Free online SCAD to STP converter

What the SCAD format is

.scad is the source format used by OpenSCAD, a script-based CAD application. A SCAD file contains text commands defining primitives, transformations, Boolean operations, variables, loops, and user-defined modules; it does not directly store a conventional boundary-representation solid in the way a STEP file does.

OpenSCAD creates SCAD files, and repositories of parametric or printable models commonly distribute them. A model may also depend on files referenced with include or use; those dependencies must remain available during import or rendering.

What the STP format is

.stp and .step are filename extensions for ISO 10303 STEP, a neutral CAD exchange format. STEP stores geometric entities such as analytic surfaces, trimmed faces, shells, and solids, allowing different mechanical-CAD systems to exchange a model more reliably than mesh formats such as STL.

STP is appropriate when the recipient needs to measure, position, modify, or manufacture the model in a parametric or solid-modeling application. STEP does not normally preserve OpenSCAD source code, variables, modules, comments, or editable feature history.

How to convert SCAD to STP

The most reliable desktop workflow is to open the SCAD source through FreeCAD's OpenSCAD importer and export the resulting solid as STEP.

1. Install OpenSCAD and FreeCAD. FreeCAD's OpenSCAD workbench uses OpenSCAD to process SCAD syntax, so OpenSCAD must be installed and its executable must be detectable by FreeCAD.
2. Keep the SCAD file together with every referenced library or dependency. Test the file in OpenSCAD first; resolve undefined modules, missing files, and preview-only geometry before importing.
3. In FreeCAD, switch to the OpenSCAD workbench and choose File → Open. Select the .scad file and wait for the imported objects to appear in the model tree.
4. Inspect the result in the 3D view. Hide construction objects and select the final solid or compound that should be transferred.
5. Switch to the Part workbench and choose File → Export. Enter a filename ending in .stp or .step, then confirm the export.
6. Reopen the exported STEP file in FreeCAD or the target CAD program. Check the unit system, solid count, bounding dimensions, holes, and curved surfaces before using it for manufacturing.

For a no-installation option, the free converter on 101convert.com can process the file online. Files containing proprietary designs should be uploaded only when the site's handling and retention terms are acceptable.

Quality and compatibility limitations

Import is evaluated geometry, not source translation: OpenSCAD expressions are executed, and the resulting shape is exported. Parameter controls and the ability to regenerate the model from its original script remain in the SCAD file, not in the STP output.

Use a valid, closed solid whenever possible. Non-manifold edges, self-intersections, zero-thickness faces, unsupported modules, and disconnected fragments can produce missing faces or a STEP file containing surfaces instead of a solid. FreeCAD's geometry checks can help identify invalid imported shapes before export.

OpenSCAD models deliberately approximated with $fn, polygon(), or manually generated meshes may remain faceted in STEP. Increasing $fn improves visual smoothness but increases geometry size and processing time; it does not recreate a mathematically exact cylinder or sphere after the shape has been polygonized.

STEP export generally preserves solid geometry and units, but it does not preserve OpenSCAD colors, comments, rendering settings, or animation logic. AP214 or AP242 export options, when offered by the CAD application, can retain more product and color metadata than a basic AP203 export.