IFC (Industry Foundation Classes) is the open BIM interchange standard, but it exists in multiple incompatible schema versions. A Revit model exported as IFC4 may fail to open correctly in older Tekla or Navisworks installations that expect IFC2x3. An IFC4x3 file from a rail infrastructure project may not be accepted by a contractor's coordination tool that only supports IFC4. Converting the IFC schema version - without losing BIM data - is a routine requirement in multi-stakeholder AEC projects.
Autoconverter converts IFC files between all supported schema versions through its Convert File Version function - a dedicated version-change operation that rewrites the IFC schema header and converts entity definitions to the target version without reprocessing the geometry.
IFC Schema Versions: What Each One Is
| Schema Version | Status | Key Characteristics |
|---|---|---|
| IFC2x3 | Legacy - widely supported | The most universally compatible version; supported by virtually all BIM tools; publishedby buildingSMART in 2006; still the default export in many applications |
| IFC4 | Current standard | Improved geometry representations (IfcAdvancedBrep, IfcFixedReferenceSweptAreaSolid); better property set handling; improved material definitions; required by EU public infrastructure mandates in many countries |
| IFC4x1 | Extension of IFC4 | Added alignment and infrastructure elements for road/rail; basis for civil infrastructure BIM |
| IFC4x2 | Extension of IFC4 | Added geotechnical data, structural analysis, and port/harbor elements |
| IFC4x3 | Latest - infrastructure BIM | Full infrastructure schema covering roads, railways, bridges, ports, and waterways; ISO 16739-1:2024; required for infrastructure projects in some national mandates |
| IFC4x3 RC/TC/ADD variants | Specific release builds | RC1–RC4 (release candidates), TC1 (technical corrigendum), ADD1, ADD2 (addenda); used when a specific tool implements a particular pre-release build of IFC4x3 |
How to Convert IFC Schema Version Using Autoconverter
📥 Download and Install Autoconverter
Download and install Autoconverter on Windows and launch it from the Start menu.
🔄 Open the IFC Version Conversion Tool
Go to File > Convert File Version… - this opens the IFC version conversion dialog directly without loading the full 3D model into the viewport.
📂 Select the Source IFC File
In the file browser, select your source IFC file and specify the output filename and location.
⚙️ Choose the Target IFC Schema Version
In the IFC Save Parameters dialog, select the target schema version from the dropdown. Available options include IFC2x3, IFC4, IFC4x1, IFC4x2, IFC4x3, and the IFC4x3 release variants (RC1–RC4, TC1, ADD1, ADD2).
💾 Save the Converted IFC File
Click OK. Autoconverter writes the IFC output file in the selected schema version.
Using Convert File Version rather than the standard File > Open / Save As workflow is important - it performs a targeted schema conversion optimized for IFC-to-IFC version changes, preserving BIM entity structure and property sets more accurately than a general mesh conversion would.
Command Line IFC Schema Conversion
For automated pipelines, the IFC version conversion is also available from the command line:
Autoconverter.exe -in "model.ifc" -out "model_ifc2x3.ifc" -file_version "IFC2X3"
Autoconverter.exe -in "model.ifc" -out "model_ifc4.ifc" -file_version "IFC4"
Autoconverter.exe -in "model.ifc" -out "model_ifc4x3.ifc" -file_version "IFC4X3"This enables batch conversion of IFC file libraries to a consistent target version for archive management or coordinated model delivery.
Why IFC Schema Compatibility Matters
Different BIM tools implement different IFC schema versions, and some tools accept only specific versions:
- Revit - exports IFC2x3 and IFC4; IFC4x3 support added in recent versions
- ArchiCAD - supports IFC2x3 and IFC4 import/export
- Tekla Structures - primarily IFC2x3; IFC4 support present but less complete
- Navisworks - IFC2x3 is the most reliably imported version; IFC4 works but may show unsupported element warnings
- Solibri - supports IFC2x3 and IFC4; IFC4x3 support depends on version
- Infrastructure tools (OpenRoads, Civil 3D) - IFC4x3 for road and rail alignment export
If you receive an IFC file that a tool cannot open or shows incomplete data for, the most common cause is a schema version mismatch. Converting to IFC2x3 resolves compatibility issues with most legacy tools.
What Changes When Converting Between IFC Schemas
IFC schema conversion is not a simple header rewrite for major version changes - entities, property sets, and geometry representations differ between schemas:
- Downgrading IFC4 to IFC2x3: some IFC4-specific geometry types (
IfcAdvancedBrep, IfcTriangulatedFaceSet) are replaced with IFC2x3-compatible equivalents (IfcFacetedBrep, IfcShellBasedSurfaceModel). IFC4-only property sets may be dropped or approximated. - Upgrading IFC2x3 to IFC4: entity mappings are well-defined in the IFC specification; geometry is preserved; property sets are migrated to IFC4 equivalents where defined
- Converting to IFC4x3: adds infrastructure-specific entity support; best used when the source model contains alignment, terrain, or infrastructure elements that IFC4x3 represents more accurately
For version-only changes within the same major release (IFC4 → IFC4x1 → IFC4x2 → IFC4x3), the conversion primarily updates the schema declaration and migrates any version-specific entity differences.
Frequently Asked Questions
Which IFC version should I use for maximum compatibility?
IFC2x3 is the safest choice for maximum compatibility - it is supported by virtually every BIM tool currently in use. Use IFC4 when you need the geometry improvements (IfcAdvancedBrep, IfcTriangulatedFaceSet) or when the receiving tool specifically requires IFC4. Use IFC4x3 for infrastructure projects (road, rail, bridge) when the receiving tool supports it.
Will converting IFC4 to IFC2x3 lose any data?
Some IFC4-specific entity types and property sets have no direct equivalent in IFC2x3 and will be approximated or dropped during downgrade conversion. The geometry is preserved, but advanced IFC4 material definitions, classification data, and IFC4-only property sets may be partially lost. For critical BIM data handover, verify the output in the receiving tool and check for missing elements.
What is the difference between IFC4x3 ADD1 and IFC4x3 RC4?
These are specific build variants of the IFC4x3 schema. RC (Release Candidate) builds are pre-publication drafts; TC1 is a technical corrigendum (bugfix release); ADD (Addendum) releases add functionality. When a specific tool specifies which IFC4x3 variant it supports (e.g., "IFC4x3 ADD2"), use the matching variant for best compatibility.
Is there a free trial?
Yes. The free evaluation version of Autoconverter supports up to 10 file conversions including IFC schema version conversion. The full licensed version provides unlimited conversions.
Summary
Autoconverter converts IFC files between IFC2x3, IFC4, IFC4x1, IFC4x2, IFC4x3, and IFC4x3 release variants (RC1–RC4, TC1, ADD1, ADD2) using the Convert File Version function. Use IFC2x3 for maximum legacy tool compatibility; IFC4 for improved geometry and EU infrastructure compliance; IFC4x3 for road, rail, and infrastructure projects. The CLI -file_version parameter enables automated batch conversion of IFC file libraries to a consistent target schema.
👉 Ready to convert? Download Autoconverter and try it free for up to 10 conversions.