Can I import an existing model from Revit, AutoCAD or SAP2000?
Using CalcSteel
DXF import (from AutoCAD) is supported: you can import a 2D skeleton of your structure and CalcSteel will create the bar network with nodes and members. For Revit, the recommended workflow is to export a simplified DXF or IFC from Revit first. Native IFC import is planned. Direct import from SAP2000, ETABS or Robot is not supported because their file formats are proprietary and complex. For migration from these tools, the fastest path is usually: reconstruct the geometry from a DXF or screenshots. Most small-to-medium steel frames can be re-modeled in CalcSteel in under 30 minutes using templates (warehouse, portal frame, truss) as starting points.
Key takeaways
- DXF (1982) and DWG carry geometry and section names, but no loads, releases, or results — they are drawing formats, not analysis models.
- IFC (first published June 1996, now ISO 16739-1:2024) is the vendor-neutral BIM standard; CIS/2 is the steel-specific STEP-based format endorsed by AISC.
- SAP2000's native files preserve the most engineering data — but only between analysis tools that speak the same dialect.
- No format is fully lossless: geometry transfers reliably, engineering intent (load combinations, end fixity, code checks) rarely does.
- Round-tripping is a head start, not a finished model: the golden rule is to re-verify supports, releases and loads before running any analysis.
Full guide
Import Revit, AutoCAD & SAP2000: What Transfers
Step-by-step with figures and sources — 9 min read
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