Free online X3D to FCSTD converter

What the X3D format is

X3D is an XML-based 3D scene format standardized by the Web3D Consortium. It stores geometry, transformations, materials, lights, cameras, animation, and scene hierarchy, and is used for browser-based 3D, visualization, simulation, and interchange.

X3D files are created by Web3D authoring tools, CAD and visualization exporters, and some 3D applications. You may encounter either XML-encoded .x3d files or compressed binary .x3db files. An X3D scene can contain several objects and presentation attributes that do not have direct equivalents in a mechanical CAD document.

What the FCSTD format is

FCSTD is FreeCAD's native document format. It can store a FreeCAD document, including bodies, parts, sketches, feature history, constraints, spreadsheet objects, links, and imported geometry.

FCSTD is useful when the destination application is FreeCAD, but saving imported X3D geometry as FCSTD does not normally create editable parametric features. The result is usually a tessellated mesh or a non-parametric shape inside a FreeCAD document.

How to actually convert X3D to FCSTD

Using the online converter

1. Open the X3D-to-FCSTD converter on 101convert.com; the service can be used free without installing software.
2. Upload the source .x3d file and choose FCSTD as the output format.
3. Start the conversion and download the resulting .fcstd file.
4. Open the file in FreeCAD and check the model tree, units, object placement, and visible geometry before using it in a design.

Using FreeCAD with an intermediate mesh

If direct conversion fails or the source contains unsupported X3D nodes, first export the scene as .obj or .stl with an X3D-capable 3D application. Preserve the original units and apply object transforms before exporting.

1. In FreeCAD, create a new document with File → New.
2. Import the intermediate file with File → Import, or open the Mesh workbench and use its import command.
3. For an STL or OBJ mesh that must become solid geometry, select the mesh, choose Part → Create shape from mesh, and set the sewing tolerance only as high as required to close small gaps.
4. If the resulting shape is closed, use Part → Convert to solid. This step is not possible for open or self-intersecting meshes.
5. Save the document with File → Save as and use a filename such as model.fcstd.

Quality and compatibility limitations

• Parametric history is not reconstructed. X3D describes a scene, not a FreeCAD feature tree; sketches, constraints, dimensions, and manufacturing features must be rebuilt manually.
• Materials, textures, lights, cameras, animation, and interaction nodes may be discarded. FCSTD retains FreeCAD geometry and document objects rather than the full X3D presentation scene.
• Mesh conversion quality depends on X3D tessellation. A coarse source mesh produces visibly faceted or inaccurate geometry; a very dense mesh can make FreeCAD slow and create a large FCSTD file.
• Check scale after import. X3D scenes may use meters or application-specific units, while FreeCAD generally interprets CAD dimensions in millimeters unless the document unit scheme is changed.
• Open boundaries, duplicate faces, inverted normals, and self-intersections prevent reliable conversion to a solid. Run mesh checks in FreeCAD before attempting shape or solid conversion.
• Compressed .x3db input may need to be decompressed or exported by an X3D-compatible application before conversion.