What is an IFC file? A practical guide

IFC stands for Industry Foundation Classes. It is an open, vendor-neutral file format for sharing Building Information Modelling (BIM) data between software tools. If you have ever received a .ifc file from a colleague using a different design tool, IFC is what made that exchange possible.

Why IFC exists

Architects, structural engineers, MEP engineers, contractors, and facility managers all use different software. Architects favour Autodesk Revit or Graphisoft ArchiCAD; structural engineers use Tekla Structures, Allplan, or SCIA; contractors use Navisworks, BIM 360, or Solibri. Each tool has its own native format (.rvt, .pln, .tek, etc.) that other tools cannot read directly.

IFC fills that gap. Every major BIM tool can export to and import from IFC. It is the lingua franca of BIM, and it is an open ISO standard (ISO 16739) maintained by buildingSMART International.

What is in an IFC file

An IFC file describes a building (or any built asset) as a structured graph of typed objects. Among other things it contains:

• Geometry — walls, slabs, columns, beams, doors, windows, pipes, ducts, fittings — represented as parametric profiles, swept solids, BReps, or triangulated meshes.
• Spatial structure — site → building → storey → space hierarchy that groups elements logically.
• Properties — every element carries direct attributes (Name, GlobalId, Tag, etc.) plus arbitrarily many property sets (Pset_*) attached by the authoring tool.
• Relationships — connections between elements (a door is hosted by a wall; a pipe segment connects to a fitting), classifications, materials, and quantity breakdowns.
• Project metadata — units, coordinate system, project name, authoring application, and timestamps.

What an IFC file is not

IFC is not a native editing format. You can open, view and inspect an IFC file in any IFC-aware tool, but round-tripping edits back to the original Revit or ArchiCAD model is not lossless. Always treat IFC as an exchange and reference format, not the master copy of your design.

IFC versions

The most common versions in the wild today are IFC2x3 (released 2006), IFC4 (2013), and IFC4x3 (2024). IFC4x3 is the current generation and adds infrastructure asset types (rail, road, bridge, ports, water). Most building-only projects still ship in IFC2x3 or IFC4.

See IFC2x3 vs IFC4 vs IFC4x3 for a side-by-side comparison.

How to open an IFC file

You do not need Revit, ArchiCAD, or any installed BIM software to open an IFC file. You can open it directly in your browser with IFC Navigator — drag the file in, the model renders in seconds, and clicking any element shows its IFC properties.

Other free options include desktop tools like BIMvision and Solibri Anywhere. See how to view IFC files online for free for the trade-offs.