Module Contents#

class ifcopenshell.api.sequence.calculate_task_duration.Usecase(file, task=None)#

Calculates the task duration based on resource usage

If a task has labour or equipment resources assigned to it, its duration may be parametrically derived from the scheduled work of the resource. For example, a labour resource with scheduled work of 10 working days and a resource utilisation of 200% (i.e. two labour teams) will imply that the task duration is 5 working days.

If this data is not available, such as if the task has no resources, then nothing happens.


task (ifcopenshell.entity_instance.entity_instance) – The IfcTask to calculate the duration for.



Return type



# Add our own crew
crew = ifcopenshell.api.run("resource.add_resource", model, ifc_class="IfcCrewResource")

# Add some labour to our crew.
labour = ifcopenshell.api.run("resource.add_resource", model,
    parent_resource=crew, ifc_class="IfcLaborResource")

# Labour resource is quantified in terms of time.
quantity = ifcopenshell.api.run("resource.add_resource_quantity", model,
    resource=labour, ifc_class="IfcQuantityTime")

# Store the unit time used in hours
ifcopenshell.api.run("resource.edit_resource_quantity", model,
    physical_quantity=quantity, attributes={"TimeValue": 8.0})

# Let's imagine we've used the resource for 10 days with a
# utilisation of 200%.
time = ifcopenshell.api.run("resource.add_resource_time", model, resource=labour)
ifcopenshell.api.run("resource.edit_resource_time", model,
    resource_time=time, attributes={"ScheduleWork": "PT80H", "ScheduleUsage": 2})

# Let's imagine we are creating a construction schedule. All tasks
# need to be part of a work schedule.
schedule = ifcopenshell.api.run("sequence.add_work_schedule", model, name="Construction Schedule A")

# Let's create a construction task. Note that the predefined type is
# important to distinguish types of tasks.
task = ifcopenshell.api.run("sequence.add_task", model,
    work_schedule=schedule, name="Foundations", identification="A")

# Assign our resource to the task.
ifcopenshell.api.run("sequence.assign_process", model, relating_process=task, related_object=labour)

# Now we can calculate the task duration based on the resource. This
# will set task.TaskTime.ScheduleDuration to be P5D.
ifcopenshell.api.run("sequence.calculate_task_duration", model, task=task)
calculate_duration_in_days(self, resource)#
set_task_duration(self, duration)#