openbim-ifcx (Python)

Read, write, validate and compose IFC5 / IFCX files, and export them as GLB, from Python. A thin binding over the openbim-ifcx Rust crate, from the openbim-ifcx-py crate in openbimrs/ifcx: one abi3 wheel for CPython 3.9 and later.

The documentation has a Python guide and the API reference; the viewer shows an IFCX file in the browser.

Targets the ifcx_alpha draft of buildingSMART's IFC5. IFCX is still a moving draft; see the capabilities.

pip install openbim-ifcx

Example

from pathlib import Path
from openbim_ifcx import IfcxFile, compose, export_glb

model = Path("model.ifcx").read_bytes()
file = IfcxFile.parse(model)              # str or bytes
print(file.header["id"], file.node_count)

report = file.validate()
for f in report["failures"]:
    print(f["node"], f["attribute"], f["pointer"], f["kind"], f["message"])
Path("copy.ifcx").write_text(file.write())  # unchanged from the input

# Layers weakest first: the last layer's opinions win.
tree = compose([model, Path("overlay.ifcx").read_bytes()])
print(list(tree["children"]))              # the root nodes

# Any glTF viewer opens the result.
Path("model.glb").write_bytes(export_glb([model, Path("overlay.ifcx").read_bytes()]))

API

layers is one file or an iterable of files, weakest first. The package ships type hints (py.typed).

Lossless round trip. write() keeps key order, fields the draft does not define, null deletions and every number exactly as read.

Composed tree. compose returns the artificial root (path "") over every root node. Each node is {"path", "attributes", "children"}, the shape of upstream's PostCompositionNode, with children keyed by child name. Nodes shared through inheritance appear once per place they are used.

Imports. Without imports, imports are not resolved: the layers' schemas and data are concatenated in order, as upstream's Federate does. With imports (a mapping from the exact import uri to a file, possibly empty), the layers become the imports of a synthetic main layer, as upstream's ifcx compose command builds it, and every import must be supplied. integrity values are checked against the supplied bytes. In upstream order an import overrides the layer that imports it, and a later layer overrides both. Nothing is fetched from the network or the filesystem.

GLB export. export_glb writes the render scene of the composed tree: transformed, instanced meshes, lines and points with their materials, one glTF node per instance named by its IFCX path. The root node turns IFCX's Z-up into glTF's Y-up (y_up=False keeps Z-up) and carries the scene origin, so georeferenced models keep their coordinates (origin_on_root=False centres the model on the glTF origin instead). Geometry values that do not decode are left out.

Validation report. {"valid": bool, "failures": [...]}, each failure {"node", "attribute", "pointer", "kind", "message"}: the node path, the attribute id, an RFC 6901 pointer into the value ("" for the value itself), a stable kind such as missing-schema, type-mismatch, not-an-integer, not-an-option, missing-key, too-few-elements or too-many-elements, and a human message.

Errors

Every failure raises IfcxError with a stable code:

The codes are shared with the JavaScript binding (@openbim/ifcx); a code is never renamed or reused.

Threads

Parsing, composing, validating and GLB export release the GIL. An IfcxFile is immutable and can be shared between threads.

Build from source

uv venv && . .venv/bin/activate
uv pip install maturin
maturin develop --release     # or: scripts/check-python.sh to build + test

License

MIT, like the rest of openbimrs/ifcx.