Bonsai (BlenderBIM) — The Complete Guide: Free Open BIM and IFC Modelling

Bonsai, formerly BlenderBIM, is an open-source add-on for Blender that turns it into a full BIM environment. It is part of the IfcOpenShell project, and its fundamental difference from commercial BIM software is that it works directly on the IFC file — not on a closed format that exports IFC at the end. What you build is the IFC itself.

Bonsai (BlenderBIM)

IfcOpenShell

Native IFC editing inside Blender — open-source BIM.

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Blender

Blender Foundation

Full 3D suite — modelling, visualisation and presentation-quality rendering, with Python scripting.

Architecture Mechanical Engineering Completely Free Open Source Linux macOS Windows 3D & Visualisation

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What you can do in Bonsai

Building modelling — walls, slabs, columns, beams, doors, windows and stairs, by element types and material layers.
Information — property sets, classifications, materials and project structure (site, building, storeys).
Drawings — plans, sections and elevations generated from the model, with dimensions and annotations.
Quantities and costs — quantity take-off from the model, cost schedules and work schedules (4D).
Coordination — opening other consultants' models, clash detection and BCF.

How to start

1. Install Blender from the official site. 2. Install Bonsai as an extension from inside Blender. 3. Create a new IFC project — or open an IFC you received. 4. Set up storeys and wall types before you start drawing. 5. Always save as IFC. If you know Blender this will feel natural; if not, go through Blender's navigation basics first.

What's missing

The learning curve is double — both Blender and IFC concepts. Some tools are still under active development and the interface changes between versions. There are no rich manufacturer libraries as in Revit, and an office whose whole team and consultants work in Revit will find collaboration less smooth. Support is community-based, but very active.

Who it suits

Architects and engineers who want to work in BIM without a licence, openBIM advocates who want full control of the file, students, and anyone who needs to open, check and fix IFC files they received.