IfcOpenShell/src/ifcopenshell-python/ifcopenshell/api/aggregate/assign_object.py

# IfcOpenShell - IFC toolkit and geometry engine
# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
#
# This file is part of IfcOpenShell.
#
# IfcOpenShell is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# IfcOpenShell is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.

import ifcopenshell
import ifcopenshell.api
import ifcopenshell.util.element
import ifcopenshell.util.placement


class Usecase:
    def __init__(self, file, product=None, relating_object=None):
        """Assigns an object as an aggregate to a product

        Typically used when you want to describe how large spaces are made up of
        smaller spaces. For example large spatial elements (e.g. sites,
        buidings) can be made out of smaller spatial elements (e.g. storeys,
        spaces).

        The other common usecase is when larger physical products are made up of
        smaller physical products. For example, a stair might be made out of a
        flight, a landing, a railing and so on. Or a wall might be made out of
        stud members, and coverings.

        IFC placements follow a convention where the placement is relative to
        its parent in the spatial hierarchy. If your product has a placement,
        its placement will be recalculated to follow this convention.

        :param product: The part of the aggregate, typically an IfcElement or
            IfcSpatialStructureElement subclass
        :type product: ifcopenshell.entity_instance
        :param relating_object: The whole of the aggregate, typically an
            IfcElement or IfcSpatialStructureElement subclass
        :type relating_object: ifcopenshell.entity_instance
        :return: The IfcRelAggregate relationship instance
        :rtype: ifcopenshell.entity_instance.entity_instance

        Example::

            element = ifcopenshell.api.run("root.create_entity", model, ifc_class="IfcSite")
            subelement = ifcopenshell.api.run("root.create_entity", model, ifc_class="IfcBuilding")
            ifcopenshell.api.run("aggregate.assign_object", model, product=subelement, relating_object=element)
        """
        self.file = file
        self.settings = {
            "product": product,
            "relating_object": relating_object,
        }

    def execute(self):
        decomposes = None
        if self.settings["product"].Decomposes:
            decomposes = self.settings["product"].Decomposes[0]

        is_decomposed_by = None
        for rel in self.settings["relating_object"].IsDecomposedBy:
            if rel.is_a("IfcRelAggregates"):
                is_decomposed_by = rel
                break

        if decomposes and decomposes == is_decomposed_by:
            return

        container = ifcopenshell.util.element.get_container(self.settings["product"], should_get_direct=True)
        if container:
            ifcopenshell.api.run("spatial.remove_container", self.file, product=self.settings["product"])

        if decomposes:
            related_objects = list(decomposes.RelatedObjects)
            related_objects.remove(self.settings["product"])
            if related_objects:
                decomposes.RelatedObjects = related_objects
                ifcopenshell.api.run("owner.update_owner_history", self.file, **{"element": decomposes})
            else:
                self.file.remove(decomposes)

        if is_decomposed_by:
            related_objects = set(is_decomposed_by.RelatedObjects)
            related_objects.add(self.settings["product"])
            is_decomposed_by.RelatedObjects = list(related_objects)
            ifcopenshell.api.run("owner.update_owner_history", self.file, **{"element": is_decomposed_by})
        else:
            is_decomposed_by = self.file.create_entity(
                "IfcRelAggregates",
                **{
                    "GlobalId": ifcopenshell.guid.new(),
                    "OwnerHistory": ifcopenshell.api.run("owner.create_owner_history", self.file),
                    "RelatedObjects": [self.settings["product"]],
                    "RelatingObject": self.settings["relating_object"],
                }
            )

        placement = getattr(self.settings["product"], "ObjectPlacement", None)
        if placement and placement.is_a("IfcLocalPlacement"):
            ifcopenshell.api.run(
                "geometry.edit_object_placement",
                self.file,
                product=self.settings["product"],
                matrix=ifcopenshell.util.placement.get_local_placement(self.settings["product"].ObjectPlacement),
                is_si=False,
            )

        return is_decomposed_by