i'm trying through code to be able to iterate through all IfcProducts, and to list and IfcTask and IfcTaskTime properties.
for example i need to extract IfcTaskTime dates.
id: 464
type: IfcTaskTime
Name: ExampleTestNAme
DataOrigin: USERDEFINED
UserDefinedDataOrigin: None
DurationType: None
ScheduleDuration: None
ScheduleStart: 2025-12-01T08:00:00
ScheduleFinish: 2025-12-03T16:00:00
EarlyStart: None
EarlyFinish: None
LateStart: None
LateFinish: None
FreeFloat: None
TotalFloat: None
IsCritical: None
StatusTime: None
ActualDuration: None
ActualStart: None
ActualFinish: None
RemainingTime: None
Completion: None

i can find this information, but i cant seem to link it back to the IfcTask, which is linked with IfcProduct in this example.

IfcPile is in a relationship with IfcTask using IfcRealAssignedToProduct,
IfcTaskTime is in a relationship with IfcTask using IfcTealAssignedToProcess.
i can see this in the the .Ifc read in notepad. i just cant seem to figure out how to read IfcTaskTime, and see what IfcTask is associated an in turn also know which IfcProduct is assigned.

my latest attempt look like this, greatful for any support or ideas, where i might be going wrong

import ifcopenshell

Load the IFC file

ifc_file_path = r"location to ifc file"
ifc_file = ifcopenshell.open(ifc_file_path)
for rel in ifc_file.by_type("IfcRelAssignsToProcess"):
print(f"RelatingProcess: {rel.RelatingProcess}")
print(f"RelatedObjects: {rel.RelatedObjects}")

Debug: Print all IfcRelAssignsToProcess objects and their details

print("\n--- Debug: IfcRelAssignsToProcess Relationships ---")

for rel in ifc_file.by_type("IfcRelAssignsToProcess"):
print(f"RelatingProcess: {rel.RelatingProcess}")
print(f"RelatedObjects: {rel.RelatedObjects}")
for related_obj in rel.RelatedObjects:
print(f" RelatedObject: {related_obj}")
if related_obj.is_a("IfcTaskTime"):
print(f" Is a TaskTime: {related_obj}")
print(f" TaskTime ScheduleStart: {getattr(related_obj, 'ScheduleStart', 'No ScheduleStart')}")
print(f" TaskTime ScheduleFinish: {getattr(related_obj, 'ScheduleFinish', 'No ScheduleFinish')}")
print(f" TaskTime ScheduleDuration: {getattr(related_obj, 'ScheduleDuration', 'No ScheduleDuration')}")

Extract tasks related to IfcPile

tasks_related_to_piles = []
for rel in ifc_file.by_type("IfcRelAssignsToProduct"):
if rel.RelatingProduct.is_a("IfcPile"): # Check if relating object is IfcPile
tasks_related_to_piles.extend(rel.RelatedObjects)

Debug: List the tasks related to IfcPile

print("\n--- Debug: Tasks Related to IfcPile ---")
for task in tasks_related_to_piles:
print(f"Related Task: {task}")

Extract TaskTime relationships

results = []
for task in tasks_related_to_piles:
task_name = getattr(task, "Name", "Unnamed Task")
task_time_details = "No TaskTime Assigned"
print(f"Checking Task: {task_name} for TaskTime...")

for rel in ifc_file.by_type("IfcRelAssignsToProcess"):
    print(f"  Checking RelatingProcess: {rel.RelatingProcess}")

    if rel.RelatingProcess == task:  # Match task with process
        print(f"    Found related task: {task.Name}")
        for related_obj in rel.RelatedObjects:
            print(f"    Checking related object: {related_obj}")
            if related_obj.is_a("IfcTaskTime"):  # Check for IfcTaskTime
                task_time_details = f"Start: {getattr(related_obj, 'ScheduleStart', 'No Start Time')}, Finish: {getattr(related_obj, 'ScheduleFinish', 'No Finish Time')}, Duration: {getattr(related_obj, 'ScheduleDuration', 'No Duration')}"
                print(f"    Found TaskTime: {task_time_details}")
results.append((task_name, task_time_details))

Output results

print("\n--- Results: Task and TaskTime Details ---")
for task_name, task_time_details in results:
print(f"Task: {task_name}, TaskTime: {task_time_details}")