Files
2026-05-31 10:17:09 +07:00

136 lines
5.7 KiB
Python

# 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.owner
import ifcopenshell.util.element
def unassign_material(file: ifcopenshell.file, products: list[ifcopenshell.entity_instance]) -> None:
"""Removes any material relationship with the list of products
A product can only have one material assigned to it, which is why it is
not necessary to specify the material to unassign. The material is not
removed, only the relationship is removed.
If the product does not have a material, nothing happens.
Unassigning a LayerSet or ProfileSet from the product type will also
remove all Usages of the set.
:param products: The list IfcProducts that may or may not have a material
:return: None
Example:
.. code:: python
concrete = ifcopenshell.api.material.add_material(model, name="CON01", category="concrete")
# Let's imagine a concrete bench made out of concrete.
bench_type = ifcopenshell.api.root.create_entity(model, ifc_class="IfcFurnitureType")
ifcopenshell.api.material.assign_material(model,
products=[bench_type], type="IfcMaterial", material=concrete)
# Let's change our mind and remove the concrete assignment. The
# concrete material still exists, but the bench is no longer made
# out of concrete now.
ifcopenshell.api.material.unassign_material(model, products=[bench_type])
"""
usecase = Usecase()
usecase.file = file
return usecase.execute(products)
class Usecase:
file: ifcopenshell.file
def execute(self, products: list[ifcopenshell.entity_instance]) -> None:
if not products:
return
self.products = set(products)
self.remove_material_usages_from_types()
self.unassign_materials()
def remove_material_usages_from_types(self) -> None:
# remove material usages from types
for product in self.products:
if not product.is_a("IfcTypeObject"):
continue
material = ifcopenshell.util.element.get_material(product)
if not material:
continue
if material.is_a() in ["IfcMaterialLayerSet", "IfcMaterialProfileSet"]:
# Remove set usages
# TODO: be more considerate and remove only usages
# associated with the set + product type, not all usages?
for inverse in self.file.get_inverse(material):
if self.file.schema == "IFC2X3":
if not inverse.is_a("IfcMaterialLayerSetUsage"):
continue
# in IFC2X3 there is no .AssociatedTo
for inverse2 in self.file.get_inverse(inverse):
if inverse2.is_a("IfcRelAssociatesMaterial"):
history = inverse2.OwnerHistory
self.file.remove(inverse2)
if history:
ifcopenshell.util.element.remove_deep2(self.file, history)
else:
if not inverse.is_a("IfcMaterialUsageDefinition"):
continue
for rel in inverse.AssociatedTo:
history = rel.OwnerHistory
self.file.remove(rel)
if history:
ifcopenshell.util.element.remove_deep2(self.file, history)
self.file.remove(inverse)
def unassign_materials(self) -> None:
associations: set[ifcopenshell.entity_instance] = set()
for product in self.products:
associations.update(product.HasAssociations)
# we ensure that `associations` won't have removed elements
# to avoid crash during `material_inverses.issubset(associations)`
while associations:
rel = next(iter(associations))
if not rel.is_a("IfcRelAssociatesMaterial"):
associations.remove(rel)
else:
material = rel.RelatingMaterial
related_objects = set(rel.RelatedObjects) - self.products
if material.is_a() in ["IfcMaterialLayerSetUsage", "IfcMaterialProfileSetUsage"]:
# Warning: this may leave the model in a non-compliant state.
material_inverses = set(self.file.get_inverse(material))
if material_inverses.issubset(associations) and not related_objects:
self.file.remove(material)
associations.remove(rel)
if not related_objects:
history = rel.OwnerHistory
self.file.remove(rel)
if history:
ifcopenshell.util.element.remove_deep2(self.file, history)
continue
rel.RelatedObjects = list(related_objects)
ifcopenshell.api.owner.update_owner_history(self.file, element=rel)