You can now add cost items into a cost schedule, and as sub items to a parent cost item. Thanks myoualid and Jesusbill!

src/ifcopenshell-python/ifcopenshell/api/cost/data.py

@@ -4,15 +4,19 @@ import ifcopenshell.util.date
 class Data:
     is_loaded = False
     cost_schedules = {}
+    cost_items = {}
 
     @classmethod
     def purge(cls):
         cls.is_loaded = False
         cls.cost_schedules = {}
+        cls.cost_items = {}
 
     @classmethod
     def load(cls, file):
         cls.cost_schedules = {}
+        cls.cost_items = {}
+
         for cost_schedule in file.by_type("IfcCostSchedule"):
             data = cost_schedule.get_info()
             del data["OwnerHistory"]
@@ -20,5 +24,21 @@ class Data:
                 data["SubmittedOn"] = ifcopenshell.util.date.ifc2datetime(data["SubmittedOn"])
             if data["UpdateDate"]:
                 data["UpdateDate"] = ifcopenshell.util.date.ifc2datetime(data["UpdateDate"])
+            data["RelatedObjects"] = []
+            for rel in cost_schedule.Controls:
+                for related_object in rel.RelatedObjects:
+                    if related_object.is_a("IfcCostItem"):
+                        data["RelatedObjects"].append(related_object.id())
+                        break # We are only allowed one summary cost item
             cls.cost_schedules[cost_schedule.id()] = data
+
+        for cost_item in file.by_type("IfcCostItem"):
+            data = cost_item.get_info()
+            del data["OwnerHistory"]
+            del data["CostValues"]
+            del data["CostQuantities"]
+            data["RelatedObjects"] = []
+            for rel in cost_item.IsNestedBy:
+                [data["RelatedObjects"].append(o.id()) for o in rel.RelatedObjects if o.is_a("IfcCostItem")]
+            cls.cost_items[cost_item.id()] = data
         cls.is_loaded=True