ifc-constraint

Bounded IFC4 metric, objective, and constraint relationships.

Status	Implemented
Latest release	0.3.0 (2026-09-29)
Registries	crates.io ifc-constraint
Via the facade	openbim-ifc feature constraint
API documentation	rustdoc · docs.rs
Source	crates/ifc-constraint/

Overview

Bounded metric, objective, and constraint-relationship semantics, read and written by attribute name in the model's declared release (IFC2X3, IFC4 or IFC4X3).

Values are projected and preserved; this crate does not evaluate compliance, formulas, references, tables, or time series.

Depends on

• ifc-model
• ifc-schema

Changes

Latest release, 0.3.0 (2026-09-29):

Added

• DateTimeInput: a creation time as IFC4/IFC4X3 IfcDateTime text or an IFC2X3 IfcDateTimeSelect record (From<&str>, From<EntityId>).
• ConstraintError::NotInSchema, StructuredValue, EntityNotInSchema, AuthoringNotInSchema and AuthoringValueType, and projections' release(). SchemaVersion is re-exported.

Changed (breaking)

• The constraint views read every attribute by name in the model's declared release (#212). They read IFC4 positions, types and SELECTs from every file. ConstraintView binds the header (IFC2X3, IFC4 or IFC4X3; none reads as IFC4) and a lookup refuses IFC4X1, IFC4X2, unknown and multiple schemas. An attribute the release does not declare is NotInSchema: IFC2X3 IfcMetric.ReferencePath, and IFC2X3 IfcObjective.LogicalAggregator, whose slot holds ResultValues, an IfcMetric, which was reported as a malformed operator. An IFC2X3 CreationTime record is StructuredValue with the record id instead of InvalidValue; IFC2X3's single BenchmarkValues metric is a one-element list; DataValue is checked against the release's own IfcMetricValueSelect and is required in IFC2X3. IFC4 and IFC4X3 answers are unchanged.

• create_metric, create_objective, relate_resource_constraint and create_reference bind the declared release and lay their records out by name (#212). In IFC2X3 a metric has ten attributes and requires DataValue, ReferencePath is AuthoringNotInSchema, an objective takes exactly one IfcMetric benchmark and no logical aggregator, text CreationTime is AuthoringValueType, and IfcResourceConstraintRelationship and IfcReference are EntityNotInSchema. Enumeration tokens are checked against the release's enumeration (IFC2X3 lacks, for example, INCLUDES and MODELVIEW). IFC4 and IFC4X3 records are unchanged.

• ConstraintBaseDraft::creation_time is Option<DateTimeInput>; the setter takes impl Into<DateTimeInput>, so .creation_time("…") still compiles.

• Metric::try_new, Objective::try_new, ResourceConstraintRelationship::try_new and ConstraintAssignment::try_new take the SchemaVersion to read against, refusing IFC4X1, IFC4X2 and an entity the release does not declare. ConstraintView::new is no longer const. A value for an attribute the release does not declare, which associate_constraint could not hit, is AuthoringNotInSchema rather than AuthoringInvalid.

• Every public draft is #[non_exhaustive], so struct literals no longer compile outside the crate. Each gains a constructor taking its required fields and one builder setter per other field, named after the field and taking the unwrapped value (.description("…") sets Some):

  • ConstraintBaseDraft::new(name, grade)
  • MetricDraft::new(base, benchmark)
  • ObjectiveDraft::new(base, qualifier)
  • ResourceConstraintDraft::new(relating_constraint, related_resources)
  • ConstraintAssociationDraft::new(global_id, related_objects, relating_constraint)
  • ReferenceDraft::new(), which now also derives Default

Changed

• Depends on ifc-schema with its default features named explicitly (every bundled release), now that the workspace dependency turns them off for the facade's per-release features (#112).
• A model whose header declares IFC4X1 or IFC4X2 is refused with the existing unsupported-schema error. ifc-schema now bundles both releases, but no layout here is verified against them, so they are never read as IFC4 or IFC4X3.

Full history: crates/ifc-constraint/CHANGELOG.md