IFC (Industry Foundation Classes)
The open file format that lets different BIM tools exchange the same building model.
Quick Answer
Industry Foundation Classes (IFC) is an open, vendor-neutral data schema and file format for describing buildings and infrastructure in BIM. Maintained by buildingSMART International and published as ISO 16739-1, it lets software from different vendors exchange geometry, properties, and relationships without relying on proprietary formats.
The Full Picture
BIM authoring tools store models in their own native formats, which are readable mainly by the software that created them. That is a problem on a project where the architect, structural engineer, MEP engineer, and contractor each use different tools. IFC exists to give them a neutral way to exchange model information, so a wall authored in one program can be opened as a wall, not just as a pile of triangles, in another.
IFC describes more than shape. A model element carries a type, such as a wall, door, or beam, along with properties like fire rating or material, its relationships to other elements, and where it sits in the spatial structure of site, building, and storey. The schema is maintained by buildingSMART International and standardized as ISO 16739-1, with several published versions, so teams should agree which version they will exchange.
IFC files are produced by an export from the authoring tool, and the result depends heavily on how the model was built and how the export was configured. Exchange requirements, often called Model View Definitions, specify which subset of IFC is needed for a given purpose, such as coordination or quantity extraction. A model that exports cleanly for one purpose can still be unusable for another.
In preconstruction, IFC matters when a contractor receives design models and wants to coordinate, check for clashes, or extract quantities without owning the designer's software. It is also a core part of the open BIM approach. The practical limits are real: geometry and property quality vary by project, and many bids are still awarded from PDF drawings rather than models.
Real Examples
Common Misconceptions
People assume: People assume IFC is just another 3D file format like OBJ or STL.
Actually: IFC carries semantic information such as element types, properties, and relationships, not only geometry.
People assume: People assume exporting to IFC is lossless.
Actually: export quality depends on the authoring model and export settings, and some native data and parametric behavior do not survive the exchange.
Frequently Asked Questions
What does IFC stand for?
IFC stands for Industry Foundation Classes. It is an open data schema and file format for exchanging building and infrastructure information between BIM software.
Who maintains the IFC standard?
buildingSMART International maintains IFC, and it is published as the international standard ISO 16739-1.
What is the difference between IFC and Revit files?
A Revit file is a proprietary native format meant to be edited in Revit. IFC is an open exchange format that other software can read, though it generally cannot reproduce all of a native model's editing behavior.
What is a Model View Definition?
A Model View Definition is a defined subset of IFC for a specific exchange purpose, such as coordination or quantity takeoff, so each party knows which data to export and expect.
Why does IFC matter in preconstruction?
It lets a contractor open and coordinate design models without the designer's software, supporting clash checks and quantity extraction when models are available.