Convert SLDASM to STEP

A STEP file is needed when an assembly must be opened in another CAD system, sent to a supplier, or stored in a neutral exchange format. The conversion requires the referenced part and subassembly files, because an .SLDASM file normally stores assembly structure and links to geometry rather than containing every component.

What the SLDASM format is

.SLDASM is the native assembly format used by SOLIDWORKS. It stores component instances, positions, mates, configurations, display states, and links to .SLDPRT parts and other .SLDASM subassemblies.

Keep the main assembly and all referenced files together. Missing parts can cause unresolved references, empty components, or an incomplete export. SOLIDWORKS Pack and Go is the safest way to collect the assembly, parts, subassemblies, and referenced files into one transfer folder or archive.

What the STEP format is

STEP is an ISO 10303 neutral CAD format, usually saved with the .step or .stp extension. It is supported by systems including SOLIDWORKS, CATIA, Siemens NX, PTC Creo, Autodesk Inventor, Fusion, FreeCAD, and many manufacturing and inspection applications.

STEP transfers solid and surface geometry and may preserve assembly hierarchy, component names, colors, and locations. Results depend on the exporter, receiving software, and selected application protocol. It does not preserve the SOLIDWORKS feature tree, sketches, design tables, mates as editable constraints, or native parametric relationships.

Use AP242 when the receiving system supports it. AP214 is often the safer choice for older CAD and manufacturing systems; AP203 remains relevant for some legacy workflows but generally carries less presentation and product-structure information.

How to convert with SOLIDWORKS

1. Use File → Pack and Go to create a working copy containing the main .SLDASM, every referenced .SLDPRT, all subassemblies, and any externally referenced components.
2. Open the copied assembly in SOLIDWORKS and resolve missing references. Check the intended configuration, rebuild the assembly, and resolve relevant errors and warnings before exporting.
3. Choose File → Save As, select STEP AP242 (*.step; *.stp) or the protocol required by the recipient, and specify the output filename.
4. Open Options in the Save As dialog. Select the available assembly and geometry settings required by the destination. The exact options and supported AP protocols vary by SOLIDWORKS release.
5. Save the file and inspect it in the recipient's CAD system or an independent STEP viewer. Check component count, hierarchy, positions, units, colors, and critical interfaces.

If the recipient needs one selectable body instead of an assembly, use File → Save As with the appropriate part output option, or create a part from the assembly and export that part as STEP. This removes or changes the original component structure; use the normal assembly export when separate components and hierarchy must remain available.

How to convert without SOLIDWORKS

CAD Exchanger Desktop can import supported SOLIDWORKS assemblies and export STEP. Add the complete referenced file set, verify that every component loads, choose STEP as the output format, select AP242 or AP214 when available, and export. Import support depends on the CAD Exchanger version, the SOLIDWORKS files' features, and the license.

CAD Exchanger Cloud provides a browser-based alternative when its current service accepts the particular SOLIDWORKS version and package. Upload the main .SLDASM together with its referenced parts and subassemblies, choose STEP, and download the result after processing. Do not upload confidential designs until the service's storage, deletion, encryption, and data-use terms have been reviewed.

Quality and compatibility checks

Uploading only the .SLDASM is the most common cause of failure. Suppressed, lightweight, hidden, display-only, or configuration-specific components can also change what is exported. Activate the required configuration and resolve lightweight or unloaded components before conversion when their geometry is needed.

The STEP result is normally a nonparametric translated model. The recipient can generally measure it and create new features, but cannot edit the original SOLIDWORKS feature history or rebuild its mates. Translation can also alter small gaps, invalid faces, tolerances, colors, units, or component names.

Validate critical geometry by comparing bounding dimensions, hole and interface locations, component count, and—where appropriate—mass properties against the source assembly. STEP files may be larger than the native package because they store translated boundary-representation geometry rather than SOLIDWORKS feature definitions.