Building storeys now show a derived storey height so you don't need to do math

src/blenderbim/blenderbim/bim/import_ifc.py

@@ -286,7 +286,6 @@ class IfcImporter:
         if self.non_body_contexts:
             self.settings_2d.set_context_ids(self.non_body_contexts)
 
-
     def process_element_filter(self):
         if self.ifc_import_settings.has_filter:
             self.elements = set(self.ifc_import_settings.elements)

src/blenderbim/blenderbim/bim/module/geometry/data.py

@@ -0,0 +1,61 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import bpy
+import blenderbim.tool as tool
+import ifcopenshell.util.placement
+
+
+def refresh():
+    DerivedPlacementsData.is_loaded = False
+
+
+class DerivedPlacementsData:
+    data = {}
+    is_loaded = False
+
+    @classmethod
+    def load(cls):
+        cls.data = {
+            "is_storey": cls.is_storey(),
+            "storey_height": cls.get_storey_height(),
+        }
+        cls.is_loaded = True
+
+    @classmethod
+    def is_storey(cls):
+        element = tool.Ifc.get_entity(bpy.context.active_object)
+        if element:
+            return element.is_a("IfcBuildingStorey")
+
+    @classmethod
+    def get_storey_height(cls):
+        if not cls.is_storey():
+            return
+        element = tool.Ifc.get_entity(bpy.context.active_object)
+        storeys = [
+            (s, ifcopenshell.util.placement.get_local_placement(s.ObjectPlacement)[2][3])
+            for s in tool.Ifc.get().by_type("IfcBuildingStorey")
+        ]
+        storeys = sorted(storeys, key=lambda s: s[1])
+        for i, storey in enumerate(storeys):
+            if storey[0] != element:
+                continue
+            if i >= len(storeys):
+                return "N/A"
+            return "{0:.3f}".format(round(storeys[i + 1][1] - storey[1], 3))

src/blenderbim/blenderbim/bim/module/geometry/ui.py

@@ -20,6 +20,7 @@ import bpy
 from bpy.types import Panel
 from ifcopenshell.api.geometry.data import Data
 from blenderbim.bim.ifc import IfcStore
+from blenderbim.bim.module.geometry.data import DerivedPlacementsData
 
 
 class BIM_PT_representations(Panel):
@@ -153,6 +154,9 @@ class BIM_PT_derived_placements(Panel):
     bl_parent_id = "OBJECT_PT_transform"
 
     def draw(self, context):
+        if not DerivedPlacementsData.is_loaded:
+            DerivedPlacementsData.load()
+
         z = context.active_object.matrix_world.translation.z
         z_values = [co[2] for co in context.active_object.bound_box]
         row = self.layout.row(align=True)
@@ -172,6 +176,11 @@ class BIM_PT_derived_placements(Panel):
             row.label(text="Max Local Z")
             row.label(text="{0:.3f}".format(max(z_values) + z - collection_z))
 
+        if DerivedPlacementsData.data["is_storey"]:
+            row = self.layout.row(align=True)
+            row.label(text="Storey Height")
+            row.label(text=DerivedPlacementsData.data["storey_height"])
+
 
 class BIM_PT_workarounds(Panel):
     bl_label = "IFC Vendor Workarounds"

src/blenderbim/blenderbim/bim/module/project/__init__.py

@@ -53,6 +53,7 @@ classes = (
     ui.BIM_UL_links,
 )
 
+
 def menu_func_export(self, context):
     self.layout.operator(operator.ExportIFC.bl_idname, text="Industry Foundation Classes (.ifc/.ifczip/.ifcjson)")