177 lines
7.8 KiB
Python
177 lines
7.8 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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from typing import Union
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import ifcopenshell
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import ifcopenshell.api.aggregate
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import ifcopenshell.api.geometry
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import ifcopenshell.api.owner
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import ifcopenshell.guid
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import ifcopenshell.util.element
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import ifcopenshell.util.placement
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def assign_container(
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file: ifcopenshell.file,
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products: list[ifcopenshell.entity_instance],
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relating_structure: ifcopenshell.entity_instance,
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) -> Union[ifcopenshell.entity_instance, None]:
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"""Assigns products to be contained hierarchically in a space
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All physical IFC model elements must be part of a hierarchical tree
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called the "spatial decomposition", where large things are made up of
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smaller things. This tree always begins at an "IfcProject" and is then
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broken down using "decomposition" relationships, of which aggregation is
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the first relationship you will use. See
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ifcopenshell.api.aggregate.assign_object for more details about
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aggregation.
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The IfcProject will be "decomposed" into spatial structure elements.
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These are virtual spaces like stes, buildings, storeys, and spaces (i.e.
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rooms). You can't physically touch these spaces, but you can touch the
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products contained within these spaces.
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To state that a product is contained in a space, you will use a
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"containment" relationship. Containment is a very common relationship
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used to create the hierarchical spatial decomposition tree. For example,
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you might say that "This wall is on the third building storey", or "this
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table is in the living room space".
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The distinguishing factor between aggregation and containment is that
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aggregation occurs between objects of the same type (e.g. a large space
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is made up of smaller spaces), whereas containment is between two
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different types: explicitly saying that a physical product exists within
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a virtual space.
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Containment is critical in construction management, to know which
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objects are in which spaces, as often you would divide your construction
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schedule into storey by storey, or zone by zone. Containment is also
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critical in facility management, as it indicates through which space
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equipment may be accessed for maintenance purposes.
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As a product may only have a single location in the "spatial
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decomposition" tree, assigning an aggregate relationship will remove any
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previous aggregation, containment, or nesting relationships it may have.
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:param products: A list of physical IfcElements existing in the space.
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:param relating_structure: The IfcSpatialStructureElement element, such
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as IfcBuilding, IfcBuildingStorey, or IfcSpace that the element
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exists in.
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:return: The IfcRelContainedInSpatialStructure relationship instance
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or `None` if `products` was empty list.
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Example:
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.. code:: python
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project = ifcopenshell.api.root.create_entity(model, ifc_class="IfcProject")
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site = ifcopenshell.api.root.create_entity(model, ifc_class="IfcSite")
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building = ifcopenshell.api.root.create_entity(model, ifc_class="IfcBuilding")
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storey = ifcopenshell.api.root.create_entity(model, ifc_class="IfcBuildingStorey")
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space = ifcopenshell.api.root.create_entity(model, ifc_class="IfcSpace")
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# The project contains a site (note that project aggregation is a special case in IFC)
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ifcopenshell.api.aggregate.assign_object(model, products=[site], relating_object=project)
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# The site has a building, the building has a storey, and the storey has a space
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ifcopenshell.api.aggregate.assign_object(model, products=[building], relating_object=site)
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ifcopenshell.api.aggregate.assign_object(model, products=[storey], relating_object=building)
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ifcopenshell.api.aggregate.assign_object(model, products=[space], relating_object=storey)
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# Create a wall and furniture
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wall = ifcopenshell.api.root.create_entity(model, ifc_class="IfcWall")
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furniture = ifcopenshell.api.root.create_entity(model, ifc_class="IfcFurniture")
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# The wall is in the storey, and the furniture is in the space
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ifcopenshell.api.spatial.assign_container(model, products=[wall], relating_structure=storey)
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ifcopenshell.api.spatial.assign_container(model, products=[furniture], relating_structure=space)
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"""
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if not products:
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return
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products_set = set(products)
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structure_rel = next(iter(relating_structure.ContainsElements), None)
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previous_containers_rels: set[ifcopenshell.entity_instance] = set()
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products_without_containers: list[ifcopenshell.entity_instance] = []
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products_with_containers: list[ifcopenshell.entity_instance] = []
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# check if there is anything to change
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for product in products_set:
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product_rel = next(iter(product.ContainedInStructure), None)
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if product_rel is None:
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products_without_containers.append(product)
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continue
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# either structure_rel is None or product is part of different rel
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if product_rel != structure_rel:
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previous_containers_rels.add(product_rel)
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products_with_containers.append(product)
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# products with already assigned containers will be skipped
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products_to_change = products_without_containers + products_with_containers
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# nothing to change
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if not products_to_change:
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return structure_rel
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# can be either only aggregated or only contained at the same time
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ifcopenshell.api.aggregate.unassign_object(file, products=products_without_containers)
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# unassign elements from previous containers
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for rel in previous_containers_rels:
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related_elements = set(rel.RelatedElements) - products_set
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if related_elements:
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rel.RelatedElements = list(related_elements)
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ifcopenshell.api.owner.update_owner_history(file, element=rel)
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else:
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history = rel.OwnerHistory
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file.remove(rel)
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if history:
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ifcopenshell.util.element.remove_deep2(file, history)
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# assign elements to a new container
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if structure_rel:
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structure_rel.RelatedElements = list(set(structure_rel.RelatedElements) | products_set)
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ifcopenshell.api.owner.update_owner_history(file, element=structure_rel)
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else:
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structure_rel = file.create_entity(
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"IfcRelContainedInSpatialStructure",
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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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"RelatedElements": list(products_set),
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"RelatingStructure": relating_structure,
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}
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)
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# localize placement relative to a new container for affected products
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for product in products_to_change:
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placement = getattr(product, "ObjectPlacement", None)
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if placement and placement.is_a("IfcLocalPlacement"):
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ifcopenshell.api.geometry.edit_object_placement(
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file,
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product=product,
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matrix=ifcopenshell.util.placement.get_local_placement(product.ObjectPlacement),
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is_si=False,
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)
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return structure_rel
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