Convert SLDASM to STL

3D-print slicers and many mesh tools cannot open a SOLIDWORKS assembly directly, but they accept STL meshes. Exporting an .sldasm file to STL is usually required before printing an assembly or sending its geometry to a mesh-based workflow.

SLDASM and STL formats

SLDASM is the native assembly format of Dassault Systèmes SOLIDWORKS. It stores the assembly structure, component references, mates, configurations, and display information; component geometry normally remains in linked .sldprt part files and referenced subassemblies.

An .sldasm file alone is therefore often insufficient to open or convert an assembly. Keep its referenced files in their original relative folders, or use SOLIDWORKS File → Pack and Go to create a transferable folder or ZIP package.

STL represents surfaces as triangles. It is widely accepted by slicers such as PrusaSlicer, Ultimaker Cura, Bambu Studio, and OrcaSlicer, and by mesh utilities such as Blender and Meshmixer. STL does not preserve assembly mates, feature history, editable solid parameters, component names, material definitions, or reliable unit information.

Binary STL is usually preferred because it is smaller than ASCII STL. STL can contain multiple disconnected shells, but it does not retain the assembly hierarchy that identifies those shells as separate parts.

Exporting with SOLIDWORKS

SOLIDWORKS Desktop is the most reliable option because it reads native assembly references and configurations directly.

1. Open the .sldasm file in SOLIDWORKS and resolve any missing, lightweight, or suppressed components that must be included.
2. Activate the required assembly configuration. Suppress components that must be excluded; do not rely only on visibility settings unless the export options explicitly exclude hidden components.
3. Select File → Save As.
4. Choose STL (*.stl) as the output type, specify the destination, and click Options.
5. Set output units explicitly. Use millimeters for most 3D-print workflows unless the receiving system requires another unit.
6. Choose a resolution. Fine is usually adequate; use custom deviation and angle tolerances only when curved surfaces, holes, or fits visibly need more facets. Smaller tolerances increase triangle count and file size.
7. Select the applicable assembly-output option. Depending on the SOLIDWORKS release, this may allow one STL containing all components or separate STL files for assembly components.
8. Click OK, then Save.

Export separate STL files when parts need different print orientations, materials, support settings, or post-processing. If several components must become one printed object, their solids should be intentionally merged or unioned before export; merely placing touching or overlapping assembly components in one STL does not create a clean fused solid.

Alternatives and online conversion

If SOLIDWORKS is unavailable, ask the sender for a .step or Parasolid .x_t export of the assembly. These neutral CAD formats preserve boundary-representation solid geometry more reliably than STL and can be opened by many CAD systems before meshing.

Autodesk Fusion can import supported SOLIDWORKS and neutral CAD data, although native assembly import depends on file version and linked-component availability. After opening the geometry, use Fusion's mesh export command, commonly File → Export or Save as Mesh depending on the interface version, and select STL.

CAD Exchanger Cloud is a reputable browser-based option for supported CAD formats and can be useful when a desktop CAD license is unavailable. Upload the complete packaged assembly rather than only the .sldasm file, confirm that the service supports the relevant SOLIDWORKS version, and review data-retention and confidentiality terms before uploading proprietary designs.

Mesh and printing checks

Import the STL into the intended slicer and verify its dimensions immediately. STL does not reliably carry units, so an inch-based design can appear 25.4 times too small when software assumes millimeters.

Inspect the mesh for non-manifold edges, reversed normals, zero-thickness features, self-intersections, internal faces, and overlapping components. Assemblies exported as one mesh often contain enclosed parts or intersecting solids that are valid CAD arrangements but unsuitable for a single printed object.

Do not use an unnecessarily fine STL tolerance to compensate for printer limits. Extra triangles increase export, repair, and slicing time without improving details smaller than the printer's nozzle, layer height, or manufacturing tolerance.