diff --git a/src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json b/src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json
index aa3a80b632..c002cfaa4c 100644
--- a/src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json
+++ b/src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json
@@ -529,16 +529,16 @@
                 "Qto_SpaceBaseQuantities": {
                     "FinishCeilingHeight": null,
                     "FinishFloorHeight": null,
-                    "GrossCeilingArea": null,
-                    "GrossFloorArea": null,
-                    "GrossPerimeter": null,
-                    "GrossVolume": null,
+                    "GrossCeilingArea": "gross_get_top_area",
+                    "GrossFloorArea": "gross_get_footprint_area",
+                    "GrossPerimeter": "gross_get_footprint_perimeter",
+                    "GrossVolume": "gross_get_volume",
                     "GrossWallArea": null,
-                    "Height": null,
-                    "NetCeilingArea": null,
-                    "NetFloorArea": null,
+                    "Height": "net_get_z",
+                    "NetCeilingArea": "net_get_top_area",
+                    "NetFloorArea": "net_get_footprint_area",
                     "NetPerimeter": null,
-                    "NetVolume": null,
+                    "NetVolume": "net_get_volume",
                     "NetWallArea": null
                 }
             },
diff --git a/src/ifc5d/ifc5d/IFC4X3QtoBaseQuantities.json b/src/ifc5d/ifc5d/IFC4X3QtoBaseQuantities.json
index 2f1a56ffac..017e164119 100644
--- a/src/ifc5d/ifc5d/IFC4X3QtoBaseQuantities.json
+++ b/src/ifc5d/ifc5d/IFC4X3QtoBaseQuantities.json
@@ -665,16 +665,16 @@
                 "Qto_SpaceBaseQuantities": {
                     "FinishCeilingHeight": null,
                     "FinishFloorHeight": null,
-                    "GrossCeilingArea": null,
-                    "GrossFloorArea": null,
-                    "GrossPerimeter": null,
-                    "GrossVolume": null,
+                    "GrossCeilingArea": "gross_get_top_area",
+                    "GrossFloorArea": "gross_get_footprint_area",
+                    "GrossPerimeter": "gross_get_footprint_perimeter",
+                    "GrossVolume": "gross_get_volume",
                     "GrossWallArea": null,
-                    "Height": null,
-                    "NetCeilingArea": null,
-                    "NetFloorArea": null,
+                    "Height": "net_get_z",
+                    "NetCeilingArea": "net_get_top_area",
+                    "NetFloorArea": "net_get_footprint_area",
                     "NetPerimeter": null,
-                    "NetVolume": null,
+                    "NetVolume": "net_get_volume",
                     "NetWallArea": null
                 }
             },