diff --git a/src/c3nav/editor/api.py b/src/c3nav/editor/api.py
index 24e9a9a3..8a6dadbd 100644
--- a/src/c3nav/editor/api.py
+++ b/src/c3nav/editor/api.py
@@ -197,11 +197,12 @@ class EditorViewSet(EditorViewSetMixin, ViewSet):
 
                 space.bounds = True
 
+                # deactivated for performance reasons
                 buildings = level.buildings.all()
-                buildings_geom = cascaded_union([building.geometry for building in buildings])
-                for other_space in other_spaces:
-                    if other_space.outside:
-                        other_space.geometry = other_space.geometry.difference(buildings_geom)
+                # buildings_geom = cascaded_union([building.geometry for building in buildings])
+                # for other_space in other_spaces:
+                #     if other_space.outside:
+                #         other_space.geometry = other_space.geometry.difference(buildings_geom)
                 for other_space in chain(other_spaces, other_spaces_lower, other_spaces_upper):
                     other_space.opacity = 0.4
                     other_space.color = '#ffffff'