Free online FCSTD to FBX converter

FBX is required by many 3D applications, game engines, and animation pipelines, while FreeCAD saves editable CAD models as FCSTD documents. Converting the file lets you transfer the model to Blender, Autodesk tools, Unity, or other software that does not read FCSTD directly.

What the FCSTD format is

FCSTD is FreeCAD's native document format. It stores parametric bodies, sketches, Part and Part Design features, constraints, dimensions, assemblies, spreadsheets, and the document's modeling history.

FreeCAD creates FCSTD files when you save a CAD project, so the format commonly appears in mechanical design, 3D-printing, engineering, and open-source CAD workflows. An FCSTD file is a document rather than a simple interchange mesh; its editable feature tree cannot be represented directly in FBX.

What the FBX format is

FBX is a 3D interchange format used for models, polygon meshes, materials, cameras, lights, skeletons, and animation. It is supported by applications such as Blender, Autodesk Maya, 3ds Max, MotionBuilder, and many game engines.

FBX is appropriate when the destination application needs a polygonal model for rendering, rigging, animation, visualization, or real-time use. It does not preserve FreeCAD's sketches, constraints, feature history, or parametric editing operations.

How to convert FCSTD to FBX

Using FreeCAD and Blender

1. Open model.FCStd in FreeCAD.
2. Recompute the document with Edit → Refresh or the relevant recompute command, and make sure the final bodies or parts are visible. Hide construction geometry, sketches, and intermediate features that should not be exported.
3. Select the finished Body, Part, or visible solids in the tree. For an assembly, select the components you need and check their placement before export.
4. Choose File → Export, select Wavefront OBJ (*.obj), and save the result as model.obj. If OBJ is unavailable in the installed FreeCAD build, export STL instead; Blender can import both formats.
5. In Blender, choose File → Import → Wavefront (.obj) or File → Import → STL, then open the exported mesh.
6. Check the model's orientation, dimensions, origin, and separate objects. Apply any required transforms with Object → Apply → Scale before exporting.
7. Choose File → Export → FBX (.fbx). Enable Selected Objects if only part of the Blender scene should be included, set the required axis and scale options, and save as model.fbx.

For a conversion without installing desktop software, the built-in converter on 101convert.com can convert the file online for free. Upload the FCSTD file, choose FBX as the output, run the conversion, and download the result; private or commercially sensitive CAD files should be handled according to the service's privacy terms.

Optional FreeCAD mesh export

For repeatable exports, FreeCAD's Python console can write a selected mesh-capable object to OBJ:

import FreeCAD as App, Mesh
doc = App.openDocument("model.FCStd")
Mesh.export([doc.getObject("Body")], "model.obj")

Replace Body with the actual object name shown in the FreeCAD tree. This exports tessellated geometry, not the original parametric model; Blender is still required to write the FBX file.

Quality, compatibility, and limitations

The OBJ or STL intermediate converts exact CAD surfaces into triangles. Increase the tessellation or mesh deviation quality in FreeCAD before export when curved surfaces show visible faceting; reducing the deviation creates more polygons and a larger FBX file.

OBJ may preserve separate objects and basic material assignments, but STL normally contains geometry only. FreeCAD colors, textures, transparency, assembly metadata, constraints, and feature history may therefore be missing or require manual reconstruction in Blender.

Check units after import. CAD files are commonly modeled in millimeters, while FBX pipelines may interpret values using centimeters or another scene unit. Compare a known dimension and adjust Blender's unit settings or export scale before sending the FBX to the target application.