131 lines
5.3 KiB
Python
131 lines
5.3 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
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import ifcopenshell.api.owner
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import ifcopenshell.guid
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def assign_process(
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file: ifcopenshell.file,
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relating_process: ifcopenshell.entity_instance,
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related_object: ifcopenshell.entity_instance,
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) -> ifcopenshell.entity_instance:
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"""Assigns an object as an input, control, or resource of a process
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Processes work using the ICOM (Input, Controls, Outputs, Mechanisms)
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paradigm in IFC. This process model is commonly used in modeling
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manufacturing functions.
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For example, processes (such as tasks) consume Inputs and transform them
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into Outputs. The process may only occur within the limits of Controls
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(e.g. cost items) and may require Mechanisms (ISO9000 calls them
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Mechanisms, whereas IFC calls them resources, such as raw materials,
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labour, or equipment).
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+----------+
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| Controls |
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+----------+
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V
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+--------+ +---------+ +---------+
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| Inputs | --> | Process | --> | Outputs |
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+--------+ +---------+ +---------+
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^
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+-----------+
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| Resources |
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+-----------+
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There are three main scenarios where an object may be related to a
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task: defining inputs, controls, and resources of a process.
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For inputs, a product (i.e. wall) may be defined as an input to a task,
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such as when the task is to demolish the wall (i.e. the wall is an
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input, and there is no output).
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For controls, a cost item may be defined as a control to a task.
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For resources, any construction resource may be assigned to a task.
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.. warning::
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This function creates an **Input** relationship
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(``IfcRelAssignsToProcess``), meaning the product is *consumed* or
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*operated on* by the task — the typical case is demolition or
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maintenance.
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If the task *constructs or installs* a product (e.g. erecting a wall
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or fitting a window), use :func:`assign_product` instead, which
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creates an **Output** relationship (``IfcRelAssignsToProduct``).
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:param relating_process: The IfcProcess (typically IfcTask) that the
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input, control, or resource is related to.
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:param related_object: The IfcProduct (for input), IfcCostItem (for
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control) or IfcConstructionResource (for resource).
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:return: The newly created IfcRelAssignsToProcess relationship
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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 create a demolition task. Note that the predefined type is
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# important to distinguish types of tasks.
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task = ifcopenshell.api.sequence.add_task(model,
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work_schedule=schedule, name="Demolish existing", identification="A", predefined_type="DEMOLITION")
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# Let's say we have a wall somewhere.
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wall = ifcopenshell.api.root.create_entity(model, ifc_class="IfcWall")
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# The wall is an INPUT to the demolition task (it will be consumed).
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ifcopenshell.api.sequence.assign_process(model, relating_process=task, related_object=wall)
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# For a construction task that BUILDS a wall, use assign_product instead:
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# build_task = ifcopenshell.api.sequence.add_task(model, ..., predefined_type="CONSTRUCTION")
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# ifcopenshell.api.sequence.assign_product(model, relating_product=wall, related_object=build_task)
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"""
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if related_object.HasAssignments:
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for assignment in related_object.HasAssignments:
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if assignment.is_a("IfcRelAssignsToProcess") and assignment.RelatingProcess == relating_process:
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return
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operates_on = None
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if relating_process.OperatesOn:
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operates_on = relating_process.OperatesOn[0]
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if operates_on:
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related_objects = list(operates_on.RelatedObjects)
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related_objects.append(related_object)
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operates_on.RelatedObjects = related_objects
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ifcopenshell.api.owner.update_owner_history(file, element=operates_on)
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else:
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operates_on = file.create_entity(
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"IfcRelAssignsToProcess",
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**{
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"GlobalId": ifcopenshell.guid.new(),
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"OwnerHistory": ifcopenshell.api.owner.create_owner_history(file),
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"RelatedObjects": [related_object],
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"RelatingProcess": relating_process,
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}
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)
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return operates_on
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