From d55a2915898b06b6b4fdcc5106db8de015e5be89 Mon Sep 17 00:00:00 2001
From: Andrej730 <azhilenkov@gmail.com>
Date: Fri, 27 Dec 2024 18:20:53 +0500
Subject: [PATCH] get_top_area to calculate area for the roof #5899

---
 src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json         | 4 ++--
 src/ifc5d/ifc5d/qto.py                             | 5 +++++
 src/ifcopenshell-python/ifcopenshell/util/shape.py | 4 ++++
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json b/src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json
index 64b69884ec..dfe870bbe2 100644
--- a/src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json
+++ b/src/ifc5d/ifc5d/IFC4QtoBaseQuantities.json
@@ -484,8 +484,8 @@
             },
             "IfcRoof": {
                 "Qto_RoofBaseQuantities": {
-                    "GrossArea": null,
-                    "NetArea": null,
+                    "GrossArea": "gross_get_top_area",
+                    "NetArea": "net_get_top_area",
                     "ProjectedArea": null
                 }
             },
diff --git a/src/ifc5d/ifc5d/qto.py b/src/ifc5d/ifc5d/qto.py
index c9681e356f..eefa182054 100644
--- a/src/ifc5d/ifc5d/qto.py
+++ b/src/ifc5d/ifc5d/qto.py
@@ -145,6 +145,11 @@ class IfcOpenShell:
             "Side area",
             "The side (non-projected) are of the shape as seen from the local Y-axis",
         ),
+        "get_top_area": Function(
+            "IfcAreaMeasure",
+            "Top area",
+            "The total surface area deviating by no more than 45 degrees from the local Z+ axis.",
+        ),
         # IfcVolumeMeasure
         "get_volume": Function("IfcVolumeMeasure", "Volume", "Calculates the volume of a manifold shape"),
     }
diff --git a/src/ifcopenshell-python/ifcopenshell/util/shape.py b/src/ifcopenshell-python/ifcopenshell/util/shape.py
index 71e9db1614..c99f479000 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/shape.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/shape.py
@@ -532,6 +532,10 @@ def get_max_side_area(geometry: ShapeType) -> float:
     return max(get_side_area(geometry, axis="X"), get_side_area(geometry, axis="Y"), get_side_area(geometry, axis="Z"))
 
 
+def get_top_area(geometry: ShapeType) -> float:
+    return get_side_area(geometry, axis="Z", angle=45)
+
+
 def get_footprint_area(
     geometry: ShapeType,
     axis: AXIS_LITERAL = "Z",