Python

openbim-ifc is the Python binding of the IFC core (openbim-ifc-py), published to PyPI as compiled wheels.

pip install openbim-ifc

The binding exposes the record model over STEP: parse, read and edit attributes, and write. Domain views such as property sets or the spatial tree (#123), ifcXML, validation and checked transactions (#244) are not bound yet; use the Rust crates for those.

Read, edit and write

from openbim_ifc import IfcModel, Text

model = IfcModel.parse(data)  # or IfcModel.open("model.ifc")
schema = model.schema  # "IFC4"

for wall in model.ids_of_type("IfcWall"):
    name = model.attribute(wall, 2)  # Text(value='Wall')
    model.set_attribute(wall, 2, Text(f"{name.value} (checked)"))

data = model.write()  # bytes, ready to save

Attribute values are frozen dataclasses, one per STEP form, so nothing is lost in a round trip: Null() is $, Derived() is *, Unknown() is .U. and is never mistaken for Bool(False). Python integers are unbounded, so 64-bit IFC integers need no special type.

Every failure raises openbim_ifc.IfcError, whose code is shared with the JavaScript and C bindings.

API

Generated from the openbim_ifc package source.

Member	Description
IfcModel()	An empty model.
IfcModel.parse(data: bytes) -> IfcModel	Parse a STEP (.ifc) file from its bytes.
IfcModel.open(path: Union[str, os.PathLike[str]], *, mapped: bool = False) -> IfcModel	Read a STEP (.ifc) file from disk.
model.write() -> bytes	Serialize as STEP bytes.
len(model) -> int	Number of entities.
model.schema: Optional[str]	The first FILE_SCHEMA token, e.g. "IFC4", or None.
model.diagnostics() -> List[str]	Non-fatal problems found while reading.
model.ids() -> List[int]	Every entity id, in file order.
model.ids_of_type(type_name: str) -> List[int]	Ids of every entity of exactly type_name (case-insensitive).
model.ids_of_type_including_subtypes(type_name: str) -> List[int]	Ids of type_name or any subtype, per the file's schema.
model.type_of(id: int) -> str	The upper-case type name of entity id.
model.attributes(id: int) -> List[Value]	Every attribute of entity id, in declaration order.
model.attribute(id: int, index: int) -> Value	Attribute index of entity id; Null past the end.
model.set_attribute(id: int, index: int, value: Value) -> Value	Set attribute index of entity id; returns the old value.
model.add(type_name: str, attributes: Iterable[Value]) -> int	Append an entity; returns its new id.
model.remove(id: int) -> None	Remove entity id, leaving references to it dangling.
model.dangling_references() -> List[Tuple[int, int]]	Every (from, to) pair where to does not exist.

Attribute values are frozen dataclasses in openbim_ifc (from openbim_ifc.values):

Value	Meaning
Null()	$ -- the attribute is not set.
Derived()	* -- derived in a supertype; distinct from $.
Bool(value: bool)	.T. or .F..
Unknown()	.U. -- the third logical state.
Integer(value: int)	An integer literal (64-bit).
Real(value: float)	A real literal; must be finite.
Text(value: str)	A string.
Binary(value: str)	A binary literal, as its hex digits.
Enum(value: str)	An enumeration constant, without dots: Enum("ELEMENT").
Ref(id: int)	A reference to entity #id.
List(items: Tuple[Value, ...])	An aggregate (list, set, array or bag).
Typed(type: str, value: Value)	A typed wrapper such as IFCLENGTHMEASURE(2.5).