Convert SLDASM to OBJ

A game engine, browser viewer, renderer, or mesh editor may require OBJ because it cannot open a SolidWorks assembly. The conversion creates a geometry-only mesh that is easier to share, visualize, and archive than a native CAD assembly.

What the SLDASM format is

.sldasm is SolidWorks' native assembly format. It stores component placement, mates, configurations, display states, and references to separate .sldprt part files and nested .sldasm subassemblies.

An SLDASM file is normally not self-contained. Keep every referenced part and subassembly available, including files in external references. In SolidWorks, use File → Pack and Go to collect the assembly and its dependencies in a folder or ZIP archive; preserve the original filenames and relative paths.

What the OBJ format is

.obj is a text-based polygon-mesh format supported by Blender, Maya, 3ds Max, many game-engine workflows, rendering applications, mesh editors, and 3D viewers. It stores vertices, faces, normals, texture coordinates, and object or group information. Material assignments are commonly stored in a separate .mtl file, with image textures alongside it.

OBJ is useful for visualization, rendering, animation, and mesh editing, but it is not a parametric CAD format. Conversion tessellates SolidWorks surfaces into polygons and discards sketches, dimensions, feature history, mates, configurations, tolerances, and editable solid parameters.

How to convert an SLDASM file to OBJ

Direct export with CAD Exchanger Desktop

1. Create a Pack and Go copy of the assembly, or place the top-level .sldasm, all referenced .sldprt files, and nested assemblies in an accessible folder.
2. Install a CAD Exchanger Desktop edition whose current format list includes SolidWorks assembly input and OBJ output. Open the top-level file with File → Open; resolve any missing-reference prompt before exporting.
3. Inspect the assembly tree and hide components or construction geometry that should not be included. Retain separate components if the destination application must select them individually.
4. Set the tessellation, chordal-deviation, angle, or mesh-quality options. Use finer settings for fillets, cylinders, small holes, and curved surfaces; use coarser settings for previews or very large assemblies.
5. Use File → Export, select OBJ, enable material or texture export when available, and save the output. Keep the generated .mtl and texture files beside the OBJ.
6. Open the result in Blender or the target application and check scale, orientation, missing components, normals, object separation, and materials.

CAD Exchanger is a practical direct-conversion option because it can read SolidWorks assemblies without SolidWorks installed. Input and output formats can vary by product edition and version, so confirm the current support matrix before purchase or batch conversion.

SolidWorks, STL, and OBJ

SolidWorks does not generally provide native OBJ export. If SolidWorks is available but a direct OBJ exporter is not, export the assembly as STL and then convert that mesh to OBJ.

1. Open the assembly in SolidWorks and choose File → Save As.
2. Select STL (*.stl), open Options, choose the required units and resolution, and use binary STL for a smaller intermediate file. Set deviation and angle values finely enough to preserve curved surfaces. Use the assembly option for one file or separate component files as required by the SolidWorks version.
3. In Blender, choose File → Import → STL and load the STL.
4. Choose File → Export → Wavefront (.obj). Export selected objects only when necessary, and enable normals, UVs, and material options when the destination requires them.

This method performs tessellation in SolidWorks and then converts the resulting mesh, so it can lose component separation, colors, or assembly organization. Separate STL files preserve more component-level control than one combined STL.

Online conversion

CAD Exchanger Web is an option for non-confidential files when its current format matrix lists .sldasm input and OBJ output. Upload the complete dependency set, not only the top-level assembly: use the service's multi-file upload or a Pack and Go ZIP if archives are supported, then select OBJ and download every output file.

Check upload limits, supported SolidWorks versions, retention policies, and the treatment of external references before submitting a file. Do not use a public online converter for confidential or export-controlled designs. Missing dependencies, unsupported features, large assemblies, and server-side size limits can produce incomplete output or a failed conversion.

Quality and compatibility limits

• Missing references can remove parts or prevent conversion. Include all referenced parts, subassemblies, and external files.
• Fine tessellation improves curved surfaces but increases polygon count, memory use, and export time. Coarse settings produce faceting on cylinders, fillets, and small holes.
• OBJ has no universally enforced unit declaration. Record the SolidWorks document units and set the import scale explicitly; millimetre models may require adjustment in non-CAD software.
• OBJ material handling varies by exporter and importer. Keep the .mtl file and texture images with the OBJ, and preserve their filenames and relative paths.
• An exporter may write one combined mesh or multiple objects and groups. Verify the result if downstream users need to hide, select, or edit individual components.
• Check face normals after import. Reversed normals can make surfaces invisible or incorrectly shaded, especially after additional mesh processing.
• The OBJ contains approximate tessellated geometry, not manufacturing data. Retain the original SLDASM and dependent SLDPRT files as the authoritative CAD source.