`ifcopenshell.api.sequence`¶

Manage work schedules, tasks, calendars, and more for 4D

These are typically used for construction planning, but may also be used in managing recurring facility maintenance schedules.

Submodules¶

Package Contents¶

ifcopenshell.api.sequence.add_task(file: ifcopenshell.file, work_schedule: ifcopenshell.entity_instance | None = None, parent_task: ifcopenshell.entity_instance | None = None, name: str | None = None, description: str | None = None, identification: str | None = None, predefined_type: str = 'NOTDEFINED') → ifcopenshell.entity_instance¶

Adds a new task

Tasks are typically used for two purposes: construction scheduling and facility management.

In construction scheduling, a task represents a job to be done in a work schedule. Tasks are organised in a hierarchical manner known as a work breakdown structure (WBS) and have lots of sequential relationships (e.g. this task must finish before the next task can start) and date information (e.g. durations, start dates). This is often represented as a gantt chart and used to analyse critical paths to try and reduce project time to stay on-time and within budget.

In facility management, a task represents a maintenance task to maintain a piece of equipment. Tasks are broken down into a punch list, or simply a bulleted or ordered sequence of tasks to be performed (e.g. turn off equipment, check power connection, etc) in order to maintain the equipment. Tasks will also typically have recurring scheduled dates in line with the maintenance schedule. These maintenance tasks and procedures are typically published as part of an operations and maintenance manual.

All tasks must be grouped in a work schedule, either directly as a root or top-level task, or indirectly as a child or subtask of a parent task. In construction scheduling, tasks may be nested many times to create the work breakdown structure, and the “leaf” tasks (i.e. tasks with no more subtasks) are considered to be the activities with dates, whereas all parent tasks are part of the breakdown structure used for categorisation purposes. In facility management, top-level tasks represent the overall maintenance job to be performed, and child tasks represent an ordered list of things to do for that maintenance. These form a 2-level hierarchy. No further child tasks are recommended.

Parameters:

work_schedule (ifcopenshell.entity_instance, optional) – The work schedule to group the task in, if the task is to be a top-level or root task. This is mutually exclusive with the parent_task parameter.
parent_task (ifcopenshell.entity_instance, optioanl) – The parent task, if the task is to be a subtask or child task. This is mutually exclusive with the work_schedule parameter.
name (str,optional) – The name of the task.
description (str,optional) – The description of the task.
identification (str,optional) – The identification code of the task.
predefined_type (str) – The predefined type of the task. Common ones include CONSTRUCTION, DEMOLITION, or MAINTENANCE. Consultant the IFC documentation for IfcTaskTypeEnum for more information.

Returns:

The newly created IfcTask

Return type:

ifcopenshell.entity_instance

Example:

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

# Add a root task to represent the design milestones, and major
# project phases.
ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Milestones", identification="A")
ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Design", identification="B")
construction = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Construction", identification="C")

# Let's start creating our work breakdown structure.
ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Early Works", identification="C1")
ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Substructure", identification="C2")
superstructure = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Superstructure", identification="C3")

# Notice how the leaf task is the actual activity
ifcopenshell.api.sequence.add_task(model,
    parent_task=superstructure, name="Ground Floor FRP", identification="C3.1")

# Let's imagine we are digitising an operations and maintenance
# manual for the mechanical discipline.
maintenance = ifcopenshell.api.sequence.add_work_schedule(model, name="Mechanical Maintenance")

# Imagine we have to clean the condenser coils for a chiller every
# month. Like the schedule above, to keep things simple we won't
# show scheduling times and calendars. This root task represents the
# overall maintenance task.
cleaning = ifcopenshell.api.sequence.add_task(model,
    work_schedule=maintenance, name="Condenser coil cleaning")

# These subtasks represent the punch list of maintenance tasks.
ifcopenshell.api.sequence.add_task(model, parent_task=cleaning, identification="1",
    description="Prior to work, wear safety shoes, gloves, and goggles.")
ifcopenshell.api.sequence.add_task(model, parent_task=cleaning, identification="2",
    description="Prepare jet pump, screwdriver, hose clamp, and control panel door key.")
ifcopenshell.api.sequence.add_task(model, parent_task=cleaning, identification="3",
    description="Switch OFF the chiller unit.")
ifcopenshell.api.sequence.add_task(model, parent_task=cleaning, identification="3",
    description="Open the isolator switch.")
ifcopenshell.api.sequence.add_task(model, parent_task=cleaning, identification="3",
    description="Setup the water pressure by tapping to a water supply and connecting to a ...")

ifcopenshell.api.sequence.add_task_time(file: ifcopenshell.file, task: ifcopenshell.entity_instance, is_recurring: bool = False) → ifcopenshell.entity_instance¶

Adds a task time to a task

Some tasks, such as activities within a work breakdown structure or overall maintenance tasks will have time related information. This includes start dates, durations, end dates, and possible recurring times (especially for maintenance tasks).

Parameters:

task (ifcopenshell.entity_instance) – The task to add time data to.
is_recurring (bool) – Whether or not the time should recur.

Returns:

The newly created IfcTaskTime.

Return type:

ifcopenshell.entity_instance

Example:

# Let's imagine we are creating a construction schedule.
schedule = ifcopenshell.api.sequence.add_work_schedule(model, name="Construction Schedule A")

# Create a portion of a work breakdown structure.
construction = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Construction", identification="C")
superstructure = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Superstructure", identification="C3")
task = ifcopenshell.api.sequence.add_task(model,
    parent_task=superstructure, name="Ground Floor FRP", identification="C3.1")

# Add time data. Note that time data is blank by default.
time = ifcopenshell.api.sequence.add_task_time(model, task=task)

# Let's say our task starts on the first of January when everybody
# is still drunk from the new years celebration, and lasts for 2
# days. Note we don't need to specify the end date, as that is
# derived from the start plus the duration. In this simple example,
# no calendar has been specified, so we are working 24/7. Yikes!
ifcopenshell.api.sequence.edit_task_time(model,
    task_time=time, attributes={"ScheduleStart": "2000-01-01", "ScheduleDuration": "P2D"})

ifcopenshell.api.sequence.add_time_period(file: ifcopenshell.file, recurrence_pattern: ifcopenshell.entity_instance, start_time: str | datetime.time | None = None, end_time: str | datetime.time | None = None) → ifcopenshell.entity_instance¶

Adds a time period to a recurrence pattern

A recurring time may be an all-day event, or only during certain time periods of the day. For example, you might say that every 1st of January recurring is a public holiday, which is an all-day event. Alternatively, you might say that you work every (i.e. recurringly) Monday to Friday, from 9am to 5pm. The 9am to 5pm is the time period.

There may also be multiple recurrence patterns, such as from 9am to 12pm, and then another from 1pm to 5pm (to indicate an hour break for lunch).

Parameters:

recurrence_pattern (ifcopenshell.entity_instance) – The IfcRecurrencePattern to add the time period to. See ifcopenshell.api.sequence.assign_recurrence_pattern.
start_time (str,datetime.time) – The start time of the time period, in a format compatible with IfcTime, such as an ISO format time string or a datetime.time object.
end_time (str,datetime.time) – The end time of the time period, in a format compatible with IfcTime, such as an ISO format time string or a datetime.time object.

Returns:

The newly created IfcTimePeriod

Return type:

ifcopenshell.entity_instance

Example:

# Let's create a new calendar.
calendar = ifcopenshell.api.sequence.add_work_calendar(model)

# Let's start defining the times that we work during the week.
work_time = ifcopenshell.api.sequence.add_work_time(model,
    work_calendar=calendar, time_type="WorkingTimes")

# We create a weekly recurrence
pattern = ifcopenshell.api.sequence.assign_recurrence_pattern(model,
    parent=work_time, recurrence_type="WEEKLY")

# State that we work from weekdays 1 to 5 (i.e. Monday to Friday)
ifcopenshell.api.sequence.edit_recurrence_pattern(model,
    recurrence_pattern=pattern, attributes={"WeekdayComponent": [1, 2, 3, 4, 5]})

# The morning work session, lunch, then the afternoon work session.
ifcopenshell.api.sequence.add_time_period(model,
    recurrence_pattern=pattern, start_time="09:00", end_time="12:00")
ifcopenshell.api.sequence.add_time_period(model,
    recurrence_pattern=pattern, start_time="13:00", end_time="17:00")

ifcopenshell.api.sequence.add_work_calendar(file: ifcopenshell.file, name: str = 'Unnamed', predefined_type: str = 'NOTDEFINED') → ifcopenshell.entity_instance¶

Add a work calendar

A work calendar defines when work is allowed to occur and when the holidays are. This is a fundamental concept in construction planning. Every task in a work schedule will have an associated calendar. Some task and resources work 24/7, whereas others work Monday to Friday, or 5.5 day weeks, etc. This is important, as tasks durations may only occur during working times in a work calendar.

Work calendars can also be used to associate with events, such as indicating that during certain days and times of the year, motion sensors should turn on the lights, and other smart building controls.

Parameters:

name (str, optional) – The name of the calendar. Typically something like “5 Day Working Week” or “24/7”.
predefined_type – The type of calendar, typically used to more specifically define shifts, such as FIRSTSHIFT, SECONDSHIFT, or THIRDSHIFT. Leave as NOTDEFINED for basic calendar usage.

Returns:

The newly created IfcWorkCalendar

Return type:

ifcopenshell.entity_instance

Example:

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

# Add a root task to represent the construction tasks.
task = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Construction", identification="C")

# Let's create a new calendar.
calendar = ifcopenshell.api.sequence.add_work_calendar(model, name="5 Day Week")

# Let's start defining the times that we work during the week.
work_time = ifcopenshell.api.sequence.add_work_time(model,
    work_calendar=calendar, time_type="WorkingTimes")

# We create a weekly recurrence
pattern = ifcopenshell.api.sequence.assign_recurrence_pattern(model,
    parent=work_time, recurrence_type="WEEKLY")

# State that we work from weekdays 1 to 5 (i.e. Monday to Friday), 9am to 5pm
ifcopenshell.api.sequence.edit_recurrence_pattern(model,
    recurrence_pattern=pattern, attributes={"WeekdayComponent": [1, 2, 3, 4, 5]})
ifcopenshell.api.sequence.add_time_period(model,
    recurrence_pattern=pattern, start_time="09:00", end_time="17:00")

# We associate the calendar with the construction root task. All
# subtasks underneath the construction work task will also inherit
# this calendar by default (though you can override them).
ifcopenshell.api.control.assign_control(model, relating_control=calendar, related_object=task)

ifcopenshell.api.sequence.add_work_plan(file: ifcopenshell.file, name: str | None = None, predefined_type: str = 'NOTDEFINED', start_time: str | datetime.time | None = None) → ifcopenshell.entity_instance¶

Add a new work plan

A work plan is a group of work schedules. Since work schedules may have different purposes, such as for maintenance or construction scheduling, baseline comparison, or phasing, work plans can be used to group related work schedules. At a minimum, it is recommended to use work plans to indicate whether the work schedules are for facility management or for construction scheduling.

Parameters:

name (str, optional) – The name of the work plan. Recommended to be “Maintenance” or “Construction” for the two main purposes.
predefined_type (str) – The type of work plan, used for baselining. Leave as “NOTDEFINED” if unsure.
start_time (str,datetime.time) – The earliest start time when the schedules grouped within the work plan are relevant.

Returns:

The newly created IfcWorkPlan

Return type:

ifcopenshell.entity_instance

Example:

# This will hold all our construction schedules
work_plan = ifcopenshell.api.sequence.add_work_plan(model, name="Construction")

# This is one of our schedules in our work plan.
schedule = ifcopenshell.api.sequence.add_work_schedule(model,
    name="Construction Schedule A", work_plan=work_plan)

ifcopenshell.api.sequence.add_work_schedule(file: ifcopenshell.file, name: str = 'Unnamed', predefined_type: str = 'NOTDEFINED', object_type=None, start_time: str | datetime.time | None = None, work_plan: ifcopenshell.entity_instance | None = None) → ifcopenshell.entity_instance¶

Add a new work schedule

A work schedule is a group of tasks, where the tasks are typically either for maintenance or for construction scheduling.

Parameters:

name (str) – The name of the work schedule.
predefined_type (str) – The type of schedule, chosen from ACTUAL, BASELINE, and PLANNED. Typically you would start with PLANNED, then convert to a BASELINE when changes are made with separate schedules, then have a parallel ACTUAL schedule.
start_time (str,datetime.time,optional) – The earlier start time when the schedule is relevant. May be represented with an ISO standard string.
work_plan (ifcopenshell.entity_instance,optional) – The IfcWorkPlan the schedule will be part of. If not provided, the schedule will not be grouped in a work plan and would exist as a top level schedule in the project. This is not recommended.

Returns:

The newly created IfcWorkSchedule

Return type:

ifcopenshell.entity_instance

Example:

# This will hold all our construction schedules
work_plan = ifcopenshell.api.sequence.add_work_plan(model, name="Construction")

# Let's imagine this is one of our schedules in our work plan.
schedule = ifcopenshell.api.sequence.add_work_schedule(model,
    name="Construction Schedule A", work_plan=work_plan)

# Add a root task to represent the design milestones, and major
# project phases.
ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Milestones", identification="A")
ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Design", identification="B")
construction = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Construction", identification="C")

ifcopenshell.api.sequence.add_work_time(file: ifcopenshell.file, work_calendar: ifcopenshell.entity_instance, time_type: TIME_TYPE = 'WorkingTimes') → ifcopenshell.entity_instance¶

Add either working times or holiday times to a calendar

A calendar defines when work occurs by defining working times and holiday times. First, the working times are defined, then the holidays may override the working times. For this reason, holidays are also known as exception times. For example, you might define the working times as every Monday to Friday, then define a few holidays in the year, such as the 1st of January. If the 1st of January is on a weekday, it will override the work time.

Parameters:

work_calendar (ifcopenshell.entity_instance) – The IfcWorkCalendar to add the work or holiday time definition to.
time_type (str) – Either WorkingTimes or ExceptionTimes, depending on what you want to define.

Returns:

The newly created IfcWorkTime

Return type:

ifcopenshell.entity_instance

Example:

# Let's create a new calendar.
calendar = ifcopenshell.api.sequence.add_work_calendar(model)

# Let's start defining the times that we work during the week.
work_time = ifcopenshell.api.sequence.add_work_time(model,
    work_calendar=calendar, time_type="WorkingTimes")

# We create a weekly recurrence
pattern = ifcopenshell.api.sequence.assign_recurrence_pattern(model,
    parent=work_time, recurrence_type="WEEKLY")

# State that we work from weekdays 1 to 5 (i.e. Monday to Friday)
ifcopenshell.api.sequence.edit_recurrence_pattern(model,
    recurrence_pattern=pattern, attributes={"WeekdayComponent": [1, 2, 3, 4, 5]})

# Let's set some holidays
holidays = ifcopenshell.api.sequence.add_work_time(model,
    work_calendar=calendar, time_type="ExceptionTimes")

# We create a yearly recurrence
pattern = ifcopenshell.api.sequence.assign_recurrence_pattern(model,
    parent=work_time, recurrence_type="YEARLY_BY_DAY_OF_MONTH")

# The holiday is every 1st of January
ifcopenshell.api.sequence.edit_recurrence_pattern(model,
    recurrence_pattern=pattern, attributes={"DayComponent": [1], "MonthComponent": [1]})

ifcopenshell.api.sequence.assign_lag_time(file: ifcopenshell.file, rel_sequence: ifcopenshell.entity_instance, lag_value: str, duration_type: str = 'WORKTIME') → ifcopenshell.entity_instance¶

Assign a lag time to a sequence relationship between tasks

A task sequence (e.g. finish to start) may optionally have a lag time defined. This is a fundamental concept in construction scheduling. The lag is defined as a duration, and the duration is typically either calendar based (i.e. follows the working times and holidays of the calendar) or elapsed time based (i.e. 24/7).

A sequence may only have a single lag time defined. Negative lag times are allowed.

Parameters:

rel_sequence (ifcopenshell.entity_instance) – The IfcRelSequence to assign the lag time to.
lag_value (str) – An ISO standardised duration string.
duration_type (str) – Choose from WORKTIME for the associated calendar-based lag times (this is the most common scenario and is recommended as a default), or ELAPSEDTIME to not follow the calendar. You may also choose NOTDEFINED but the behaviour of this is unclear.

Returns:

The newly created IfcLagTime

Return type:

ifcopenshell.entity_instance

Example:

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

# Let's imagine a root construction task
construction = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Construction", identification="C")

# Let's imagine we're doing a typically formwork, reinforcement,
# pour sequence. Let's start with the formwork. It'll take us 2
# days.
formwork = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Formwork", identification="C.1")
time = ifcopenshell.api.sequence.add_task_time(model, task=formwork)
ifcopenshell.api.sequence.edit_task_time(model,
    task_time=time, attributes={"ScheduleStart": "2000-01-01", "ScheduleDuration": "P2D"})

# Now let's do the reinforcement. It'll take us another 2 days.
reinforcement = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Reinforcement", identification="C.2")
time = ifcopenshell.api.sequence.add_task_time(model, task=reinforcement)
ifcopenshell.api.sequence.edit_task_time(model,
    task_time=time, attributes={"ScheduleStart": "2000-01-01", "ScheduleDuration": "P2D"})

# Now let's say the formwork must finish before the reinforcement
# can start. This is a typical finish to start relationship (FS).
sequence = ifcopenshell.api.sequence.assign_sequence(model,
    relating_process=formwork, related_process=reinforcement)

# Now typically there would be no lag time between formwork and
# reinforcement, but let's pretend that we had to allow 1 day gap
# for whatever reason.
ifcopenshell.api.sequence.assign_lag_time(model, rel_sequence=sequence, lag_value="P1D")

ifcopenshell.api.sequence.assign_process(file: ifcopenshell.file, relating_process: ifcopenshell.entity_instance, related_object: ifcopenshell.entity_instance) → ifcopenshell.entity_instance¶

Assigns an object to be related to a process, typically a construction task

Processes work using the ICOM (Input, Controls, Outputs, Mechanisms) paradigm in IFC. This process model is commonly used in modeling manufacturing functions.

For example, processes (such as tasks) consume Inputs and transform them into Outputs. The process may only occur within the limits of Controls (e.g. cost items) and may require Mechanisms (ISO9000 calls them Mechanisms, whereas IFC calls them resources, such as raw materials, labour, or equipment).

Controls

V

+——–+ +———+ +———+ | Inputs | –> | Process | –> | Outputs | +——–+ +———+ +———+

Resources

There are three main scenarios where an object may be related to a task: defining inputs, controls, and resources of a process.

For inputs, a product (i.e. wall) may be defined as an input to a task, such as when the task is to demolish the wall (i.e. the wall is an input, and there is no output).

For controls, a cost item may be defined as a control to a task.

For resources, any construction resource may be assigned to a task.

Parameters:

relating_process (ifcopenshell.entity_instance) – The IfcProcess (typically IfcTask) that the input, control, or resource is related to.
related_object (ifcopenshell.entity_instance) – The IfcProduct (for input), IfcCostItem (for control) or IfcConstructionResource (for resource).

Returns:

The newly created IfcRelAssignsToProcess relationship

Return type:

ifcopenshell.entity_instance

Example:

# Let's imagine we are creating a construction schedule. All tasks
# need to be part of a work schedule.
schedule = ifcopenshell.api.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.sequence.add_task(model,
    work_schedule=schedule, name="Demolish existing", identification="A", predefined_type="DEMOLITION")

# Let's say we have a wall somewhere.
wall = ifcopenshell.api.root.create_entity(model, ifc_class="IfcWall")

# Let's demolish that wall!
ifcopenshell.api.sequence.assign_process(model, relating_process=task, related_object=wall)

ifcopenshell.api.sequence.assign_product(file: ifcopenshell.file, relating_product: ifcopenshell.entity_instance, related_object: ifcopenshell.entity_instance) → ifcopenshell.entity_instance¶

Assigns a product to be produced as a result of a process

A construction task may result in products (e.g. a wall) being constructed. These task “Outputs” are defined in IFC through product relationships.

Not all tasks have Outputs. For example, maintenance tasks will typically not have any outputs.

See ifcopenshell.api.sequence.assign_process for Inputs and other types of process relationships that can be described in manufacturing process modeling.

Parameters:

relating_product (ifcopenshell.entity_instance) – The IfcProduct that was constructed as a result of the task.
related_object (ifcopenshell.entity_instance) – The IfcProcess (typically IfcTask) of the construction task.

Returns:

The newly created IfcRelAssignsToProduct relationship

Return type:

ifcopenshell.entity_instance

Example:

# Let's imagine we are creating a construction schedule. All tasks
# need to be part of a work schedule.
schedule = ifcopenshell.api.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.sequence.add_task(model,
    work_schedule=schedule, name="Build wall", identification="A", predefined_type="CONSTRUCTION")

# Let's say we have a wall somewhere.
wall = ifcopenshell.api.root.create_entity(model, ifc_class="IfcWall")

# Let's construct that wall!
ifcopenshell.api.sequence.assign_product(model, relating_product=wall, related_object=task)

ifcopenshell.api.sequence.assign_recurrence_pattern(file: ifcopenshell.file, parent: ifcopenshell.entity_instance, recurrence_type: ifcopenshell.util.sequence.RECURRENCE_TYPE = 'WEEKLY') → ifcopenshell.entity_instance¶

Define a time to recur at a particular interval

There are two scenarios where you might want to define a recurring time pattern.

You might want a task to be scheduled at a recurring interval, this is common for maintenance tasks which need to be performed monthly, every 6 months, every year, etc.

Alternatively, you might be defining a work calendar, which defines working days or holidays. The working days might be every week from monday to friday (“every” week means it recurs every week), or the holidays might be the same every year.

The types of recurrence are:

DAILY: every Nth (interval) day for up to X (Occurrences) occurrences.
e.g. Every day, every 2 days, every day up to 5 times, etc
WEEKLY: every Nth (interval) MTWTFSS (WeekdayComponent) for up to X
(Occurrences) occurrences. e.g. Every Monday, every weekday, every other saturday, etc
MONTHLY_BY_DAY_OF_MONTH: every Nth (DayComponent) of every Xth
(Interval) Month up to Y (Occurrences) occurrences. e.g. Every 15th of the Month.
MONTHLY_BY_POSITION: Every Nth (Position) MTWTFSS (WeekdayComponent)
of every Xth (Interval) Month up to Y (Occurrences) occurrences. e.g. Every second Tuesday of the Month.
YEARLY_BY_DAY_OF_MONTH: every Nth (DayComponent) of every JFMAMJJASOND
(MonthComponent) month of every Yth (Interval) Year up to Z (Occurrences) occurrences. e.g. every 25th of December.
YEARLY_BY_POSITION: every Nth (Position) MTWTFSS (WeekdayComponent) of
every JFMAMJJASOND (MonthComponent) month of every Yth (Interval) Year up to Z (Occurrences) occurrences. e.g. every third Wednesday of January.

These recurrence patterns are fairly standard in all calendar and scheduling applications.

Parameters:

parent (ifcopenshell.entity_instance) – Either an IfcTaskTimeRecurring if you are defining a recurring schedule for a task, or IfcWorkTime if you are defining a recurring pattern for a workdays or holidays in a calendar.
recurrence_type (str) – One of the types of recurrences.

Returns:

The newly created IfcRecurrencePattern

Return type:

ifcopenshell.entity_instance

Example:

# Let's create a new calendar.
calendar = ifcopenshell.api.sequence.add_work_calendar(model)

# Let's start defining the times that we work during the week.
work_time = ifcopenshell.api.sequence.add_work_time(model,
    work_calendar=calendar, time_type="WorkingTimes")

# We create a weekly recurrence
pattern = ifcopenshell.api.sequence.assign_recurrence_pattern(model,
    parent=work_time, recurrence_type="WEEKLY")

# State that we work from weekdays 1 to 5 (i.e. Monday to Friday)
ifcopenshell.api.sequence.edit_recurrence_pattern(model,
    recurrence_pattern=pattern, attributes={"WeekdayComponent": [1, 2, 3, 4, 5]})

# Let's imagine we are creating a maintenance schedule.
schedule = ifcopenshell.api.sequence.add_work_schedule(model, name="Equipment Maintenance")

# Now let's imagine we have a task to maintain the chillers
task = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Chiller maintenance")

# Because it is a maintenance task, we must schedule a recurring time
time = ifcopenshell.api.sequence.add_task_time(model, task=task, is_recurring=True)

# We create a monthly recurrence
pattern = ifcopenshell.api.sequence.assign_recurrence_pattern(model,
    parent=work_time, recurrence_type="MONTHLY_BY_DAY_OF_MONTH")

# Specifically, the maintenance task must occur every 6 months
ifcopenshell.api.sequence.edit_recurrence_pattern(model,
    recurrence_pattern=pattern, attributes={"DayComponent": [1], "Interval": 6})

ifcopenshell.api.sequence.assign_sequence(file: ifcopenshell.file, relating_process: ifcopenshell.entity_instance, related_process: ifcopenshell.entity_instance, sequence_type: str = 'FINISH_START') → ifcopenshell.entity_instance¶

Assign a sequential relationship between tasks

Tasks in construction sequencing typically have sequence relationships between them, indicating that one task must happen after another. This is used to automatically compute new start and end dates and cascade changes when dates are changed. This is also used to calculate critical paths and floats.

There are four types of sequence relationships, known as finish to start, finish to finish, start to start, and start to finish, sometimes abbreviated as a (FS, FF, SS, and SF). The most common is the finish to start relationship, indicating that the previous task must finish before the next task can start.

You must not create cyclical task sequences. This makes the computer unhappy.

Note that “previous” or “next” does not necessarily mean the task chronologically happens before or after. They simply indicate the order of the sequence relationship. For this reason, they are often called predecessor and successor tasks in the planning profession.

Parameters:

relating_process (ifcopenshell.entity_instance) – The previous / predecessor task.
related_process (ifcopenshell.entity_instance) – The next / successor task.
sequence_type – Choose from FINISH_START, FINISH_FINISH, START_START, or START_FINISH.

Returns:

The newly created IfcRelSequence

Return type:

ifcopenshell.entity_instance

Example:

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

# Let's imagine a root construction task
construction = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Construction", identification="C")

# Let's imagine we're doing a typically formwork, reinforcement,
# pour sequence. Let's start with the formwork. It'll take us 2
# days.
formwork = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Formwork", identification="C.1")
time = ifcopenshell.api.sequence.add_task_time(model, task=formwork)
ifcopenshell.api.sequence.edit_task_time(model,
    task_time=time, attributes={"ScheduleStart": "2000-01-01", "ScheduleDuration": "P2D"})

# Now let's do the reinforcement. It'll take us another 2 days.
reinforcement = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Reinforcement", identification="C.2")
time = ifcopenshell.api.sequence.add_task_time(model, task=reinforcement)
ifcopenshell.api.sequence.edit_task_time(model,
    task_time=time, attributes={"ScheduleStart": "2000-01-01", "ScheduleDuration": "P2D"})

# Now the pour it It'll only take 1 day.
pour = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Reinforcement", identification="C.3")
time = ifcopenshell.api.sequence.add_task_time(model, task=pour)
ifcopenshell.api.sequence.edit_task_time(model,
    task_time=time, attributes={"ScheduleStart": "2000-01-01", "ScheduleDuration": "P1D"})

# Now let's say the formwork must finish before the reinforcement
# can start, and the reinforcement must finish before the pour can
# start. This is a typical finish to start relationship (FS).
ifcopenshell.api.sequence.assign_sequence(model,
    relating_process=formwork, related_process=reinforcement)
ifcopenshell.api.sequence.assign_sequence(model,
    relating_process=reinforcement, related_process=pour)

# Notice how we set all the scheduled start dates arbitrarily at
# 2000-01-01. This is because we can ask IfcOpenShell to
# automatically cascade the dates, starting from any task. This will
# update the reinforcement date to be 2000-01-03 and the pour date
# to be 2000-01-05.
ifcopenshell.api.sequence.cascade_schedule(model, task=formwork)

ifcopenshell.api.sequence.assign_work_plan(file: ifcopenshell.file, work_schedule: ifcopenshell.entity_instance, work_plan: ifcopenshell.entity_instance) → ifcopenshell.entity_instance¶

Assigns a work schedule to a work plan

Typically, work schedules would be assigned to a work plan at creation. However you may also delay this and do it manually afterwards.

Parameters:

work_schedule (ifcopenshell.entity_instance) – The IfcWorkSchedule that will be assigned to the work plan.
work_plan (ifcopenshell.entity_instance) – The IfcWorkPlan for the schedule to be assigned to.

Returns:

The IfcRelAggregates relationship

Return type:

ifcopenshell.entity_instance

Example:

# This will hold all our construction schedules
work_plan = ifcopenshell.api.sequence.add_work_plan(model, name="Construction")

# Alternatively, if you create a schedule without a work plan ...
schedule = ifcopenshell.api.sequence.add_work_schedule(model, name="Construction Schedule A")

# ... you can assign the work plan afterwards.
ifcopenshell.api.sequence.assign_work_plan(work_schedule=schedule, work_plan=work_plan)

ifcopenshell.api.sequence.calculate_task_duration(file: ifcopenshell.file, task: ifcopenshell.entity_instance) → 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.

Parameters:: task (ifcopenshell.entity_instance) – The IfcTask to calculate the duration for.
Returns:: None
Return type:: None

Example:

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

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

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

# Store the unit time used in hours
ifcopenshell.api.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.resource.add_resource_time(model, resource=labour)
ifcopenshell.api.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.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.sequence.add_task(model,
    work_schedule=schedule, name="Foundations", identification="A")

# Assign our resource to the task.
ifcopenshell.api.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.sequence.calculate_task_duration(model, task=task)

ifcopenshell.api.sequence.cascade_schedule(file: ifcopenshell.file, task: ifcopenshell.entity_instance) → None¶

Cascades start and end dates of tasks based on durations

Given a start task with a start date and duration, the end date, and the start and end of all successor tasks with durations may be automatically computed.

Using this automatic computation is recommended is an alternative to manually specifying dates. It is useful for doing edits and cascading changes.

Dates can only cascade from predecessor to successors, not backwards. Cyclical relationships are invalid and will result in a recursion error being raised.

Note that there may be differences between how different planning software calculate start and end dates. Some may consider Monday 5pm to be equivalent to be Tuesday 8am, for instance.

Parameters:: task (ifcopenshell.entity_instance) – The start task to begin cascading from.
Returns:: None
Return type:: None

Example:

# Define a convenience function to add a task chained to a predecessor
def add_task(model, name, predecessor, work_schedule):
    # Add a construction task
    task = ifcopenshell.api.sequence.add_task(model,
        work_schedule=work_schedule, name=name, predefined_type="CONSTRUCTION")

    # Give it a time
    task_time = ifcopenshell.api.sequence.add_task_time(model, task=task)

    # Arbitrarily set the task's scheduled time duration to be 1 week
    ifcopenshell.api.sequence.edit_task_time(model, task_time=task_time,
        attributes={"ScheduleStart": datetime.date(2000, 1, 1), "ScheduleDuration": "P1W"})

    # If a predecessor exists, create a finish to start relationship
    if predecessor:
        ifcopenshell.api.sequence.assign_sequence(model,
            relating_process=predecessor, related_process=task)

    return task

# Open an existing IFC4 model you have of a building
model = ifcopenshell.open("/path/to/existing/model.ifc")

# Create a new construction schedule
schedule = ifcopenshell.api.sequence.add_work_schedule(model, name="Construction")

# Let's imagine a starting task for site establishment.
task = add_task(model, "Site establishment", None, schedule)
start_task = task

# Get all our storeys sorted by elevation ascending.
storeys = sorted(model.by_type("IfcBuildingStorey"), key=lambda s: get_storey_elevation(s))

# For each storey ...
for storey in storeys:

    # Add a construction task to construct that storey, using our convenience function
    task = add_task(model, f"Construct {storey.Name}", task, schedule)

    # Assign all the products in that storey to the task as construction outputs.
    for product in get_decomposition(storey):
        ifcopenshell.api.sequence.assign_product(model, relating_product=product, related_object=task)

# Ask the computer to calculate all the dates for us from the start task.
# For example, if the first task started on the 1st of January and took a
# week, the next task will start on the 8th of January. This saves us
# manually doing date calculations.
ifcopenshell.api.sequence.cascade_schedule(model, task=start_task)

# Calculate the critical path and floats.
ifcopenshell.api.sequence.recalculate_schedule(model, work_schedule=schedule)

ifcopenshell.api.sequence.create_baseline(file: ifcopenshell.file, work_schedule: ifcopenshell.entity_instance, name: str | None = None) → None¶

Creates a baseline for your Work Schedule

Using a IfcWorkSchdule having PredefinedType=PLANNED, We can create a baseline for our work schedule. This IfcWorkSchedule will have PredefinedType=BASELINE and the IfcWorkSchedule.CreationDate indicating the date of the baseline creation, and IfcWorkSchedule.Name indicating the name of the baseline.

The following relationships are also baselined:

Same Tasks & attributes
Same Task Relationships
Same Construction Resources
Same Resource Relationships

Parameters:

work_schedule (ifcopenshell.entity_instance) – The planned work_schedule to baseline
name (str, optional) – baseline work schedule name

Returns:

The baseline work_schedule

Return type:

ifcopenshell.entity_instance

Example:

# We have a Work Schedule
planned_work_schedule = WorkSchedule(name="Design new feature",predefinedType="PLANNED", deadline="2023-03-01")

# And now we have a baseline for our Work Schedule
baseline_work_schedule = ifcopenshell.api.sequence.create_baseline(file, work_schedule=planned_work_schedule, name="Baseline 1")

ifcopenshell.api.sequence.duplicate_task(file: ifcopenshell.file, task: ifcopenshell.entity_instance) → ifcopenshell.entity_instance¶

Duplicates a task in the project

The following relationships are also duplicated:

The copy will have the same attributes and property sets as the original task
The copy will be assigned to the parent task or work schedule
The copy will have duplicated nested tasks

Parameters:: task (ifcopenshell.entity_instance) – The task to be duplicated
Returns:: The duplicated task or the list of duplicated tasks if the latter has children
Return type:: ifcopenshell.entity_instance or list of ifcopenshell.entity_instance

Example: .. code:: python

# We have a task original_task = Task(name=”Design new feature”, deadline=”2023-03-01”)

# And now we have two duplicated_task = project.duplicate_task(original_task)

ifcopenshell.api.sequence.edit_lag_time(file: ifcopenshell.file, lag_time: ifcopenshell.entity_instance, attributes: dict[str, Any]) → None¶

Edits the attributes of an IfcLagTime

For more information about the attributes and data types of an IfcLagTime, consult the IFC documentation.

Parameters:

lag_time (ifcopenshell.entity_instance) – The IfcLagTime entity you want to edit
attributes (dict) – a dictionary of attribute names and values.

Returns:

None

Return type:

None

Example:

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

# Let's imagine a root construction task
construction = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Construction", identification="C")

# Let's imagine we're doing a typically formwork, reinforcement,
# pour sequence. Let's start with the formwork. It'll take us 2
# days.
formwork = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Formwork", identification="C.1")
time = ifcopenshell.api.sequence.add_task_time(model, task=formwork)
ifcopenshell.api.sequence.edit_task_time(model,
    task_time=time, attributes={"ScheduleStart": "2000-01-01", "ScheduleDuration": "P2D"})

# Now let's do the reinforcement. It'll take us another 2 days.
reinforcement = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Reinforcement", identification="C.2")
time = ifcopenshell.api.sequence.add_task_time(model, task=reinforcement)
ifcopenshell.api.sequence.edit_task_time(model,
    task_time=time, attributes={"ScheduleStart": "2000-01-01", "ScheduleDuration": "P2D"})

# Now let's say the formwork must finish before the reinforcement
# can start. This is a typical finish to start relationship (FS).
sequence = ifcopenshell.api.sequence.assign_sequence(model,
    relating_process=formwork, related_process=reinforcement)

# Now typically there would be no lag time between formwork and
# reinforcement, but let's pretend that we had to allow 1 day gap
# for whatever reason.
lag = ifcopenshell.api.sequence.assign_lag_time(model, rel_sequence=sequence, lag_value="P1D")

# Or, let's make it 2 days instead.
ifcopenshell.api.sequence.edit_lag_time(model, lag_time=lag, attributes={"LagValue": "P2D"})

ifcopenshell.api.sequence.edit_recurrence_pattern(file: ifcopenshell.file, recurrence_pattern: ifcopenshell.entity_instance, attributes: dict[str, Any]) → None¶

Edits the attributes of an IfcRecurrencePattern

For more information about the attributes and data types of an IfcRecurrencePattern, consult the IFC documentation.

Parameters:

recurrence_pattern (ifcopenshell.entity_instance) – The IfcRecurrencePattern entity you want to edit
attributes (dict) – a dictionary of attribute names and values.

Returns:

None

Return type:

None

Example:

# Let's create a new calendar.
calendar = ifcopenshell.api.sequence.add_work_calendar(model)

# Let's start defining the times that we work during the week.
work_time = ifcopenshell.api.sequence.add_work_time(model,
    work_calendar=calendar, time_type="WorkingTimes")

# We create a weekly recurrence
pattern = ifcopenshell.api.sequence.assign_recurrence_pattern(model,
    parent=work_time, recurrence_type="WEEKLY")

# State that we work from weekdays 1 to 5 (i.e. Monday to Friday)
ifcopenshell.api.sequence.edit_recurrence_pattern(model,
    recurrence_pattern=pattern, attributes={"WeekdayComponent": [1, 2, 3, 4, 5]})

ifcopenshell.api.sequence.edit_sequence(file: ifcopenshell.file, rel_sequence: ifcopenshell.entity_instance, attributes: dict[str, Any]) → None¶

Edits the attributes of an IfcRelSequence

For more information about the attributes and data types of an IfcRelSequence, consult the IFC documentation.

Parameters:

rel_sequence (ifcopenshell.entity_instance) – The IfcRelSequence entity you want to edit
attributes (dict) – a dictionary of attribute names and values.

Returns:

None

Return type:

None

Example:

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

# Let's imagine a root construction task
construction = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Construction", identification="C")

# Let's imagine we're building 2 zones, one after another.
zone1 = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Zone 1", identification="C.1")
zone2 = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Zone 2", identification="C.2")

# Zone 1 finishes, then zone 2 starts.
sequence = ifcopenshell.api.sequence.assign_sequence(model,
    relating_process=zone1, related_process=zone2)

# What if they both started at the same time?
ifcopenshell.api.sequence.edit_sequence(model,
    rel_sequence=sequence, attributes={"SequenceType": "START_START"})

ifcopenshell.api.sequence.edit_task(file: ifcopenshell.file, task: ifcopenshell.entity_instance, attributes: dict[str, Any]) → None¶

Edits the attributes of an IfcTask

For more information about the attributes and data types of an IfcTask, consult the IFC documentation.

Parameters:

task (ifcopenshell.entity_instance) – The IfcTask entity you want to edit
attributes (dict) – a dictionary of attribute names and values.

Returns:

None

Return type:

None

Example:

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

# Add a root task to represent the design milestones, and major
# project phases.
task = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Milestones", identification="A")

# Change the identification
ifcopenshell.api.sequence.edit_task(model, task=task, attributes={"Identification": "M"})

ifcopenshell.api.sequence.edit_task_time(file: ifcopenshell.file, task_time: ifcopenshell.entity_instance, attributes: dict[str, Any]) → None¶

Edits the attributes of an IfcTaskTime

For more information about the attributes and data types of an IfcTaskTime, consult the IFC documentation.

Parameters:

task_time (ifcopenshell.entity_instance) – The IfcTaskTime entity you want to edit
attributes (dict) – a dictionary of attribute names and values.

Returns:

None

Return type:

None

Example:

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

# Create a task to do formwork
task = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Formwork", identification="A")

# Let's say it takes 2 days and starts on the 1st of January, 2000
time = ifcopenshell.api.sequence.add_task_time(model, task=formwork)
ifcopenshell.api.sequence.edit_task_time(model,
    task_time=time, attributes={"ScheduleStart": "2000-01-01", "ScheduleDuration": "P2D"})

ifcopenshell.api.sequence.edit_work_calendar(file: ifcopenshell.file, work_calendar: ifcopenshell.entity_instance, attributes: dict[str, Any]) → None¶

Edits the attributes of an IfcWorkCalendar

For more information about the attributes and data types of an IfcWorkCalendar, consult the IFC documentation.

Parameters:

work_calendar (ifcopenshell.entity_instance) – The IfcWorkCalendar entity you want to edit
attributes (dict) – a dictionary of attribute names and values.

Returns:

None

Return type:

None

Example:

# Let's create a new calendar.
calendar = ifcopenshell.api.sequence.add_work_calendar(model, name="5 Day Week")

# Let's give it a description
ifcopenshell.api.sequence.edit_work_calendar(model,
    work_calendar=calendar, attributes={"Description": "Monday to Friday 8 hour days"})

ifcopenshell.api.sequence.edit_work_plan(file: ifcopenshell.file, work_plan: ifcopenshell.entity_instance, attributes: dict[str, Any]) → None¶

Edits the attributes of an IfcWorkPlan

For more information about the attributes and data types of an IfcWorkPlan, consult the IFC documentation.

Parameters:

work_plan (ifcopenshell.entity_instance) – The IfcWorkPlan entity you want to edit
attributes (dict) – a dictionary of attribute names and values.

Returns:

None

Return type:

None

Example:

# This will hold all our construction schedules
work_plan = ifcopenshell.api.sequence.add_work_plan(model, name="Construction")

# Let's give it a description
ifcopenshell.api.sequence.edit_work_plan(model,
    work_plan=work_plan, attributes={"Description": "Construction of phase 1"})

ifcopenshell.api.sequence.edit_work_schedule(file: ifcopenshell.file, work_schedule: ifcopenshell.entity_instance, attributes: dict[str, Any]) → None¶

Edits the attributes of an IfcWorkSchedule

For more information about the attributes and data types of an IfcWorkSchedule, consult the IFC documentation.

Parameters:

work_schedule (ifcopenshell.entity_instance) – The IfcWorkSchedule entity you want to edit
attributes (dict) – a dictionary of attribute names and values.

Returns:

None

Return type:

None

Example:

# This will hold all our construction schedules
work_plan = ifcopenshell.api.sequence.add_work_plan(model, name="Construction")

# Let's imagine this is one of our schedules in our work plan.
schedule = ifcopenshell.api.sequence.add_work_schedule(model,
    name="Construction Schedule A", work_plan=work_plan)

# Let's give it a description
ifcopenshell.api.sequence.edit_work_schedule(model,
    work_schedule=work_schedule, attributes={"Description": "3 crane design option"})

ifcopenshell.api.sequence.edit_work_time(file: ifcopenshell.file, work_time: ifcopenshell.entity_instance, attributes: dict[str, Any]) → None¶

Edits the attributes of an IfcWorkTime

For more information about the attributes and data types of an IfcWorkTime, consult the IFC documentation.

Parameters:

work_time (ifcopenshell.entity_instance) – The IfcWorkTime entity you want to edit
attributes (dict) – a dictionary of attribute names and values.

Returns:

None

Return type:

None

Example:

# Let's create a new calendar.
calendar = ifcopenshell.api.sequence.add_work_calendar(model)

# Let's start defining the times that we work during the week.
work_time = ifcopenshell.api.sequence.add_work_time(model,
    work_calendar=calendar, time_type="WorkingTimes")

# If we don't specify any recurring time periods in our work time,
# we need to specify a start and end date of the work time. It
# starts at 0:00 on the start date and 24:00 at the end date.
ifcopenshell.api.sequence.edit_work_time(model,
    work_time=work_time, attributes={"StartDate": "2000-01-01", "FinishDate": "2000-01-02"})

ifcopenshell.api.sequence.remove_task(file: ifcopenshell.file, task: ifcopenshell.entity_instance) → None¶

Removes a task

All subtasks are also removed recursively. Any relationships such as sequences or controls are also removed.

Parameters:: task (ifcopenshell.entity_instance) – The IfcTask to remove.
Returns:: None
Return type:: None

Example:

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

# Add a root task to represent the design milestones, and major
# project phases.
ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Milestones", identification="A")
design = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Design", identification="B")
ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Construction", identification="C")

# Ah, let's delete the design section, who needs it anyway we'll
# just fix it on site.
ifcopenshell.api.sequence.remove_task(model, task=design)

ifcopenshell.api.sequence.remove_time_period(file: ifcopenshell.file, time_period: ifcopenshell.entity_instance) → None¶

Removes a time period

Parameters:: time_period (ifcopenshell.entity_instance) – The IfcTimePeriod to remove.
Returns:: None
Return type:: None

Example:

# Let's create a new calendar.
calendar = ifcopenshell.api.sequence.add_work_calendar(model)

# Let's start defining the times that we work during the week.
work_time = ifcopenshell.api.sequence.add_work_time(model,
    work_calendar=calendar, time_type="WorkingTimes")

# We create a weekly recurrence
pattern = ifcopenshell.api.sequence.assign_recurrence_pattern(model,
    parent=work_time, recurrence_type="WEEKLY")

# State that we work from weekdays 1 to 5 (i.e. Monday to Friday)
ifcopenshell.api.sequence.edit_recurrence_pattern(model,
    recurrence_pattern=pattern, attributes={"WeekdayComponent": [1, 2, 3, 4, 5]})

# The morning work session, lunch, then the afternoon work session.
morning = ifcopenshell.api.sequence.add_time_period(model,
    recurrence_pattern=pattern, start_time="09:00", end_time="12:00")
afternoon = ifcopenshell.api.sequence.add_time_period(model,
    recurrence_pattern=pattern, start_time="13:00", end_time="17:00")

# Let's take the afternoon off!
ifcopenshell.api.sequence.remove_time_period(model, time_period=afternoon)

ifcopenshell.api.sequence.remove_work_calendar(file: ifcopenshell.file, work_calendar: ifcopenshell.entity_instance) → None¶

Removes a work calendar

All relationships are also removed, such as if a task is set to use that calendar.

Parameters:: work_calendar (ifcopenshell.entity_instance) – The IfcWorkCalendar to remove
Returns:: None
Return type:: None

Example:

# Let's create a new calendar.
calendar = ifcopenshell.api.sequence.add_work_calendar(model, name="5 Day Week")

# And remove it immediately
ifcopenshell.api.sequence.remove_work_calendar(model, work_calendar=calendar)

ifcopenshell.api.sequence.remove_work_plan(file: ifcopenshell.file, work_plan: ifcopenshell.entity_instance) → None¶

Removes a work plan

Note that schedules that are grouped under the work plan are not removed.

Parameters:: work_plan (ifcopenshell.entity_instance) – The IfcWorkPlan to remove.
Returns:: None
Return type:: None

Example:

# This will hold all our construction schedules
work_plan = ifcopenshell.api.sequence.add_work_plan(model, name="Construction")

# And remove it immediately
ifcopenshell.api.sequence.remove_work_plan(model, work_plan=work_plan)

ifcopenshell.api.sequence.remove_work_schedule(file: ifcopenshell.file, work_schedule: ifcopenshell.entity_instance) → None¶

Removes a work schedule

All tasks in the work schedule are also removed recursively.

Parameters:: work_schedule (ifcopenshell.entity_instance) – The IfcWorkSchedule to remove.
Returns:: None
Return type:: None

Example:

# This will hold all our construction schedules
work_plan = ifcopenshell.api.sequence.add_work_plan(model, name="Construction")

# Let's imagine this is one of our schedules in our work plan.
schedule = ifcopenshell.api.sequence.add_work_schedule(model,
    name="Construction Schedule A", work_plan=work_plan)

# And remove it immediately
ifcopenshell.api.sequence.remove_work_schedule(model, work_schedule=schedule)

ifcopenshell.api.sequence.remove_work_time(file: ifcopenshell.file, work_time: ifcopenshell.entity_instance) → None¶

Removes a work time

Parameters:: work_time (ifcopenshell.entity_instance) – The IfcWorkTime to remove.
Returns:: None
Return type:: None

Example:

# Let's create a new calendar.
calendar = ifcopenshell.api.sequence.add_work_calendar(model)

# Let's start defining the times that we work during the week.
work_time = ifcopenshell.api.sequence.add_work_time(model,
    work_calendar=calendar, time_type="WorkingTimes")

# And remove it immediately
ifcopenshell.api.sequence.remove_work_time(model, work_time=work_time)

ifcopenshell.api.sequence.unassign_lag_time(file: ifcopenshell.file, rel_sequence: ifcopenshell.entity_instance) → None¶

Removes any lag time in a sequence

The schedule is cascaded afterwards.

Parameters:: rel_sequence (ifcopenshell.entity_instance) – The sequence to remove the lag time from.
Returns:: None
Return type:: None

Example:

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

# Let's imagine a root construction task
construction = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Construction", identification="C")

# Let's imagine we're building 2 zones, one after another.
zone1 = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Zone 1", identification="C.1")
zone2 = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Zone 2", identification="C.2")

# Zone 1 finishes, then zone 2 starts.
sequence = ifcopenshell.api.sequence.assign_sequence(model,
    relating_process=zone1, related_process=zone2)

# What if you had to wait 1 week before you could start zone 2?
ifcopenshell.api.sequence.assign_lag_time(model, rel_sequence=sequence, lag_value="P1W")

# What if you didn't?
ifcopenshell.api.sequence.unassign_lag_time(model, rel_sequence=sequence)

ifcopenshell.api.sequence.unassign_process(file: ifcopenshell.file, relating_process: ifcopenshell.entity_instance, related_object: ifcopenshell.entity_instance) → None¶

Unassigns a process and object relationship

See ifcopenshell.api.sequence.assign_process for details.

Parameters:

relating_process (ifcopenshell.entity_instance) – The IfcTask in the relationship.
related_object (ifcopenshell.entity_instance) – The related object.

Returns:

None

Return type:

None

Example:

# Let's imagine we are creating a construction schedule. All tasks
# need to be part of a work schedule.
schedule = ifcopenshell.api.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.sequence.add_task(model,
    work_schedule=schedule, name="Demolish existing", identification="A", predefined_type="DEMOLITION")

# Let's say we have a wall somewhere.
wall = ifcopenshell.api.root.create_entity(model, ifc_class="IfcWall")

# Let's demolish that wall!
ifcopenshell.api.sequence.assign_process(model, relating_process=task, related_object=wall)

# Change our mind.
ifcopenshell.api.sequence.unassign_process(model, relating_process=task, related_object=wall)

ifcopenshell.api.sequence.unassign_product(file: ifcopenshell.file, relating_product: ifcopenshell.entity_instance, related_object: ifcopenshell.entity_instance) → None¶

Unassigns a product and object relationship

See ifcopenshell.api.sequence.assign_product for details.

Parameters:

relating_product (ifcopenshell.entity_instance) – The IfcProduct in the relationship.
related_object (ifcopenshell.entity_instance) – The IfcTask in the relationship.

Returns:

None

Return type:

None

Example:

# Let's imagine we are creating a construction schedule. All tasks
# need to be part of a work schedule.
schedule = ifcopenshell.api.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.sequence.add_task(model,
    work_schedule=schedule, name="Build wall", identification="A", predefined_type="CONSTRUCTION")

# Let's say we have a wall somewhere.
wall = ifcopenshell.api.root.create_entity(model, ifc_class="IfcWall")

# Let's construct that wall!
ifcopenshell.api.sequence.assign_product(relating_product=wall, related_object=task)

# Change our mind.
ifcopenshell.api.sequence.unassign_product(relating_product=wall, related_object=task)

ifcopenshell.api.sequence.unassign_recurrence_pattern(file: ifcopenshell.file, recurrence_pattern: ifcopenshell.entity_instance) → None¶

Unassigns a recurrence pattern

Note that a recurring task time must have a recurrence pattern, so if you remove it, be sure to clean up after this API call (e.g. remove IfcTaskTimeRecurring entity or assign a different recurrence patern to it or replace IfcTaskTimeRecurring with IfcTaskTime).

Parameters:: recurrence_pattern (ifcopenshell.entity_instance) – The IfcRecurrencePattern to remove.
Returns:: None
Return type:: None

Example:

# Let's create a new calendar.
calendar = ifcopenshell.api.sequence.add_work_calendar(model)

# Let's start defining the times that we work during the week.
work_time = ifcopenshell.api.sequence.add_work_time(model,
    work_calendar=calendar, time_type="WorkingTimes")

# We create a weekly recurrence
pattern = ifcopenshell.api.sequence.assign_recurrence_pattern(model,
    parent=work_time, recurrence_type="WEEKLY")

# Change our mind, let's just maintain it whenever we feel like it.
ifcopenshell.api.sequence.unassign_recurrence_pattern(recurrence_pattern=pattern)

ifcopenshell.api.sequence.unassign_sequence(file: ifcopenshell.file, relating_process: ifcopenshell.entity_instance, related_process: ifcopenshell.entity_instance) → None¶

Removes a sequence relationship between tasks

Parameters:

relating_process (ifcopenshell.entity_instance) – The previous / predecessor task.
related_process (ifcopenshell.entity_instance) – The next / successor task.

Returns:

None

Return type:

None

Example:

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

# Let's imagine a root construction task
construction = ifcopenshell.api.sequence.add_task(model,
    work_schedule=schedule, name="Construction", identification="C")

# Let's imagine we're building 2 zones, one after another.
zone1 = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Zone 1", identification="C.1")
zone2 = ifcopenshell.api.sequence.add_task(model,
    parent_task=construction, name="Zone 2", identification="C.2")

# Zone 1 finishes, then zone 2 starts.
ifcopenshell.api.sequence.assign_sequence(model, relating_process=zone1, related_process=zone2)

# Let's make them unrelated
ifcopenshell.api.sequence.unassign_sequence(model,
    relating_process=zone1, related_process=zone2)

ifcopenshell.api.sequence¶

Submodules¶

Package Contents¶

`ifcopenshell.api.sequence`¶