Schema querying

Schema declarations

IfcOpenShell can query the IFC schema itself without instantiating or loading an IFC dataset.

import ifcopenshell
ifc4 = ifcopenshell.schema_by_name("IFC4")

A schema definition is known as a declaration. You may loop through all declarations or retrieve a declaration by name. All declarations have a name.

for declaration in ifc4.declarations():
    print(declaration.name()) # 'IfcAbsorbedDoseMeasure', 'IfcAccelerationMeasure', 'IfcActionRequest', ...

ifcwall = ifc4.declaration_by_name("IfcWall")

You can check if an entity is abstract, and retrive both the supertype and subtypes of an entity:

print(ifcwall.is_abstract()) # False
print(ifcwall.supertype()) # <entity IfcBuildingElement>
print(ifcwall.subtypes()) # (<entity IfcWallElementedCase>, <entity IfcWallStandardCase>)

You can retrieve only the direct attributes of an entity, or all the direct attributes including inherited attributes, or inverse attributes:

print(ifcwall.attributes())
print(ifcwall.all_attributes())
print(ifcwall.all_inverse_attributes())

buildingSMART property set templates

For each IFC schema version, buildingSMART publishes built in property and quantity set templates for standardised properties. These define property names, property sets, data types, and which IFC class they are applicable to. You can query these templates.

import ifcopenshell.util.pset
templates = ifcopenshell.util.pset.PsetQto("IFC4")

To get just the names of applicable templates for an entity:

# ['Pset_EnvironmentalImpactIndicators', 'Pset_EnvironmentalImpactValues', 'Pset_WallCommon', 'Qto_WallBaseQuantities', ...]
print(templates.get_applicable_names("IfcWall"))

They may also be retrieved as an IfcPropertySetTemplate entity:

print(templates.get_applicable("IfcWall"))

A single template may be retrieved by name:

templates.get_by_name('Pset_WallCommon')

You may add your own IFC files containing pset template definitions:

my_pset_library = ifcopenshell.open('/path/to/library.ifc')
templates.templates.append(my_pset_library)