Convert EPRT to STEP

Many CAD systems cannot open an .eprt eDrawings file, while suppliers, manufacturers, and inspection tools often require .step or .stp. Conversion is needed when the recipient must exchange, measure, assemble, or manufacture the part outside eDrawings.

What the EPRT format is

EPRT is an eDrawings part file associated with Dassault Systèmes SolidWorks. SolidWorks creates it as a distributable package for viewing a 3D part, taking measurements, applying markups, and restricting access to model information.

An EPRT is normally supplied instead of the original SolidWorks .sldprt file. It may contain display geometry and limited inspection data, but it does not normally contain the original feature history, sketches, parameters, equations, or design tree. The file therefore is not equivalent to an editable native CAD part.

What the STEP format is

STEP is a neutral CAD exchange format standardized as ISO 10303. A typical STEP file stores precise boundary-representation surfaces and solids, allowing software such as SolidWorks, Inventor, Fusion, CATIA, NX, Creo, FreeCAD, machining systems, and inspection applications to exchange geometry.

STEP is suitable for importing a part into another CAD system, checking interference, creating drawings, preparing CAM data, or assembling it with other models. It generally preserves geometry, not the source application's parametric feature history or design intent. Common application protocols include AP203, AP214, and AP242; the available choices depend on the exporting software.

How to convert an EPRT file to STEP

Request the source file or a STEP export

This is the most reliable method. Ask the sender for the original .sldprt file or for a STEP export made from SolidWorks. In SolidWorks, the sender can open the part and use File → Save As, select a STEP format, choose the required application protocol if available, and verify the exported file in the target CAD system.

Exporting from the original part retains accurate analytic faces and design dimensions that may not be present in the EPRT package. It still does not transfer SolidWorks feature history into STEP.

Check eDrawings Professional for STL export

Current eDrawings installations do not generally provide a direct EPRT-to-STEP export. A licensed eDrawings Professional edition may provide File → Save As or File → Export to .stl, depending on the file, release, and license.

1. Open the EPRT in eDrawings Professional.
2. Confirm that the required body is visible and that measurements are plausible.
3. Use the available STL export command and choose a sufficiently fine chord height or angular resolution.
4. Import the STL into a CAD or reverse-engineering application.
5. Convert or rebuild the mesh and export the resulting body as .step or .stp.

Applications such as FreeCAD can import an STL, create a shape from the mesh in the Part workbench, and export that shape as STEP. Commercial mesh-to-CAD or reverse-engineering software can provide more control. This produces a faceted B-rep or rebuilt approximation, not the original SolidWorks model; it is unsuitable when exact cylindrical, conical, planar, or threaded geometry is required unless those features are reconstructed.

Use a translator only after checking EPRT support

Commercial CAD translators and conversion bureaus sometimes support eDrawings files, but support is product- and version-specific. Confirm that the software explicitly lists .eprt as an input format, rather than only listing SolidWorks .sldprt files, and request a test conversion before purchasing or processing a batch. A translator cannot recover feature history or geometry that was never included in the EPRT.

Mainstream online converters commonly accept STEP, IGES, STL, OBJ, or native CAD files, but reliable direct EPRT-to-STEP services are uncommon. Use an online service only when it explicitly accepts .eprt and identifies STEP as the output; changing the extension or uploading an EPRT to a service that accepts only .sldprt will not convert it. Do not upload confidential, export-controlled, or proprietary models without checking the provider's retention and deletion terms.

Quality and compatibility checks

• Open the resulting STEP in the target CAD system and run its import or geometry diagnostic.
• Compare overall length, width, height, known hole diameters, and critical distances with measurements from eDrawings.
• Check for missing bodies, open faces, self-intersections, gaps, and unwanted mesh facets.
• Confirm the unit system. A millimetre-to-inch interpretation can make valid geometry appear 25.4 times too large or too small.
• Expect eDrawings markups, viewing settings, permissions, hidden-state controls, and measurement annotations to be absent from STEP.

If the EPRT contains only tessellated display data, no conversion tool can recreate the exact source surfaces, manufacturing tolerances, or parametric feature tree. For precision manufacturing, obtain the native part or an author-created STEP file instead of relying on an STL-derived reconstruction.