glTF exporter: fix exporing instances when apply modifier is disabled

io_scene_gltf2/__init__.py

@@ -15,7 +15,7 @@
 bl_info = {
     'name': 'glTF 2.0 format',
     'author': 'Julien Duroure, Norbert Nopper, Urs Hanselmann, Moritz Becher, Benjamin Schmithüsen, Jim Eckerlein, and many external contributors',
-    "version": (1, 1, 12),
+    "version": (1, 1, 13),
     'blender': (2, 81, 6),
     'location': 'File > Import-Export',
     'description': 'Import-Export as glTF 2.0',

io_scene_gltf2/blender/exp/gltf2_blender_gather_nodes.py

@@ -283,6 +283,15 @@ def __gather_mesh(blender_object, export_settings):
     else:
         blender_mesh = blender_object.data
         skip_filter = False
+        # If no skin are exported, no need to have vertex group, this will create a cache miss
+        if not export_settings[gltf2_blender_export_keys.SKINS]:
+            vertex_groups = None
+            modifiers = None
+        else:
+            # Check if there is an armature modidier
+            if len([mod for mod in blender_object.modifiers if mod.type == "ARMATURE"]) == 0:
+                vertex_groups = None # Not needed if no armature, avoid a cache miss
+                modifiers = None
 
     material_names = tuple([ms.material.name for ms in blender_object.material_slots if ms.material is not None])