IFC2x3 vs IFC4 vs IFC4x3: differences and which to use

When you export from Revit, ArchiCAD, or Tekla, you usually have to pick an IFC version. Most teams default to whatever the previous project used, which is fine — but if you are setting up a new exchange protocol or unsure which version your recipient expects, here is a practical breakdown.

Quick recommendation

• Sharing a building model to a partner with unknown software? Use IFC2x3. Maximum compatibility — every IFC-capable tool reads it.
• Modern building project, all parties on recent software (≤ 4 years old)? Use IFC4 (Reference View). Better materials, better property support.
• Infrastructure work — rail, road, bridge, ports, tunnels? Use IFC4x3. It is the only version that defines those entity types.

IFC2x3 (released 2006)

IFC2x3 has been the de-facto standard for nearly two decades. It is the version that virtually every IFC-aware tool implements robustly. Property sets, spatial structure, and building element types are all well-defined.

Pros: universal compatibility, mature implementations, well-known property sets like Pset_WallCommon.
Cons: dated geometry representations, no material library improvements, no infrastructure entity types.

IFC4 (released 2013, updated as IFC4 ADD2 TC1)

IFC4 modernised the schema: better material assignments, expanded property templates, tessellated geometry (triangle meshes alongside the parametric BReps), and improvements to the relationships graph. It is divided into Model View Definitions (MVDs) — the most relevant in practice are:

• Reference View — geometry as tessellated meshes; smaller files, easier consumption.
• Design Transfer View — full parametric geometry; higher fidelity but larger and harder for downstream tools to consume.

Pros: better material model, smaller files (Reference View), more expressive property templates.
Cons: some older tools have weaker IFC4 import — verify with the recipient.

IFC4x3 (released 2024, ratified as ISO 16739:2024)

IFC4x3 is the most significant extension since IFC4. It adds entity types for infrastructure assets — rail, road, bridge, ports, tunnels, and water — that simply did not exist in IFC4. If you are working on civil/infrastructure BIM, IFC4x3 is the version to use.

For pure building work (housing, offices, hospitals), IFC4x3 is mostly a backwards- compatible superset of IFC4 — there is no harm in exporting it, but no big advantage either.

Pros: full infrastructure coverage, alignment geometry, modern schema.
Cons: not yet universally supported by older or niche tools.

How to tell which version a file uses

Open the IFC file in any text editor — the second line typically reads:

• FILE_SCHEMA(('IFC2X3'));
• FILE_SCHEMA(('IFC4'));
• FILE_SCHEMA(('IFC4X3')); or ('IFC4X3_ADD2');

Or just open it in IFC Navigator — the viewer auto-detects the schema and parses all three versions.

What about IFC5?

IFC5 is in development at buildingSMART and is a much larger restructuring of the schema (moving toward a USD-style stage representation). It is not yet a finalised release as of mid-2026 — keep using IFC4 or IFC4x3 for now.