Upstream parity and drift

IFCX is an alpha draft developed in buildingSMART/IFC5-development. That repository publishes no license, so none of its files, examples or texts are copied here or published on this site. Conformance is shown instead by running this repository's code against a local checkout of upstream and recording the results: counts and failures, never content.

What is checked

• Round trip, validation, composition, layers, decoding, scenes: opt-in Rust tests (upstream_*) read every upstream example from the checkout named by IFCX_UPSTREAM_DIR.
• Parity: scripts/upstream-parity.sh bundles upstream's own TypeScript composition from the checkout at run time and compares its composed trees with this crate's, case by case, as JSON values. The cases and the known divergences are listed under Capabilities: upstream parity.
• glTF: scripts/gltf-validate.sh exports every example to GLB and runs the Khronos glTF validator on it.
• Imports: the ifcx.dev files the examples import are fetched into an offline mirror for the run, and their digests recorded.

Recorded results

These are the summary lines of the last accepted run, from scripts/upstream-drift/baseline.txt. Every number in Capabilities is pinned to the same revision.

Recorded against buildingSMART/IFC5-development 1a63082.

Check	What it runs	Recorded result
imports	Fetches every ifcx.dev file the examples import into an offline mirror (scripts/upstream-drift/fetch-imports.py)	7 URIs, 1 unavailable
		import https://ifcx.dev/@nlsfb/nlsfb@v1.ifcx sha256:22c3f74fa121296e
		import https://ifcx.dev/@openusd.org/usd@v1.ifcx sha256:ec9d50cd00e20c8b
		import https://ifcx.dev/@standards.buildingsmart.org/ifc/core/ifc@v5a.ifcx sha256:7ada4aea92eefd97
		import https://ifcx.dev/@standards.buildingsmart.org/ifc/core/prop@v5a.ifcx sha256:5bd444faf1b515b2
		import https://ifcx.dev/@standards.buildingsmart.org/ifc/ifc-infra/infra@v1.0.0.ifcx sha256:b1905b68ab20b943
		import https://ifcx.dev/@standards.buildingsmart.org/ifc/ifc-mat/ifc-mat@v1.0.0.ifcx sha256:0bfecb9f32ce8f10
		import https://ifcx.dev/@standards.buildingsmart.org/ifc/ifc-mat/prop@v1.0.0.ifcx unavailable (HTTP 404)
round-trip	Reads and writes every example, comparing content (upstream_round_trip)	47 files, 0 failures
validation	Validates every example against its own and its imported schemas (upstream_validation)	47 files: 47 valid, 0 need imported schemas, 0 invalid
composition	Composes every example, alone or on top of its example folder (upstream_composition)	47 files: 35 compose alone, 12 on their folder, 0 fail
layers	Builds and validates every import stack against the mirror (upstream_layers)	37 stacks built (37 valid), 4 unresolved, 0 failures
		unresolved 4x https://ifcx.dev/@standards.buildingsmart.org/ifc/ifc-mat/prop@v1.0.0.ifcx
decode	Decodes every transform, mesh, curve, point cloud and presentation attribute (upstream_decode)	47 files: 41840 transforms; 1925 meshes (720241 triangles, 522435 vertices); 85 curve attributes (85 polylines, 9946 vertices, 0 unsupported); 0 null deletions; 0 failures
		47 files: point clouds pcd 2, array 4, base64 2 (102761 points, 4 coloured); visibility 62, diffuseColor 9366, opacity 458, gltf::material 2 (2 PBR); 0 failures
scene	Builds the render scene of every example (upstream_scene)	47 files: 26218 instances, 4181777 triangles, 9884 segments, 102761 points, 0 warnings
parity	Compares composed trees with upstream's TypeScript (scripts/upstream-parity.sh)	59 cases: 56 match, 3 known divergences, 0 differ
gltf	Exports fixtures and examples to GLB and runs the Khronos glTF validator (scripts/gltf-validate.sh)	51 files: 0 errors, 0 warnings, 16 infos, 0 hints

Drift

The draft keeps moving. Every Monday, and on demand, .github/workflows/upstream-drift.yml runs scripts/upstream-drift.sh against upstream's default branch and compares each summary line with the baseline above. A failed check or a changed line opens, or updates, the single open issue labelled upstream-drift, naming the upstream commit and linking the logs. The workflow is not part of CI and never runs on a push or pull request.

When the evidence changes on purpose, docs/capabilities.md and the baseline are updated together (./scripts/upstream-drift.sh --update-baseline), naming the new revision, and this page follows on the next cargo run -p xtask -- docs. Contributing describes how to triage a drift issue and reproduce it locally.