Merge pull request #2420 from KhronosGroup/fix_2919

Fix #2419 - Fix crash when animation on not used material

addons/io_scene_gltf2/blender/imp/animation.py

@@ -54,6 +54,9 @@ def anim(gltf, anim_idx):
                     BlenderPointerAnim.anim(gltf, anim_idx, light, light_idx, 'LIGHT')
 
             for mat_idx, mat in enumerate(gltf.data.materials if gltf.data.materials else []):
+                if len(mat.blender_material) == 0:
+                    # The animated material is not used in Blender, so do not animate it
+                    continue
                 if len(mat.animations) != 0:
                     BlenderPointerAnim.anim(gltf, anim_idx, mat, mat_idx, 'MATERIAL')
                 if mat.normal_texture is not None and len(mat.normal_texture.animations) != 0:
@@ -167,5 +170,8 @@ def restore_animation(gltf, animation_name):
                     restore_animation_on_object(light['blender_object_data'], animation_name)
 
             for mat in gltf.data.materials if gltf.data.materials else []:
+                if len(mat.blender_material) == 0:
+                    # The animated material is not used in Blender, so do not animate it
+                    continue
                 restore_animation_on_object(mat.blender_nodetree, animation_name)
                 restore_animation_on_object(mat.blender_mat, animation_name)