90 lines
4.3 KiB
Python
90 lines
4.3 KiB
Python
# IfcOpenShell - IFC toolkit and geometry engine
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# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
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#
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# This file is part of IfcOpenShell.
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#
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# IfcOpenShell is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# IfcOpenShell is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public License
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# along with IfcOpenShell. If not, see <http://www.gnu.org/licenses/>.
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import ifcopenshell.util.date
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def assign_lag_time(
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file: ifcopenshell.file, rel_sequence: ifcopenshell.entity_instance, lag_value: str, duration_type: str = "WORKTIME"
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) -> ifcopenshell.entity_instance:
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"""Assign a lag time to a sequence relationship between tasks
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A task sequence (e.g. finish to start) may optionally have a lag time
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defined. This is a fundamental concept in construction scheduling. The
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lag is defined as a duration, and the duration is typically either
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calendar based (i.e. follows the working times and holidays of the
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calendar) or elapsed time based (i.e. 24/7).
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A sequence may only have a single lag time defined. Negative lag times
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are allowed.
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:param rel_sequence: The IfcRelSequence to assign the lag time to.
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:param lag_value: An ISO standardised duration string.
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:param duration_type: Choose from WORKTIME for the associated
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calendar-based lag times (this is the most common scenario and is
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recommended as a default), or ELAPSEDTIME to not follow the
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calendar. You may also choose NOTDEFINED but the behaviour of this
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is unclear.
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:return: The newly created IfcLagTime
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Example:
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.. code:: python
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# Let's imagine we are creating a construction schedule. All tasks
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# need to be part of a work schedule.
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schedule = ifcopenshell.api.sequence.add_work_schedule(model, name="Construction Schedule A")
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# Let's imagine a root construction task
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construction = ifcopenshell.api.sequence.add_task(model,
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work_schedule=schedule, name="Construction", identification="C")
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# Let's imagine we're doing a typically formwork, reinforcement,
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# pour sequence. Let's start with the formwork. It'll take us 2
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# days.
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formwork = ifcopenshell.api.sequence.add_task(model,
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parent_task=construction, name="Formwork", identification="C.1")
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time = ifcopenshell.api.sequence.add_task_time(model, task=formwork)
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ifcopenshell.api.sequence.edit_task_time(model,
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task_time=time, attributes={"ScheduleStart": "2000-01-01", "ScheduleDuration": "P2D"})
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# Now let's do the reinforcement. It'll take us another 2 days.
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reinforcement = ifcopenshell.api.sequence.add_task(model,
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parent_task=construction, name="Reinforcement", identification="C.2")
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time = ifcopenshell.api.sequence.add_task_time(model, task=reinforcement)
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ifcopenshell.api.sequence.edit_task_time(model,
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task_time=time, attributes={"ScheduleStart": "2000-01-01", "ScheduleDuration": "P2D"})
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# Now let's say the formwork must finish before the reinforcement
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# can start. This is a typical finish to start relationship (FS).
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sequence = ifcopenshell.api.sequence.assign_sequence(model,
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relating_process=formwork, related_process=reinforcement)
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# Now typically there would be no lag time between formwork and
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# reinforcement, but let's pretend that we had to allow 1 day gap
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# for whatever reason.
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ifcopenshell.api.sequence.assign_lag_time(model, rel_sequence=sequence, lag_value="P1D")
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"""
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duration = file.create_entity("IfcDuration", ifcopenshell.util.date.datetime2ifc(lag_value, "IfcDuration"))
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lag_time = file.create_entity("IfcLagTime", DurationType=duration_type, LagValue=duration)
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if rel_sequence.is_a("IfcRelSequence"):
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if (current_lag_time := rel_sequence.TimeLag) and file.get_total_inverses(current_lag_time) == 1:
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file.remove(current_lag_time)
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rel_sequence.TimeLag = lag_time
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return lag_time
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