Fix issue with calculated params in stair ui

it was displaying incorrect data when stair was just loaded because it was relying on BIMStairProperties in ui.py

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

@@ -314,6 +314,7 @@ class StairData:
         if not cls.data["pset_data"]:
             return
         cls.data["general_params"] = cls.general_params()
+        cls.data["calculated_params"] = cls.calculated_params()
 
     @classmethod
     def pset_data(cls):
@@ -330,6 +331,28 @@ class StairData:
             general_params[prop_readable_name] = prop_value
         return general_params
 
+    @classmethod
+    def calculated_params(cls):
+        props = bpy.context.active_object.BIMStairProperties
+
+        if props.is_editing:
+            si_conversion = ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
+            number_of_treads = props.number_of_treads
+            height = props.height / si_conversion
+            tread_run = props.tread_run / si_conversion
+        else:
+            data = cls.data["pset_data"]["data_dict"]
+            number_of_treads = data["number_of_treads"]
+            height = data["height"]
+            tread_run = data["tread_run"]
+
+        calculated_params = {}
+        number_of_rises = number_of_treads + 1
+        calculated_params["Number of risers"] = number_of_rises
+        calculated_params["Tread rise"] = round(height / number_of_rises, 5)
+        calculated_params["Length"] = round(tread_run * number_of_rises, 5)
+        return calculated_params
+
 
 class SverchokData:
     data = {}

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

@@ -278,16 +278,10 @@ class BIM_PT_stair(bpy.types.Panel):
                     row.label(text=str(prop_value))
 
             # calculated properties
-            number_of_rises = props.number_of_treads + 1
-            row = self.layout.row(align=True)
-            row.label(text="Number of risers")
-            row.label(text=str(number_of_rises))
-            row = self.layout.row(align=True)
-            row.label(text="Tread rise")
-            row.label(text=str(round(props.height / number_of_rises, 5)))
-            row = self.layout.row(align=True)
-            row.label(text="Length")
-            row.label(text=str(round(props.tread_run * number_of_rises, 5)))
+            for prop_name, prop_value in StairData.data["calculated_params"].items():
+                row = self.layout.row(align=True)
+                row.label(text=prop_name)
+                row.label(text=str(prop_value))
         else:
             row = self.layout.row()
             row.label(text="No Stair Found")