Optimise object placement change checking, so medium sized project exports are 5 seconds faster at minimum, but can be much higher since false positives are culled.

src/blenderbim/blenderbim/tool/geometry.py

@@ -18,6 +18,7 @@
 
 import bpy
 import logging
+import numpy as np
 import ifcopenshell
 import blenderbim.core.tool
 import blenderbim.core.style
@@ -223,6 +224,12 @@ class Geometry(blenderbim.core.tool.Geometry):
     def link(cls, element, obj):
         obj.BIMMeshProperties.ifc_definition_id = element.id()
 
+    @classmethod
+    def record_object_position(cls, obj):
+        # These are recorded separately because they have different numerical tolerances
+        obj.BIMObjectProperties.location_checksum = repr(np.array(obj.matrix_world.translation).tobytes())
+        obj.BIMObjectProperties.rotation_checksum = repr(np.array(obj.matrix_world.to_3x3()).tobytes())
+
     @classmethod
     def rename_object(cls, obj, name):
         obj.name = name