Export 3D buildings to STEP -- the ISO standard for CAD data exchange. Used in mechanical engineering, construction, and manufacturing. Precise BREP building models.
Key Features

About STEP Format
STEP (ISO 10303) is the international standard for model exchange and the common language of heavy CAD: SolidWorks, CATIA, Inventor, Creo and the free FreeCAD read and write it as standard. Unlike mesh formats, STEP stores real solids with faces and edges, so the model can be cut, merged and measured like an ordinary part.
Buildings from OpenStreetMap in STEP are needed where the city ends up in an engineering assembly: a stand or a model for milling, tooling, fitting equipment into existing development, a three-dimensional site scheme in an environment where everything else already lives in STEP.
What you get: a file with an assembly of solids where each building is extruded into a prism by its height (the height tag, otherwise the number of floors, otherwise 9 meters by default). The roofs are flat — this is volumetric massing, not an architectural model. The origin is the center of the chosen area and the coordinates are metric; after the import check the units in your CAD so that the assembly scale matches what you expect.
The default schema is AP214, the most compatible one; if needed, the file is built to the newer AP242. Roads, water and other flat layers do not get into STEP: the export is volumetric and takes only the buildings.
What Program Opens STEP Files
The following programs and applications can open, edit, and work with STEP (ISO 10303 CAD Exchange) (.step) files exported from OSM2CDR:
Format specifications
- Open standard
- 3D coordinates supported
- Lossless (no quality loss)
- Stores feature attributes
- Output: 1 file
- STEP AP242 (ISO 10303). Mechanical/CAD interchange standard. Opens in SolidWorks, Inventor, FreeCAD, CATIA.
Who Uses STEP Maps
How to Export STEP
How to Open After Export
- FreeCAD (free) — File > Open; the model arrives as solids that can be merged, cut and measured.
- SolidWorks, Inventor, Fusion 360 — STEP import is standard; when inserting into an assembly, check the units and set the scale if needed.
- A check before work — open the file in a free viewer and make sure there are as many solids as you expected and that the assembly landed in the right place.
- If you only need the look and printing — take STL: it is lighter, prints directly and can do pitched roofs.
- A large territory — take a fragment: every building becomes a separate solid, and hundreds of thousands of solids will take any CAD painfully long to open.
Popular maps in STEP
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