Convert FreeCAD (FCStd) to STEP for CAD Interoperability
Turn a FreeCAD .FCStd document into a STEP file of its finished solids with exact surfaces, in millimeters, ready for SolidWorks, Fusion 360, Onshape or a machine shop's quoting tool. The feature tree, colors and object names stay behind.
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Why Convert FCStd to STEP
FCStd is FreeCAD's native project file, and nothing but FreeCAD opens it. SolidWorks, Fusion 360, Inventor, Onshape and CAM software all import STEP, so when a FreeCAD design has to go to a collaborator, a supplier or an instant-quote service, STEP is the format to send.
The converter opens your document in FreeCAD 1.1 on our server and picks the objects that make up the finished model: the Tip of each PartDesign Body, boolean results and visible primitives, skipping datums and consumed inputs. It combines them and writes them with OpenCASCADE's STEP writer. Nothing is tessellated, so planes, cylinders, cones, tori and B-spline surfaces leave as the same exact surfaces FreeCAD holds, and the receiving program can select faces, measure them and add features.
The file uses the AP214 schema (AUTOMOTIVE_DESIGN in its header) with millimeter units, and each solid stays a separate body. It does not carry the parametric history, sketches, constraints, object names, colors or an assembly structure. The receiving program sees one generically named product containing your solids at the positions they had in FreeCAD, not a tree of named parts.
If names and colors matter to your recipient, export from FreeCAD's own File > Export on a computer with FreeCAD, which writes them. Use this converter when FreeCAD is not at hand, when a quick geometry handoff is enough, or when someone sent you an FCStd you need to open in another program.
A document that holds only sketches or 2D geometry is still exported, as STEP wire curves that CAD programs import as 3D curves you can build on. Copies of the same shape stacked at the same spot are written once, which keeps the file small.
How to Convert FCStd to STEP
- In FreeCAD, recompute (Ctrl+R) after your last change, hide anything that is not part of the deliverable, and save. The converter exports the shapes stored in the file.
- If the model is an assembly that links parts from separate .FCStd files, convert each part file on its own, or export the whole assembly to STEP from FreeCAD.
- Drop the .FCStd file here; STEP is preselected.
- Click Convert. Most documents are done in about a second.
- Download the .step file and import it into your CAD program, or attach it to your quote request.
Key Conversion Features
- Exact B-rep surfaces written by OpenCASCADE's STEP AP214 translator, no mesh in between
- Millimeter units, with each solid kept as its own body at its FreeCAD position
- Exports the finished model: Body tips and boolean results, without datums or consumed inputs
- Sketch-only documents exported as STEP wire geometry instead of being rejected
- Repeated copies of one shape at the same spot written once
- Names the missing files when an assembly links to parts that were not uploaded
Video Tutorial
Changing a FCSTD file to STEP has never been easier! Watch this detailed guide on how to do it completely free right in your web browser. 🔗 Visit MiConvert: https://miconvert.com/en/fcstd-to-step?ut
Frequently Asked Questions
Can SolidWorks or Fusion 360 open the result?
Yes. Both import STEP AP214 and show your solids as imported bodies with exact faces you can select, measure and build on. The FreeCAD feature history does not come along, so you get a plain solid, not a parametric part.
Why did my conversion fail with "no geometry"?
It is the most common failure here. The document had nothing exportable: it was empty, its objects saved no shapes, or it held only meshes imported into the Mesh workbench, which cannot become exact STEP geometry. Open it in FreeCAD, recompute, check that the solid shows, and save again. Mesh-only documents should be converted to STL instead.
The error lists linked part files. How do I fix it?
Your assembly references parts saved in other .FCStd files, which one upload cannot include. The converter names them and stops rather than export half an assembly. Convert each part file separately, or open the assembly in FreeCAD and export it to STEP there.
Do colors and object names survive?
No. This export writes geometry under one generic product name. If your recipient needs colors or named parts, use File > Export in FreeCAD itself.
Will I get .step or .stp, and which AP version?
The file is saved as .step; .stp is the same format, so rename it if a portal insists on that extension. The schema is AP214, which current CAD and CAM programs read.
Is a file from FreeCAD 1.0 or 1.1 supported?
Yes. The converter runs FreeCAD 1.1, so 1.x documents open, as do files from older 0.x versions. A corrupted or truncated FCStd is reported as unreadable; save it again from FreeCAD.
Can it go the other way, STEP to FCStd?
No, FCStd is not an output here. FreeCAD opens STEP directly with File > Open or File > Import, so that direction needs no converter.
How long do you keep the files?
Uploads are deleted from our server as soon as the STEP is written, and the STEP is removed automatically about four hours later. All processing happens server-side. Without an account, files up to 50 MB are accepted.