Is it possible write a script that applies one material, exports as a glb file, applies the next material, exports, and so on until all the materials have been applied and exported?

Answer 1

Sure, here is pseudocode for an example script that would do that:

import bpy

object = bpy.context.active_object

materials_to_use = ['reddish', 'bluish']

for material_name in materials_to_use:
    object.material_slots[0].material = bpy.data.materials[material_name]
    bpy.ops.export_scene.gltf()

This script makes an assumption that you only have a single object that you want to change the material on and that you only care about the first material. Adjust accordingly.

The 'pseudo' part comes in figuring out materials_to_use. Above I manually listed material names. That's fine for a few materials but you have around 200 so you'll need to construct the list some other way. Or you could simply do it for every material in the blend file and then sort it out by deleting outputs. In that case

import bpy

object = bpy.context.active_object

for material in bpy.data.materials:
    object.material_slots[0].material = material
    bpy.ops.export_scene.gltf()

Oh, and I left out a step: setting the file name for export_scene to use. bpy.ops.export_scene.gltf() takes a filepath="SOME PATH argument. You need to output each material to a different path. The usual technique is to set a directory name before the loop and create a file name like material.name + '.glb' in the loop and using the combined directory + file name as the filepath argument.

Here is one way to do that with my original example

import bpy
from pathlib import Path

object = bpy.context.active_object

materials_to_use = ['reddish', 'bluish']

dir = Path("C:/tmp")

for material_name in materials_to_use:
    object.material_slots[0].material = bpy.data.materials[material_name]
    file = material_name + ".glb"
    bpy.ops.export_scene.gltf(filepath=str(dir / file))

and for every material

import bpy
from pathlib import Path

object = bpy.context.active_object
dir = Path("C:/tmp")

for material in bpy.data.materials:
    object.material_slots[0].material = material
    file = material.name + ".glb"
    bpy.ops.export_scene.gltf(filepath=str(dir / file))