Capabilities and status

This page is deliberately conservative. It exists so that an engineer — or a coding agent — can scope work against what the code does, not against what the IFC schema contains or a crate name suggests.

Status vocabulary

Term	Meaning
Implemented	Executable behaviour with tests. Safe to build on.
Partial	A real vertical slice exists; named gaps return typed errors.
Scaffold	Module and crate ownership exist. No behaviour. Files are doc-comment placeholders that reserve a name so the architecture is reviewable.
Absent	Not present in the workspace at all. Not even a reserved name.

A scaffold crate compiles, publishes, and appears in the feature list. It does not read, write, or interpret the entities its module names refer to.

Workspace census

Generated from the source tree by scripts/sync-capabilities.py, not estimated. "Stub files" counts source files of twelve lines or fewer — the placeholder shape described above. scripts/gate.sh fails if these numbers drift from the code.

Crate	Source LOC	Files	Stub files	Test files	Status
ifc-geometry	31,395	103	3	34	Partial
ifc-structural	3,397	33	14	12	Implemented
ifc-style	3,322	31	0	5	Implemented
ifc-properties	3,119	30	14	3	Implemented
ifc-alignment	2,909	29	11	5	Partial
ifc-template-catalog	2,726	29	3	10	Implemented
ifc-resource	2,647	29	9	9	Partial
ifc-validate	2,493	23	0	2	Implemented
ifc-material	2,398	24	0	8	Implemented
ifc-classification	2,203	20	4	3	Implemented
ifc-model	2,083	25	5	10	Implemented
ifc-cost	2,001	16	0	2	Implemented
ifc-schedule	1,691	24	14	1	Implemented
ifc-systems	1,586	20	5	2	Implemented
ifc-georef	1,423	18	9	2	Partial
ifc-schema	1,306	11	4	4	Implemented
ifc-constraint	1,230	6	0	1	Implemented
ifc-spatial	1,122	9	1	9	Implemented
ifc-xml	1,045	6	0	3	Implemented
ifc-approval	915	5	0	1	Implemented
openbim-ifc	901	6	0	14	Implemented
ifc-author	729	8	3	3	Implemented
ifc-step	516	5	0	3	Implemented

0 of 23 crates are scaffolds.

They exist because the layering decision (see ADR 0005) prefers declaring the intended home of a domain up front over discovering it later, but they must never be mistaken for working code.

Core: model, codecs, schema

Capability	Status	Evidence
Entity graph with positional attributes	Implemented	ifc-model::Model
Round-trip of entities the build does not understand	Implemented	openbim-ifc/tests/costing_roundtrip.rs (runs with no domain crate compiled)
STEP (.ifc) read and write	Implemented	ifc-step; deterministic model order, finite scalar safeguards, generic syntax delegated to openbim-step
ifcXML read and write	Implemented	ifc-xml; explicit strict IFC4 ADD2 TC1 namespace profile and path-rich typed diagnostics; compatibility dialect is not claimed as generic XSD conformance
IFC-JSON	Absent	Would be a third Codec impl; no crate exists
EXPRESS schema metadata, subtype queries	Implemented	ifc-schema
GlobalId base-64 encode/decode	Implemented	ifc-model::guid
Spatial containment tree traversal	Implemented	ifc-spatial::SpatialTree; facade feature spatial. See below.
Objectified relationship traversal	Implemented	All 42 concrete IfcRel* families are read. Spatial composition, containment, coverings, space boundaries, element connection and interference, assignment, declaration and system service in ifc-spatial; association and definition in ifc-classification, ifc-material, ifc-properties, ifc-resource, ifc-approval and ifc-constraint; connectivity in ifc-systems and ifc-structural; sequencing in ifc-schedule and ifc-cost; feature attachment in the openbim-ifc reachability check. Slot positions are asserted against the shipped IFC2x3/IFC4/IFC4x3 schemas in ifc-spatial/tests/slot_layout.rs, and openbim-ifc/tests/relationship_census.rs fails if a family loses its reader.
Distribution systems, ports and connectivity	Implemented	ifc-systems reads systems and membership, ports through both IfcRelNests and the legacy IfcRelConnectsPortToElement, the connection network, flow roles and direction, zones with their WR1 membership rule, spatial containment vs referencing, and direction-aware upstream/downstream queries. Relationship-only: no geometry is read, so a geometry-free file still yields a full network.
Cost items, rates and rollups	Implemented	ifc-cost reads IfcCostItem nesting, IfcCostValue component trees with arithmetic operators, and totals a cost tree. Currencies are compared, never converted: a rollup mixing EUR and USD is refused. Typed drafts stage selected IFC4 values, items, schedules, nesting, and schedule assignments atomically.
Work schedules, tasks and sequencing	Implemented	ifc-schedule reads IfcWorkPlan/IfcWorkSchedule, IfcTask with IfcTaskTime, IfcRelSequence with signed lag, work calendars and events, and produces a deterministic execution order. Cycles report the offending path.
Transactional authoring	Implemented	ifc-model::Transaction stages structural edits, validates them against the projected end state, and applies them as a unit. A removal that would orphan a surviving reference is refused, as is a commit against a model whose revision moved since the transaction opened. ifc-model remains schema-agnostic; typed staging helpers live in domain crates, including classification, documents, libraries, materials, quantities, cost, style, structural, and resources.
Quantity authoring	Implemented	ifc-properties stages quantity writes onto a caller-owned transaction, so a takeoff spanning many elements lands atomically. The declared measure type is preserved on every write.
Schema validation	Implemented	ifc-validate checks references, required slots, aggregate shape, entity types, abstract instantiation, scalar forms and STRING(n) FIXED widths against the exact schema the file declares (IFC2x3 TC1, IFC4 ADD2 TC1, or IFC4X3 ADD2). Eighteen registered rule IDs cover ten native checks under a hard findings-storage cap, including external-reference identity, sequence endpoints, decomposition and assignment self-reference, material and path-connection priority bounds, and space-boundary physicality across all three concrete IfcRelSpaceBoundary subtypes. Aggregate bounds, arbitrary EXPRESS WHERE expressions, INVERSE semantics and other known gaps remain explicitly unsupported and reported; a clean report never implies full EXPRESS conformance.
Property sets and every property value family	Implemented	ifc-properties reads single, enumerated, bounded, list, table, reference and complex properties. The declared measure type (IfcLengthMeasure and friends) is retained, because it is the only statement of what a bare number means.
Occurrence/type property precedence	Implemented	An occurrence property set overrides a same-named set inherited from the object's type. The shadowed type set is kept, so a checker can explain why an effective value differs from the type default.
Quantities and unit resolution	Implemented	Simple and complex quantities, SI prefixes carried as exact decimal exponents, conversion-based and derived units. WR21 (unit matches quantity kind) and WR22 (non-negative value) breaches are reported; ifcopenshell.validate checks neither. Quantities are read as authored assertions and never computed from geometry.
Type index (ids_of_type, of_type)	Implemented	Model::ids_of_type, backed by index/type_index.rs
Reverse-reference index ("who references me")	Implemented	ifc-model::ReverseIndex, built on demand; records the attribute slot
Bounded graph traversal with cycle reports	Implemented	ifc-model::{depth_first, breadth_first, find_cycle} with Budget/Stop
Dangling-reference detection	Implemented	Model::dangling_references
Schema-checked entity construction (authoring)	Implemented	ifc-author::EntityBuilder; facade feature author. See below.

Authoring

Applications that generate IFC name attributes; the schema decides positions.

use ifc::EntityBuilder;                 // feature = "author"

let id = EntityBuilder::new(&schema, "IfcAnnotation")
    .text("GlobalId", "3vB2YO$MX4xv5uCqZZG05x")
    .text("Name", "Brandwand")
    .insert(&mut model)?;

Slot order comes from Schema::attributes, which returns inherited attributes first — the ordering positional STEP records depend on. IfcAnnotation gets seven slots because IFC4 declares seven, not because the caller counted.

Construction is refused, rather than silently accepted, for:

Failure	Example
Unknown entity	IfcAnnotaton (typo)
Unknown attribute	IfcAnnotation.RefLatitude (belongs to IfcSite)
Attribute set twice	two Name calls, instead of a silent overwrite
Required attribute unset	IfcAnnotation with no GlobalId
Declared-type mismatch	a string where IfcLengthMeasure is declared
Scalar/aggregate confusion	a scalar where LIST OF is declared
Malformed GlobalId	not 22 characters in IFC's base-64 alphabet

A refused build leaves the model untouched.

What this is not. WHERE rules, inverse attributes, uniqueness, and cross-entity consistency need a whole model rather than one entity; ifc-validate owns those. Value checking is deliberately permissive where a declared type cannot be resolved — see ADR 0007 for why authoring is a schema-layer concern and not a model-layer one.

Model::push remains public and unchecked, for the case where an application must write an entity the schema does not declare.

Spatial traversal

IFC stores no parent pointers: a wall does not name its storey, a relationship entity names both ends. ifc-spatial reads those relationships into a tree.

use ifc::{SpatialKind, SpatialTree};   // feature = "spatial"

let tree = SpatialTree::build(&model);

for storey in tree.of_kind(SpatialKind::Storey) {
    for element in tree.elements_of(storey.id) {
        // every element placed directly on this storey
    }
}

tree.container_of(wall);        // which storey is this wall on?
tree.ancestors(storey.id);      // storey -> building -> site -> project
tree.elements_recursive(root);  // everything beneath a container

The trap this closes. The two relationships that build the tree disagree about slot order — IfcRelAggregates puts the parent in slot 4, IfcRelContainedInSpatialStructure puts it in slot 5. Reading one like the other inverts containment silently. The constants are asserted against IFC2x3, IFC4 and IFC4x3 in ifc-spatial/tests/slot_layout.rs; see ADR 0008.

Real files, not the ideal shape. Omitted sites, elements hung directly off a building, duplicate storeys, relationships naming absent entities, and containment cycles are all handled and, where they are defects, reported through orphans() and dangling() rather than dropped. One corpus fixture turned out to use IfcRelAggregates exclusively with no containment relationship at all; that case is pinned in tests/real_files.rs.

What this is not. It reports what the file says and never rejects it — cardinality and WHERE rules belong to ifc-validate. It groups elements; it does not interpret their geometry or properties.

Construction resources

With facade feature resource, ifc-resource selects IFC4 from the model header and exposes borrowed views for labor, equipment, crew, construction material, construction product, and subcontract occurrences. It resolves authored IfcResourceTime, validates and queries IfcRelAssignsToResource including its authored RelatedObjectsType category constraint, and walks resource composition through IfcRelNests with authored order plus explicit cycle, multiple-parent, depth, and node failures. Selected records and relationships can be created through schema-checked transaction-staged drafts; they reject duplicate GlobalId values and cycle/second-parent creation before staging. See the construction-resource guide.

This is a partial, deliberately bounded profile covering IFC4 and IFC4X3. It does not level or schedule resources, calculate costs/durations/quantities, interpret calendars, or claim IFC2X3 support (the schema does not declare the entities this crate projects).

Geometry

ifc-geometry is the one substantial domain crate. It resolves IFC units, placements, profiles, and representation relationships, then lowers implemented families into the neutral axiolid-model DAG.

Representation-item lowering

The dispatcher keeps coverage as data so it is auditable from one table (ifc-geometry/src/lower/dispatch.rs):

Family	Status
IfcExtrudedAreaSolid	Implemented
IfcRevolvedAreaSolid	Implemented
IfcBooleanResult	Implemented
IfcBooleanClippingResult	Implemented
IfcMappedItem	Implemented
IfcFacetedBrep	Implemented
IfcFacetedBrepWithVoids	Implemented
IfcAdvancedBrep	Implemented
IfcAdvancedBrepWithVoids	Implemented
IfcHalfSpaceSolid	Implemented
IfcBoxedHalfSpace	Implemented
IfcPolygonalBoundedHalfSpace	Implemented
IfcTriangulatedFaceSet	Implemented
IfcPolygonalFaceSet	Implemented
IfcCsgSolid	Implemented
IfcSweptDiskSolid	Implemented
IfcSweptDiskSolidPolygonal	Implemented
IfcSurfaceCurveSweptAreaSolid	Implemented
IfcBlock	Implemented
IfcSphere	Implemented
IfcRightCircularCylinder	Implemented
IfcRightCircularCone	Implemented
IfcRectangularPyramid	Implemented
IfcBoundingBox	Implemented
IfcExtrudedAreaSolidTapered	Implemented
IfcRevolvedAreaSolidTapered	Implemented
IfcFixedReferenceSweptAreaSolid	Implemented
IfcSectionedSpine	Implemented
IfcShellBasedSurfaceModel	Implemented
IfcFaceBasedSurfaceModel	Implemented
IfcGeometricSet	Implemented
IfcGeometricCurveSet	Implemented
IfcLine	Implemented
IfcCircle	Implemented
IfcEllipse	Implemented
IfcPolyline	Implemented
IfcIndexedPolyCurve	Implemented
IfcCompositeCurve	Implemented
IfcCompositeCurveOnSurface	Implemented
IfcBoundaryCurve	Implemented
IfcOuterBoundaryCurve	Implemented
IfcTrimmedCurve	Implemented
IfcOffsetCurve2D	Implemented
IfcOffsetCurve3D	Implemented
IfcPcurve	Partial — 2 authored form(s) refused; see variants
IfcSurfaceCurve	Partial — 1 authored form(s) refused; see variants
IfcIntersectionCurve	Implemented
IfcSeamCurve	Implemented
IfcBSplineCurveWithKnots	Implemented
IfcRationalBSplineCurveWithKnots	Implemented
IfcPlane	Implemented
IfcCylindricalSurface	Implemented
IfcSphericalSurface	Implemented
IfcToroidalSurface	Implemented
IfcSurfaceOfLinearExtrusion	Implemented
IfcSurfaceOfRevolution	Implemented
IfcRectangularTrimmedSurface	Implemented
IfcCurveBoundedPlane	Implemented
IfcCurveBoundedSurface	Implemented
IfcBSplineSurfaceWithKnots	Implemented
IfcRationalBSplineSurfaceWithKnots	Implemented
IfcPointOnCurve	Implemented
IfcPointOnSurface	Implemented

Partially supported variants

Families marked Partial above lower some authored forms exactly and refuse others by name. This table is generated from the PARTIAL catalog in ifc-geometry/src/lower/dispatch.rs, and tests/lower_dispatch_corpus.rs drives the real lowering path for every row -- so a wrong disposition here fails CI rather than merely misinforming a reader.

Some of these refusals exist because the schema permits a combination the geometry cannot honour, rather than because the feature is unimplemented. Those are listed with their reasoning in Schema looseness.

Family	Variant	Status	Rationale
IfcPcurve	reference curve is an IfcPolyline	Admitted	an ordered 2D point sequence needs no evaluation
IfcPcurve	reference curve is an IfcIndexedPolyCurve with no explicit Segments, or only IfcLineIndex segments	Admitted	reads identically to a plain ordered point sequence
IfcPcurve	reference curve is an IfcLine, IfcCircle or IfcEllipse positioned by an IfcAxis2Placement2D	Admitted	defining values are read verbatim in the surface's own (u, v) domain with no unit conversion
IfcPcurve	reference conic positioned by an IfcAxis2Placement3D	Refused	a 3D placement's axis has no meaning in a 2D parameter domain; admitting it would require inventing a projection
IfcPcurve	reference curve is an IfcIndexedPolyCurve with an explicit IfcArcIndex segment	Admitted	a three-point arc composes exactly from a parameter-space circumcentre into Circle2 plus a Cartesian trim, mirroring the 3D path with no approximation
IfcPcurve	reference curve is an explicit-knot IfcBSplineCurveWithKnots or IfcRationalBSplineCurveWithKnots	Admitted	every field is dimensionless or a curve parameter; knots already pass through the 3D path unscaled, and control points are read as raw (u, v) pairs
IfcPcurve	reference curve is a trimmed or composite curve	Admitted	trim parameters and segments stay in the surface (u, v) domain, unscaled, so no dimensional contract is needed
IfcPcurve	reference curve is a convention-only IfcBSplineCurve	Refused	a base spline carries no authored knot vector to preserve
IfcSurfaceCurve	MasterRepresentation is Curve3D, PCurveS1, or PCurveS2 with the named side present	Admitted	each side pairs a surface with its own p-curve, so the neutral MasterRepresentation names S1 and S2 exactly
IfcSurfaceCurve	MasterRepresentation is PCurveS2 with only one associated p-curve	Refused	the master names a parametric side the curve does not have; the schema calls this inconsistent, so it is refused rather than resolved to the remaining p-curve

Coverage below is generated

The table above is derived from ifc-geometry/src/lower/dispatch.rs by scripts/sync-capabilities.py, and scripts/gate.sh fails when this page and that source disagree. It cannot drift from the code without breaking the build.

Unimplemented families return a typed GeometryError::Unsupported naming the source entity and the specific missing capability — never a panic, and never a silently substituted approximate shape.

Profile lowering

Swept solids reference a profile, so profile coverage bounds how much of a real model lowers. Steel sections carry their fillet radii, edge radii and flange slopes into the neutral model rather than being reduced to an outline, because a section without them has the wrong area and the wrong section modulus.

Profile family	Status
IfcArbitraryClosedProfileDef	Implemented
IfcArbitraryOpenProfileDef	Implemented
IfcArbitraryProfileDefWithVoids	Implemented
IfcAsymmetricIShapeProfileDef	Implemented
IfcCenterLineProfileDef	Implemented
IfcCircleHollowProfileDef	Implemented
IfcCircleProfileDef	Implemented
IfcCompositeProfileDef	Implemented
IfcCShapeProfileDef	Implemented
IfcDerivedProfileDef	Implemented
IfcEllipseProfileDef	Implemented
IfcIShapeProfileDef	Implemented
IfcLShapeProfileDef	Implemented
IfcMirroredProfileDef	Implemented
IfcRectangleHollowProfileDef	Implemented
IfcRectangleProfileDef	Implemented
IfcRoundedRectangleProfileDef	Implemented
IfcTShapeProfileDef	Implemented
IfcTrapeziumProfileDef	Implemented
IfcUShapeProfileDef	Implemented
IfcZShapeProfileDef	Implemented
IfcProfileDef	Refused — generic profile declaration carries no concrete geometry to lower

IfcArbitraryOpenProfileDef is implemented through the explicit lower_open_profile_node authored-path API. It is not an area profile and is therefore still refused when an extrusion or other area-based solid requests lower_profile.

Curves and placement

Capability	Status	Module
IfcPolyline, IfcIndexedPolyCurve	Implemented	exact line and three-point arc segments
IfcCircle, IfcEllipse	Implemented	curve/conic.rs
IfcLine	Implemented	curve/line.rs
IfcTrimmedCurve	Implemented	curve/trimmed.rs
IfcCompositeCurve	Implemented	curve/composite.rs
Convention-only IfcBSplineCurve	Partial	typed view only; lowering does not invent absent knots
IfcBSplineCurveWithKnots, IfcRationalBSplineCurveWithKnots	Implemented	curve/bspline.rs representation + exact neutral lowering
IfcOffsetCurve2D/3D	Implemented	curve/offset.rs
IfcPcurve, IfcSurfaceCurve, IfcIntersectionCurve	Partial	exact supported forms; typed refusal otherwise
IfcAxis2Placement2D/3D	Implemented	resource/placement.rs
IfcCartesianTransformationOperator*	Implemented	resource/operator.rs
Unit resolution (SI, conversion-based)	Implemented	units.rs

Curves lower in nested and curve-representation paths

lower/curve.rs lowers polylines/indexed poly-curves, conics, lines, trims, composites, offsets and surface-associated curves, plus explicit-knot polynomial/rational B-splines into the neutral graph. Convention-only base splines remain unsupported. Curves reach this lowerer through a sweep directrix, a surface boundary, a B-rep edge, or an IfcGeometricCurveSet member.

Bare curves are dispatch targets for Curve2D, Curve3D, and plan representations. Selection remains explicit: callers choose Body or Plan; a plan curve never silently replaces a body.

Explicit-knot surfaces

Capability	Status	Module
Convention-only IfcBSplineSurface	Partial	typed view only. Lowering requires an explicit knot vector, so IfcBSplineSurfaceWithKnots lowers and the convention-only parent form does not: deriving the implied knots would be inventing geometry the file did not state.

Representation selection

Two selectors, deliberately disagreeing:

use ifc::{select_shape_representation, select_plan_representation};

select_shape_representation(&model, wall)?;  // -> the Body   (3D viewer)
select_plan_representation(&model, wall)?;   // -> the FootPrint (drawing)

select_shape_representation prefers Body, then Facetation, then an unnamed representation, and refuses Axis/FootPrint so a 2D curve never silently replaces a solid.

select_plan_representation is its inverse. It prefers, in order:

1. a PLAN_IDENTIFIERS match inside a PLAN_VIEW sub-context — drawable geometry the author explicitly targeted at a plan;
2. otherwise the best PLAN_IDENTIFIERS match in any context: Plan, Annotation, FootPrint, Axis.

The two rules are intersected, not ordered. Authorial intent selects between drawable candidates; it does not make a bounding box drawable. ArchiCAD writes Box/BoundingBox representations inside PLAN_VIEW sub-contexts, so a context-first rule returns those boxes and never reaches the identifier list.

It returns None for a solid-only or box-only product. That is the honest answer, not a failure: deriving a plan from a solid requires sectioning, which this library does not do — see R9b/R10 on the roadmap.

Representation context

Capability	Status	Evidence
IfcGeometricRepresentationContext	Implemented	RepresentationContext; identifier, type, precision, placement
IfcGeometricRepresentationSubContext	Implemented	parent, target scale, target view
TargetView (PLAN_VIEW, MODEL_VIEW, ...)	Implemented	typed enum; unknown constants preserved, not flattened
Authoring a plan sub-context	Partial	constructible via EntityBuilder; no dedicated helper

use ifc::plan_contexts;

for context in plan_contexts(&model) {
    context.target_scale();          // Some(0.01) for 1:100
    context.precision(&model);       // inherited from the parent context
}

The * trap this closes. A sub-context redeclares six inherited attributes as DERIVED, and real files write them as *:

IFCGEOMETRICREPRESENTATIONSUBCONTEXT('Body','Model',*,*,*,*,#1,$,.MODEL_VIEW.,$)

* is not $ — it means "read this from my parent". Accessors that take &model (precision, world_coordinate_system, coordinate_space_dimension, true_north) walk ParentContext to resolve it. A consumer reading the slot directly gets the marker and loses the project's precision and placement. See ADR 0009.

Slot positions are asserted against IFC2x3, IFC4 and IFC4x3 in ifc-geometry/tests/context_slots.rs, including that the sub-context still inherits exactly six attributes — the off-by-six that would read TargetScale as the target view.

Presentation, annotation, and external references

These are the areas most relevant to drawing production and document/approval workflows. Presentation and annotation now have schema-resolved typed views and bounded transaction-staged authoring; rendering, drawing layout, and the approval resource remain outside the current domain contracts. External classification/document/library references have typed read/query/authoring coverage.

Entity / concept	Status	Note
IfcAnnotation	Implemented	Strict borrowed view and transaction-staged authoring; IFC4X3 PredefinedType remains version-conditional
IfcTextLiteral, IfcTextLiteralWithExtent	Implemented	Strict literal/placement/path/extent views and transaction-staged authoring
IfcAnnotationFillArea	Implemented	Type-checked outer/inner boundary views and transaction-staged authoring
IfcCurveStyle, IfcFillAreaStyle	Implemented	Schema-resolved curve/font/fill/hatch/tile views; no rendering claim
IfcSurfaceStyle and children	Implemented	RGB/factor, shading, rendering, lighting, refraction, and texture views; core surface graph authoring
IfcPresentationLayerAssignment	Implemented	Layer membership/style/visibility view and styled-layer authoring
IfcStyledItem	Implemented	Strict direct assignment view/writer and deterministic direct-over-layer resolution; IFC2x3 wrappers are explicit
IfcShapeRepresentation	Absent	Generic Representation view exists; the subtype does not
IfcGeometricRepresentationSubContext	Partial	Strict inherited view and plan-context query exist; authoring uses generic EntityBuilder, not a dedicated helper
IfcLibraryReference	Implemented	Strict borrowed view and transaction-staged authoring
IfcLibraryInformation	Implemented	Strict borrowed view and transaction-staged authoring
IfcRelAssociatesLibrary	Implemented	Deterministic object lookup and transaction-staged authoring
IfcExternalReference and IfcLibrarySelect	Implemented	Inherited fields are exposed by concrete views; select targets are type-checked
IfcExternalReferenceRelationship	Implemented	ifc-classification owns strict selected projections, deterministic lookup, and transaction-staged authoring
IfcApproval and selected approval relationships	Implemented	ifc-approval owns bounded IFC4 projections, queries, and transaction-staged authoring; the whole IfcApprovalResource schema is not claimed
IfcMetric, IfcObjective, and selected constraint relationships	Implemented	ifc-constraint preserves typed metric values and stages bounded IFC4 authoring without evaluating constraints
IfcClassificationReference	Implemented	Bounded hierarchy, explicit occurrence/type sources, and authoring

Because ifc-model round-trips entities structurally, every row above reads and re-exports without loss. The status distinguishes that baseline from typed interpretation and authoring; only rows marked implemented expose those domain contracts.

Explicit non-goals

• A CAD modelling kernel. Booleans, tessellation, and NURBS evaluation live in Axiolid or its providers.
• Rendering, drawing layout, or paper-space composition.
• Vendored ISO or buildingSMART schema payloads (the contributing guide).
• Any C++ in the dependency graph.

How to verify a claim on this page

1. Read the crate's public API and its tests/ directory.
2. Read the crate's PLAN.md — it records implementation state, unlike AGENTS.md which records stable contracts.
3. Run the gate: scripts/gate.sh.
4. For geometry coverage, read ifc-geometry/src/lower/dispatch.rs; the IMPLEMENTED and PLANNED constants are asserted by tests.