Building Information Modelling was supposed to bring interoperability to the construction and architecture sector. In practice, the BIM mandate has often entrenched Autodesk’s position: Revit files are widely exchanged, but they are a proprietary format, readable only in Autodesk software. The IFC (Industry Foundation Classes) open standard was designed to solve this — and the open source tools that support it natively are now mature enough to make a genuine difference.

What IFC Actually Means

IFC is a vendor-neutral, open data schema for describing building and infrastructure assets. Maintained by buildingSMART International, it covers geometry, materials, spatial relationships, properties, and lifecycle data. An IFC file should be readable by any conformant application, regardless of the software used to create it.

“IFC is to BIM what PDF is to documents — a format that should be readable by anyone, regardless of which software they prefer.” — buildingSMART UK

The gap between this ambition and reality has historically been significant. IFC support in proprietary tools has been inconsistent, and round-tripping data through IFC has been lossy. But that is changing — partly because of open source tools that treat IFC as a first-class format rather than an export option.

BlenderBIM: The Emerging Open Alternative

BlenderBIM is a plugin for Blender — the powerful open source 3D creation tool — that adds full IFC authoring capability. Unlike most BIM tools that export to IFC after the fact, BlenderBIM stores data natively in IFC format throughout the design process. This means the IFC file is always complete and accurate, not a derivative of a proprietary model.

Early adopters include small architecture practices looking to avoid Revit subscription costs and a growing number of contractors using it for clash detection and construction sequencing. The plugin is under active development and the community is growing rapidly.

FreeCAD and the Civil Engineering Crossover

FreeCAD, a parametric 3D modeller with strong IFC support, is gaining ground in civil and structural engineering contexts. Its BIM workbench handles architectural geometry and IFC import/export. For firms working on infrastructure projects — roads, bridges, drainage — FreeCAD’s non-destructive parametric workflow has advantages over traditional BIM tools.

The Practical Business Case

For a practice currently paying Autodesk AEC Collection subscription fees — which run at approximately £3,000 per user per year — even a partial transition to open source BIM tools represents material savings. More importantly, a workflow built around IFC rather than Revit files is genuinely interoperable: you can exchange data with clients, contractors, and local authority asset management systems regardless of what software they run.

The transition requires investment in training and workflow adaptation. But the direction of travel in UK public sector procurement — with increasing emphasis on open data standards in contracts — means that IFC fluency is becoming a competitive advantage rather than merely a cost-saving measure.