From fd19b2d730b8ada6280019a3750efd791ff55d4c Mon Sep 17 00:00:00 2001
From: Dion Moult <dion@thinkmoult.com>
Date: Sat, 20 Feb 2021 10:26:58 +1100
Subject: [PATCH] Fix #1312. Allow null ownership histories in IFC4.

---
 src/ifcblenderexport/blenderbim/bim/module/owner/api.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/ifcblenderexport/blenderbim/bim/module/owner/api.py b/src/ifcblenderexport/blenderbim/bim/module/owner/api.py
index 85bd8dc07f..b95d928b46 100644
--- a/src/ifcblenderexport/blenderbim/bim/module/owner/api.py
+++ b/src/ifcblenderexport/blenderbim/bim/module/owner/api.py
@@ -27,6 +27,15 @@ def update_owner_history(element, change_action=None):
 
 def create_owner_history(change_action=None):
     file = IfcStore.get_file()
+
+    if (
+        not bpy.context.scene.BIMOwnerProperties.user_person
+        or not bpy.context.scene.BIMOwnerProperties.user_organisation
+    ):
+        if file.schema == "IFC2X3":
+            assert False, "A person and organisation is required in IFC2X3."
+        return None
+
     return create_owner_history_usecase.Usecase(
         file,
         {