IFC Export & Import

Export

toIfc(model, meta) walks the model and returns IFC-SPF bytes.

import { toIfc } from 'brepjs-bim';

const result = await toIfc(model, {
  applicationName: 'office-tool',
  applicationVersion: '1.0',
  author: { givenName: 'Jane', familyName: 'Doe', email: 'jane@example.com' },
  organizationName: 'Example Ltd',
});
if (result.ok) await writeFile('model.ifc', result.value);

• Schema: IFC4 by default; pass ifcSchema: 'IFC4X3' to target the newer schema.
• Units: specs are millimeters; the writer emits SI metres (toIfcLengthM / toLengthMm convert explicitly).
• Owner history: author and organization metadata become a proper IfcOwnerHistory.
• Determinism: element GUIDs and local id counters are stable, and creationTimestamp defaults to the epoch, so re-exporting an unchanged model yields byte-identical content (modulo the timestamped FILE_NAME header line).

toIfcValidated runs export plus the validation suite in one call and returns the bytes together with the reports.

Import

fromIfc(bytes) parses an IFC file (via web-ifc) into an ImportedModel: elements with geometry, property sets, materials, and the spatial tree.

import { fromIfc, disposeImportedModel } from 'brepjs-bim';

const imported = await fromIfc(bytes);
if (imported.ok) {
  const model = imported.value;
  // model.elements, model.spatialTree, model.psets, ...
  disposeImportedModel(model);
}

Imported geometry pins kernel memory; call disposeImportedModel when done. For header-level inspection without geometry, SpfReader parses the STEP structure directly.

Round-tripping

Export → import → compare is a first-class operation, not a demo: checkRoundTrip(bytes) re-reads an exported file and reports entity counts and losses, and the test suite gates on semantic round-trip fidelity (identity, relationships, psets, containment, and volumes within 0.5%). If you build on the families layer, GlobalIds additionally survive source-level edits: they derive from key paths, not insertion order.