Blender now helps prevent saving Blender without having an exported IFC. See #1323.

src/ifcblenderexport/blenderbim/bim/__init__.py

@@ -165,6 +165,7 @@ if bpy is not None:
         bpy.app.handlers.depsgraph_update_post.append(on_register)
         bpy.app.handlers.load_post.append(handler.setDefaultProperties)
         bpy.app.handlers.load_post.append(handler.loadIfcStore)
+        bpy.app.handlers.save_pre.append(handler.ensureIfcExported)
         bpy.app.handlers.save_pre.append(handler.storeIdMap)
         bpy.types.TOPBAR_MT_file_export.append(menu_func_export)
         bpy.types.TOPBAR_MT_file_import.append(menu_func_import)
@@ -191,6 +192,7 @@ if bpy is not None:
         bpy.app.handlers.load_post.remove(handler.setDefaultProperties)
         bpy.app.handlers.load_post.remove(handler.loadIfcStore)
         bpy.app.handlers.save_pre.remove(handler.storeIdMap)
+        bpy.app.handlers.save_pre.remove(handler.ensureIfcExported)
         bpy.types.TOPBAR_MT_file_export.remove(menu_func_export)
         bpy.types.TOPBAR_MT_file_import.remove(menu_func_import)
         del bpy.types.Scene.BIMProperties

src/ifcblenderexport/blenderbim/bim/handler.py

@@ -10,22 +10,34 @@ def loadIfcStore(scene):
     IfcStore.file = None
     IfcStore.schema = None
     props = bpy.context.scene.BIMProperties
-    IfcStore.id_map = {int(k): bpy.data.objects.get(v) for k, v in json.loads(props.id_map).items()} if props.id_map else {}
+    IfcStore.id_map = (
+        {int(k): bpy.data.objects.get(v) for k, v in json.loads(props.id_map).items()} if props.id_map else {}
+    )
     IfcStore.guid_map = (
         {k: bpy.data.objects.get(v) for k, v in json.loads(props.guid_map).items()} if props.id_map else {}
     )
 
     # Purge data cache
     from blenderbim.bim import modules
+
     for module in modules.values():
         if not module:
             continue
         try:
-            getattr(getattr(module, 'data'), 'Data').purge()
+            getattr(getattr(module, "data"), "Data").purge()
         except AttributeError:
             pass
 
 
+@persistent
+def ensureIfcExported(scene):
+    print('ensuring')
+    if IfcStore.get_file() and not bpy.context.scene.BIMProperties.ifc_file:
+        # The invocation pops up a file select window.
+        # This is non-blocking, therefore the Blend file is saved before we export.
+        bpy.ops.export_ifc.bim("INVOKE_DEFAULT", should_force_resave=True)
+
+
 @persistent
 def storeIdMap(scene):
     bpy.context.scene.BIMProperties.id_map = json.dumps({k: v.name for k, v in IfcStore.id_map.items()})

src/ifcblenderexport/blenderbim/bim/operator.py

@@ -67,6 +67,7 @@ class ExportIFC(bpy.types.Operator):
     filepath: bpy.props.StringProperty(subtype="FILE_PATH")
     json_version: bpy.props.EnumProperty(items=[("4", "4", ""), ("5a", "5a", "")], name="IFC JSON Version")
     json_compact: bpy.props.BoolProperty(name="Export Compact IFCJSON", default=False)
+    should_force_resave: bpy.props.BoolProperty(name="Resave .blend", default=False)
 
     def invoke(self, context, event):
         if not self.filepath:
@@ -103,6 +104,8 @@ class ExportIFC(bpy.types.Operator):
             new.name = output_file
         if not bpy.context.scene.BIMProperties.ifc_file:
             bpy.context.scene.BIMProperties.ifc_file = output_file
+        if self.should_force_resave:
+            bpy.ops.wm.save_as_mainfile(filepath=bpy.data.filepath)
         return {"FINISHED"}