Free online SKP to STP converter

Mechanical CAD, CNC, inspection, and manufacturing systems often require STEP files, while SketchUp saves models as SKP files. Conversion is useful when an architectural or product concept must be opened in engineering CAD or sent to a supplier.

What the SKP format is

SKP is SketchUp’s native project format, used by architects, interior designers, furniture designers, site planners, and 3D-warehouse users. It stores polygonal faces, groups, components, materials, scenes, styles, tags, and model units. SKP is a polygon-based modeling format, not a parametric mechanical-CAD format with feature history, constraints, or native engineering solids.

What the STP format is

STP, also called STEP and commonly identified by .stp or .step, is an ISO 10303 exchange format. SolidWorks, Autodesk Inventor, Fusion, Siemens NX, CATIA, FreeCAD, CAM software, inspection systems, and many other CAD applications can import it. STEP commonly represents exact surfaces and solid boundary-representation geometry, along with units and, depending on the application protocol, assemblies, colors, and product data. It is generally more suitable than SKP for engineering exchange, dimensional inspection, and downstream CAD work, although conversion quality depends on the source geometry.

Convert with CAD Exchanger

CAD Exchanger Desktop is a practical direct workflow when the SKP model needs to become STEP without an intermediate file. CAD Exchanger Cloud provides a browser-based option for non-confidential files and supported account plans.

1. Open CAD Exchanger and choose File → Open, then select the .skp file.
2. Confirm the imported units against the SketchUp model. An inch-to-millimeter mismatch makes dimensions 25.4 times too large or too small.
3. Inspect the imported structure and remove construction geometry, hidden objects, or unnecessary components if the application exposes those controls.
4. Choose File → Save As or Export, select STEP (*.stp, *.step), and choose an available application protocol. AP242 is a suitable choice when the receiving CAD system supports it; AP214 remains widely supported.
5. Open the exported file in the target CAD system and check units, scale, object count, gaps, and whether expected parts are closed solids.

Convert with Rhino for cleanup

Rhino is useful when the model needs manual inspection or repair before export. Its exact import and export options vary by Rhino version and installed format support.

1. Choose File → Open in Rhino and load the SKP file.
2. Set the Rhino document units to match the SketchUp model. Inspect missing faces, reversed normals, duplicate objects, disconnected edges, and excessive polygon detail.
3. Use suitable repair commands such as Join, ShowEdges, and Check. Avoid applying MeshToNurb to a dense mesh indiscriminately: it can turn every polygon into a separate NURBS face and create an extremely large, difficult-to-use STEP file.
4. Choose File → Export Selected or File → Save As, select STEP (*.stp), and use export settings compatible with the receiving CAD system.
5. Reopen the STEP file in Rhino or another CAD application and verify the transferred geometry, scale, and solid status.

Using SketchUp itself

SketchUp does not provide native STEP export. In supported desktop editions, File → Export → 3D Model can create formats such as DWG, DXF, OBJ, STL, or 3DS depending on the version and license, but none of those exports automatically becomes a valid STEP solid. DWG, DXF, OBJ, and STL are intermediate options that require another CAD or conversion application.

Geometry and compatibility limits

The conversion cannot recreate SketchUp design history, parametric constraints, scenes, styles, component behavior, or material behavior as native mechanical-CAD features. SketchUp models are often made from planar polygon faces, so curved surfaces may become faceted STEP geometry. A file can have a .stp extension and still contain open shells, disconnected faces, or tessellated surfaces rather than usable closed solids.

Before exporting, set the correct model units, delete hidden geometry that should not be manufactured, purge unused components and materials, and simplify detailed 3D Warehouse assets. For a machinable part, verify dimensions against the source and run the receiving CAD system’s geometry check. If the source is a dense architectural mesh or lacks closed volumes, remodeling the part in mechanical CAD is usually more reliable than conversion.

Online conversion and confidentiality

CAD Exchanger Cloud is an appropriate browser option when uploading the model is permitted. Online services can impose upload limits, support fewer import settings, and return geometry that requires the same validation as a desktop export. Do not upload confidential designs unless the service has been approved for that data; retain the original SKP until the downloaded STEP file has been opened and checked in the target system.