Convert STEP to SLDPRT

A supplier or customer may deliver a neutral .step model, while SOLIDWORKS workflows require .sldprt files for drawings, assemblies, PDM vaulting, or downstream edits. Opening the STEP file in SOLIDWORKS and saving it as a part creates a native SOLIDWORKS document, but not usually the source model's feature history.

STEP format

STEP, normally stored as .stp or .step, is an ISO 10303 neutral CAD exchange format. Mechanical CAD users exchange it between systems such as SOLIDWORKS, CATIA, Siemens NX, Creo, Inventor, Solid Edge, Fusion, Rhino, and FreeCAD.

STEP can carry solid and surface geometry, assembly structure, component names, colors, layers, and, in some variants, product manufacturing information (PMI). AP214 and AP242 are common mechanical-design exchange protocols; AP242 can support more modern model-based-definition data, but retained data depends on both CAD systems and export settings.

SLDPRT format

.sldprt is the native SOLIDWORKS part-document format. It can contain solid and surface bodies, sketches, configurations, custom properties, materials, equations, reference geometry, appearances, and parametric features.

A STEP import normally becomes one or more imported solid or surface bodies in an SLDPRT document. The resulting file supports measurements, sections, drawings, assembly insertion, custom properties, and added SOLIDWORKS features, but imported geometry is usually not an editable reconstruction of the original CAD feature tree.

Convert with SOLIDWORKS

SOLIDWORKS desktop is the preferred converter because it writes its own native format and includes import-repair tools.

1. Select File → Open, then choose the STEP file. Set the file type to the available STEP option, typically STEP AP203/214/242 (*.step; *.stp).
2. Use Options in the Open dialog if shown. For an assembly STEP file, choose an assembly import mode when separate components are needed; import as a part only when a single multibody part is intended.
3. Inspect the FeatureManager design tree after import. Confirm the expected body count under Solid Bodies or Surface Bodies.
4. Run Tools → Evaluate → Import Diagnostics. Use Attempt to Heal All, examine remaining faulty faces or gaps, and save the repaired result from the diagnostics interface.
5. Select File → Save As, choose SOLIDWORKS Part (*.sldprt), and save the file, for example housing.sldprt.

If the STEP source represents an assembly, preserve it as a SOLIDWORKS assembly (.sldasm) with referenced part files rather than saving the top-level model as one SLDPRT. A single multibody SLDPRT is appropriate only when separate assembly components are not required.

Alternative converters

CAD Exchanger provides desktop translation and inspection tools and also offers cloud conversion services. Before using either edition, verify its current format matrix and license explicitly list .sldprt as an output format; support can vary by product edition and SOLIDWORKS release.

Online conversion is suitable only for non-confidential models and basic geometry checks. Cloud services may impose file-size limits, alter assembly handling, or retain uploaded data under their service terms. Do not upload controlled, proprietary, export-restricted, or customer-confidential CAD files without approval and an acceptable data-processing agreement.

Geometry and compatibility checks

STEP transfers geometry and selected metadata, not the original parametric design intent. Source extrudes, fillets, patterns, sketches, mates, equations, and feature names generally arrive as an imported body.

For suitable machined parts, try Insert → FeatureWorks → Recognize Features after import. FeatureWorks can recognize some holes, extrusions, cuts, and patterns, but complex blends, freeform surfaces, threads, and many patterned faces commonly remain imported geometry.

Check critical dimensions, units, hole sizes, body count, mass properties, and assembly component count against the source. Repair or investigate open surfaces, missing faces, unexpected multiple bodies, and unit discrepancies before releasing the SLDPRT.

SLDPRT compatibility is release-dependent: files saved in a newer SOLIDWORKS release may not open in older installations unless an applicable previous-version save option is available. Confirm the recipient's release, test the delivered file in that environment when possible, and include the original STEP file as a neutral fallback.