Validation

An IFC file that only its own writer can read is not an exchange format. brepjs-bim validates at four distances from the code that wrote the file.

Internal checkers

Five composable checks, each returning a severity-tagged report:

• checkReferentialIntegrity(model): every relationship points at an element that exists; containment, voids, fills, aggregation, and group membership all resolve.
• checkSchema(bytes): the exported file re-parses and passes structural schema checks.
• checkGeometryValidity(solids): the given element solids pass brepjs validity (closed, manifold, positive volume).
• checkRoundTrip(bytes): re-read an exported file and compare entity counts; losses are reported per type.
• checkGherkinRules(bytes): local implementations of the buildingSMART Validation Service's normative rules that touch this writer's vocabulary, currently IFC102 (no deprecated IFC4 entities or attributes), QTY001 (every Qto_* set validated against the official quantity table), and GRF003 (a facility model warns unless it declares a coordinate reference system).

toIfcValidated(model, meta) runs export plus the suite in one call:

import { toIfcValidated } from 'brepjs-bim';

const validated = await toIfcValidated(model, {
  applicationName: 'office-tool',
  applicationVersion: '1.0',
});
if (validated.ok) {
  const { bytes, report } = validated.value;
  // report.issues: severity-tagged findings from every gate
}

The complete official rule catalog

checkGherkinRules covers only the rules this writer's vocabulary can trip. The entire normative catalog is also runnable locally: scripts/setupGherkinRunner.sh in the package builds a pinned instance of the exact rule engine behind the buildingSMART Validation Service, and run-gherkin.sh model.ifc executes every ALB / GEM / GRF / IFC / OJT / PJS / PSE / QTY / SPS feature against a file in about a second. All three committed fixtures pass it completely: 950 scenarios, zero failures, zero undefined.

The distinction is worth keeping straight. toIfcValidated gives you a fast in-process subset on every export; the runner gives you the full catalog, the same rules the service would apply, before anything is uploaded.

The independent gate

Internal checks share code with the writer, so they cannot catch bugs the writer and reader agree on. The committed sample building is therefore validated by IfcOpenShell, a separate C++/Python IFC implementation sharing no code with web-ifc: EXPRESS schema + where-rules, spatial-structure presence, GlobalId validity and uniqueness, and geometry generation for every product. See VALIDATION.md in the package for the reproduction steps (two commands).

The semantic round-trip gate

The test suite additionally gates on semantic fidelity through a full source → IFC → import cycle: identity (GlobalIds), relationships (voids / fills / containment), property sets, spatial structure, and solid volumes within 0.5% all survive. This is what "round-trip" means here: not that a file parses, but that the model that comes back is the model that went out.

External tools

The buildingSMART Validation Service has been run against the fixtures, and its findings drove real writer fixes: an invalid scientific-real STEP token, then a semantic pass that surfaced six more defects (owner-history change action, person identification, unnamed type objects, an undefined curtain-wall enum literal, duplicated occurrence predefined types, and missing MethodOfMeasurement on quantity sets). All are fixed and regression-tested, and its rule catalog now runs locally as described above, so the service is confirmation rather than discovery.

Desktop imports (Solibri, Revit) remain unverified. Per-tool checklists and both fixtures are ready in the package's VALIDATION.md; results are recorded there as they land.