Inspecting a structural-analysis model

This scenario reads an IFC structural-analysis exchange, inventories analytical members and actions, follows their relationships, and inspects authored loads without invoking a solver.

What the crate provides

Enable the facade feature:

openbim-ifc = { version = "0.1", features = ["structural"] }

Then build a schema-resolved borrowed view:

use ifc::{Codec, StepCodec};
use ifc::structural::StructuralView;

let model = StepCodec.read_bytes(&std::fs::read("analysis.ifc")?)?;
let structural = StructuralView::for_model(&model)?;

for id in model.ids_of_type("IFCSTRUCTURALANALYSISMODEL") {
    let analysis = structural.analysis_model(*id)?;
    println!("{:?}: {:?}", analysis.id(), analysis.name()?);

    for item in structural.analysis_items(*id)? {
        println!("assigned analytical object: {:?}", item);
    }
}
# Ok::<(), Box<dyn std::error::Error>>(())

for_model accepts exactly one canonical IFC2X3, IFC4, or IFC4X3 schema token. Unknown, missing, or ambiguous headers are errors rather than an IFC4 fallback.

Implemented semantics

The bounded view currently covers:

• IfcStructuralAnalysisModel, load groups, and result-group metadata;
• curve/surface analytical members, distinct varying-member subtypes, and point/curve/surface connections;
• typed boundary stiffness selectors plus failure/slippage connection conditions;
• versioned point and curve/linear/surface/planar actions with compatible structural-load references;
• single, linear, planar, and temperature static-load values plus IFC4+ ordered load configurations with optional locations;
• point reactions across all versions, IFC4+ curve/surface reactions, and result-group assignment traversal;
• model assignments, member-to-connection relationships, and activity assignments;
• selected analysis-model, static-load, member, connection, point/linear/planar action, member-connection, and activity-assignment authoring through a caller- owned transaction.

References are checked before being returned. Missing records, dangling IDs, wrong target types, incompatible action/reaction-load families, invalid assignment-select members, self-referencing groups, duplicate SET or load- configuration location members, multiply attached structural activities, malformed aggregates, and required-value omissions produce typed StructuralError values. Relationship traversal preserves relation-record file order and each aggregate's declared member order. Duplicate SET links, non-finite/invalid authoring measures, removed projected references, and duplicate activity attachments are rejected before transaction staging.

Version drift is resolved by attribute name against the selected schema. Examples include IFC4X3 AxisDirection versus earlier Axis, IFC2X3 numeric boundary stiffness versus IFC4+ boolean-or-measure selectors, IFC2X3-only varying-surface thickness payloads, IFC2X3 temperature names with underscores, IFC2X3 action fields, and IFC4+ SharedPlacement.

What remains application work

This crate does not calculate structural behaviour. An application must still provide or integrate:

• geometry/section-property extraction and coordinate transforms;
• FEM or other discretization;
• material constitutive models, stiffness assembly, load combinations, and solving;
• computed displacement, force, stress, reaction, or code-check results;
• result authoring beyond the currently exposed result-group metadata.

Those capabilities must not be inferred from the presence of IfcStructural* records.

Why this is not ifc-resource

IFC construction resources describe labour, equipment, material/product capacity, consumption, time, cost, and allocation to construction processes. Structural-analysis entities describe idealized mechanics and analysis topology. A physical beam may have an analytical-member representation and require resources to fabricate or install, but those are distinct semantic relationships and remain separate crate boundaries.

Evidence

The contract is exercised by ifc-structural/tests/: cross-version layouts, strict references, typed condition and varying-member projections, action/load groups, relationship traversal, rejected authoring, atomic commit, and STEP write/read round-trip. Boundary stiffness values are preserved literally; the crate does not translate them into solver constraints.