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BIM exchange guides

Foundations

What is IFC?

Understand model objects, geometry and properties, choose an IFC version, and set realistic expectations for an exchange.

Reading time
3 min
For
Anyone receiving, reviewing or specifying a BIM model
Learning objective
Explain what an IFC delivery contains and define the checks required before acceptance.

A shared description of a built asset

Industry Foundation Classes (IFC) is an open specification maintained by buildingSMART for exchanging building information modelling (BIM) data. It gives applications a shared way to describe a built asset and its associated information. An .ifc file is one representation of that data.

Architects, services engineers and asset managers may use different applications to review the same model elements. An IFC exchange allows each recipient to locate objects, inspect geometry and review the agreed information. Define the required review tasks before selecting export settings.

Model structure and information

An IFC property set groups named properties. Sets can belong to individual objects or their types, so a viewer may show information inherited from a type as well as information assigned to one occurrence. Inspect both when investigating a missing value.

Inspect table
InspectQuestion to askExample review action
Object identityCan we refer to the same object in another review?Record the IFC identifier and model revision.
Object meaningIs the object classified as intended?Compare a known door, slab and equipment item with the source.
GeometryIs the required shape present?Inspect openings, thin elements and curved components.
OrganizationCan the receiver navigate the delivery?Locate elements by building, storey or the agreed structure.
PropertiesAre required values readable and meaningful?Check a known asset identifier and a numeric value with its unit.

Use this table as a sample review plan. It does not mean every IFC file contains every item, or that a file with a convincing appearance is complete. Ask the sender to document exclusions and data unavailable in the source.

Agree the version with the recipient

IFC2x3, IFC4 and IFC4.3 are distinct published schema families. A draft specification is not an interchangeable substitute for a supported release. The official buildingSMART standards directory identifies publications and their status.

  • Record the exact schema, required exchange view or profile, and receiving application version.
  • Ask the recipient to test a representative sample before a full delivery. Include representative geometry and all required data.
  • Keep the agreed configuration with the delivery record. Repeat the sample test when the exporter, importer or requirements change.

Set expectations for conversion

Treat conversion as a transformation that needs checking. Do not assume a receiving application recreates the original editing tools, constraints or design history. If the next task needs native authoring behaviour, agree how the native model will also be supplied.

An export cannot establish the truth of information that was missing or incorrect in its source. When an item has only a mesh and a name, inferring a technical classification or performance value requires evidence and a responsible reviewer. Keep uncertain values distinguishable from approved data.

Five questions before accepting IFC

  • What decision or downstream task must this model support?
  • Which source revisions, disciplines and areas are included?
  • Which schema and import settings have both parties tested?
  • Which coordinates, properties and acceptance checks are required?
  • Who resolves rejected items and who approves the corrected delivery?

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