Ошибка при выгрузке в GLTF из 2.79? что может быть не так?

Файлы GLTF не создаются

Сообщение ошибки:

Traceback (most recent call last):
  File "C:\Users\user1\AppData\Roaming\Blender Foundation\Blender\2.79\scripts\addons\verge3d\__init__.py", line 148, in execute
    return gltf2_export.save(self, context, exportSettings)
  File "C:\Users\user1\AppData\Roaming\Blender Foundation\Blender\2.79\scripts\addons\verge3d\gltf2_export.py", line 120, in save
    generateGLTF(operator, context, exportSettings, glTF)
  File "C:\Users\user1\AppData\Roaming\Blender Foundation\Blender\2.79\scripts\addons\verge3d\gltf2_generate.py", line 3343, in generateGLTF
    generateMeshes(operator, context, exportSettings, glTF)
  File "C:\Users\user1\AppData\Roaming\Blender Foundation\Blender\2.79\scripts\addons\verge3d\gltf2_generate.py", line 1489, in generateMeshes
    primitive['material'] = get_or_create_default_material_index(glTF)
  File "C:\Users\user1\AppData\Roaming\Blender Foundation\Blender\2.79\scripts\addons\verge3d\gltf2_get.py", line 646, in get_or_create_default_material_index
    def_idx = gltf.getMaterialIndex(glTF, DEFAULT_MAT_NAME)
NameError: name 'gltf' is not defined