Derive start and finish dates and elapsed durations where possible in the task tree

src/blenderbim/blenderbim/bim/module/sequence/operator.py

@@ -307,12 +307,43 @@ class LoadTaskProperties(bpy.types.Operator):
                     isodate.duration_isoformat(task_time["ScheduleDuration"]) if task_time["ScheduleDuration"] else "-"
                 )
             else:
+                derived_start = self.derive_start(item.ifc_definition_id)
+                derived_finish = self.derive_finish(item.ifc_definition_id)
+                item.derived_start = self.canonicalise_time(derived_start) if derived_start else ""
+                item.derived_finish = self.canonicalise_time(derived_finish) if derived_finish else ""
+                if derived_start and derived_finish:
+                    derived_duration = ifcopenshell.util.date.timedelta2duration(derived_finish - derived_start)
+                    item.derived_duration = isodate.duration_isoformat(derived_duration)
                 item.start = "-"
                 item.finish = "-"
                 item.duration = "-"
         self.props.is_task_update_enabled = True
         return {"FINISHED"}
 
+    def derive_start(self, ifc_definition_id, start=None):
+        task = Data.tasks[ifc_definition_id]
+        if task["TaskTime"]:
+            schedule_start = Data.task_times[task["TaskTime"]]["ScheduleStart"]
+            if schedule_start:
+                return schedule_start
+        for subtask in task["RelatedObjects"]:
+            schedule_start = self.derive_start(subtask, start)
+            if schedule_start and (start is None or schedule_start < start):
+                start = schedule_start
+        return start
+
+    def derive_finish(self, ifc_definition_id, finish=None):
+        task = Data.tasks[ifc_definition_id]
+        if task["TaskTime"]:
+            schedule_finish = Data.task_times[task["TaskTime"]]["ScheduleFinish"]
+            if schedule_finish:
+                return schedule_finish
+        for subtask in task["RelatedObjects"]:
+            schedule_finish = self.derive_finish(subtask, finish)
+            if schedule_finish and (finish is None or schedule_finish > finish):
+                finish = schedule_finish
+        return finish
+
     def canonicalise_time(self, time):
         if not time:
             return "-"
@@ -850,7 +881,7 @@ class ImportP6(bpy.types.Operator, ImportHelper):
         p62ifc = P62Ifc()
         p62ifc.xml = self.filepath
         p62ifc.file = self.file
-        p62ifc.work_plan = self.file.by_type("IfcWorkPlan")[0]
+        p62ifc.work_plan = self.file.by_type("IfcWorkPlan")[0] if self.file.by_type("IfcWorkPlan") else None
         p62ifc.execute()
         Data.load(IfcStore.get_file())
         print("Import finished in {:.2f} seconds".format(time.time() - start))
@@ -1284,7 +1315,9 @@ class UnassignLagTime(bpy.types.Operator):
 
     def execute(self, context):
         self.file = IfcStore.get_file()
-        ifcopenshell.api.run("sequence.unassign_lag_time", self.file, **{"rel_sequence": self.file.by_id(self.sequence)})
+        ifcopenshell.api.run(
+            "sequence.unassign_lag_time", self.file, **{"rel_sequence": self.file.by_id(self.sequence)}
+        )
         Data.load(IfcStore.get_file())
         return {"FINISHED"}
 
@@ -1296,12 +1329,15 @@ class AssignLagTime(bpy.types.Operator):
 
     def execute(self, context):
         self.file = IfcStore.get_file()
-        ifcopenshell.api.run("sequence.assign_lag_time", self.file, **{"rel_sequence": self.file.by_id(self.sequence), "lag_value": "P0D"})
+        ifcopenshell.api.run(
+            "sequence.assign_lag_time",
+            self.file,
+            **{"rel_sequence": self.file.by_id(self.sequence), "lag_value": "P0D"},
+        )
         Data.load(IfcStore.get_file())
         return {"FINISHED"}
 
 
-
 class EditSequenceAttributes(bpy.types.Operator):
     bl_idname = "bim.edit_sequence_attributes"
     bl_label = "Edit Sequence"
@@ -1357,7 +1393,6 @@ class EditSequenceTimeLag(bpy.types.Operator):
         return {"FINISHED"}
 
 
-
 class DisableEditingSequence(bpy.types.Operator):
     bl_idname = "bim.disable_editing_sequence"
     bl_label = "Disable Editing Sequence Attributes"

src/blenderbim/blenderbim/bim/module/sequence/prop.py

@@ -128,6 +128,9 @@ class Task(PropertyGroup):
     duration: StringProperty(name="Duration")
     start: StringProperty(name="Start", update=updateTaskTimeStart)
     finish: StringProperty(name="Finish", update=updateTaskTimeFinish)
+    derived_start: StringProperty(name="Derived Start")
+    derived_finish: StringProperty(name="Derived Finish")
+    derived_duration: StringProperty(name="Derived Duration")
     is_predecessor: BoolProperty(name="Is Predecessor")
     is_successor: BoolProperty(name="Is Successor")
 

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

@@ -298,9 +298,20 @@ class BIM_UL_tasks(UIList):
             row.prop(item, "name", emboss=False, text="")
 
             if props.should_show_times:
-                row.prop(item, "start", emboss=False, text="")
-                row.prop(item, "finish", emboss=False, text="")
-                row.prop(item, "duration", emboss=False, text="")
+                if item.derived_start:
+                    row.label(text=item.derived_start + "*")
+                else:
+                    row.prop(item, "start", emboss=False, text="")
+
+                if item.derived_finish:
+                    row.label(text=item.derived_finish + "*")
+                else:
+                    row.prop(item, "finish", emboss=False, text="")
+
+                if item.derived_duration:
+                    row.label(text=item.derived_duration + "*")
+                else:
+                    row.prop(item, "duration", emboss=False, text="")
 
             if context.active_object:
                 oprops = context.active_object.BIMObjectProperties

src/ifcopenshell-python/ifcopenshell/util/date.py

@@ -7,21 +7,25 @@ except:
     pass  # Duration parsing not supported
 
 
+def timedelta2duration(timedelta):
+    components = {
+        "days": getattr(timedelta, "days", 0),
+        "hours": 0,
+        "minutes": 0,
+        "seconds": getattr(timedelta, "seconds", 0),
+    }
+    if components["seconds"]:
+        components["hours"], components["minutes"], components["seconds"] = [
+            int(i) for i in str(datetime.timedelta(seconds=components["seconds"])).split(":")
+        ]
+    return isodate.Duration(**components)
+
+
 def ifc2datetime(element):
     if isinstance(element, str) and element[0] == "P":  # IfcDuration
         duration = isodate.parse_duration(element)
         if isinstance(duration, datetime.timedelta):
-            components = {
-                "days": getattr(duration, "days", 0),
-                "hours": 0,
-                "minutes": 0,
-                "seconds": getattr(duration, "seconds", 0),
-            }
-            if components["seconds"]:
-                components["hours"], components["minutes"], components["seconds"] = [
-                    int(i) for i in str(datetime.timedelta(seconds=components["seconds"])).split(":")
-                ]
-            duration = isodate.Duration(**components)
+            return timedelta2duration(duration)
         return duration
     elif isinstance(element, str) and element[2] == ":":  # IfcTime
         return datetime.time.fromisoformat(element)