Added default NONE game for in the scene tab, and a comprehensive error when...

Added default NONE game for in the scene tab, and a comprehensive error when they forget to set the game.

io_scene_niftools/nif_export.py

@@ -88,6 +88,11 @@ class NifExport(NifCommon):
 
         try:  # catch export errors
 
+            # protect against null nif versions
+            if bpy.context.scene.niftools_scene.game == 'NONE':
+                raise NifError("You have not selected a game. Please select a game and"
+                                " nif version in the scene tab.")
+
             # find all objects that do not have a parent
             self.exportable_objects, self.root_objects = self.objecthelper.get_export_objects()
             if not self.exportable_objects:

io_scene_niftools/properties/scene.py

@@ -84,14 +84,14 @@ class Scene(PropertyGroup):
 
     # For which game to export.
     game: bpy.props.EnumProperty(
-        items=[
+        items=[('NONE', 'NONE', 'No game selected')] + [
             (_game_to_enum(game), game, "Export for " + game)
             for game in sorted(
                 [x for x in NifFormat.games.keys() if x != '?'])
         ],
         name="Game",
         description="For which game to export.",
-        default='OBLIVION',
+        default='NONE',
         update=update_version_from_game)
 
     # Map game enum to nif version.