IFC

IFC (Industry Foundation Classes) is a vendor-neutral and open standard that governs the exchange of building data within BIM projects. As a BIM exchange format, the IFC format is used to transfer the properties of digital building models between different software applications with as little data loss as possible.

As an essential foundation for cross-software collaboration in digital construction, IFC helps ensure that information remains consistent throughout the entire lifecycle of a building and is available to all project stakeholders.

An IFC file acts as a digital data container that provides structured and semantic information for Building Information Modeling (BIM). Compared with conventional CAD files, it does not only store geometric lines, but actual building components together with their context.

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The relevance of IFC

• Vendor independence: The openness of the standard prevents dependency on specific software providers, also known as vendor lock-in. This is particularly important for public sector projects.
• Collaborative workflows: Standardised building element classes and Property Sets make collaboration between different disciplines much easier.
• Transparency and validation: Structured attributes, such as material specifications or fire protection ratings, enable automated checks as well as precise quantity take-offs and documentation.
• Process chains: IFC connects phases such as Scan-to-BIM, planning and data handover to facility management systems (CAFM), supporting digitally assisted building operation.

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Why is IFC important?

• Open: Independent of individual software vendors and helps avoid vendor lock-in. Important for public sector projects.
• Collaboration: Standardised building element classes and Property Sets support cross-disciplinary workflows.
• Traceability: Structured attributes, such as materials and fire protection classes, enable automated checks, quantity take-offs and documentation.
• Continuity: Connects Scan-to-BIM, planning, handover to CAFM and digitally supported building operation.

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What information does an IFC file contain?

An IFC file can contain significantly more information than a conventional CAD file.

• Geometry: 3D shapes, coordinates, exact dimensions and the spatial orientation of all building elements.
• Classifications and types: Building components are defined precisely, for example as a wall, slab, column, window or door.
• Alphanumeric data: Additional properties such as material, fire protection class, manufacturer, costs or thermal conductivity, often stored in so-called Property Sets.
• Spatial hierarchy: The structural organisation of the building: project → site → building → storeys → rooms/building elements.
• Relationships and dependencies: Logical connections, for example which window sits in which wall or which door belongs to which room.

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How IFC works in practice

IFC is considered one of the most important standards in the open BIM approach.

Typical workflow:

• Model export: Planners create a model with building elements in their software, such as Revit or Archicad. These elements contain IFC classes, such as IfcWall, as well as attributes, which are then exported as an IFC file.
• Model View Definition (MVD): To limit data volumes, filtered views are used, for example a Coordination View for coordination or specialised views for quantity take-offs.
• Referencing: IFC files serve as reference models that are not directly edited. Engineers link them into their own software to prevent accidental changes to other disciplines’ models.
• Coordination: In coordination software, such as Solibri, discipline-specific models are combined and automatically checked for clashes.

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IFC vs. DWG/CAD

• DWG/DXF: Drawing and geometry exchange, often without semantic depth.
• IFC: BIM exchange with geometry plus attributes and relationships. It is designed for collaborative, process-driven workflows, is object-oriented and is structured as an IFC schema.

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