How to open SolidWorks files

What SolidWorks files are

SolidWorks saves each part, assembly and drawing in a file of its own:

• SLDPRT is a part: one solid, with the history of features it was built from.
• SLDASM is an assembly: which parts it uses and where each sits. The parts are not inside it: an assembly sent without its SLDPRT files opens empty or with parts missing.
• SLDDRW is a drawing: the 2D sheets with views and dimensions, which also need the part or assembly they show.

All three are Dassault Systèmes’ own format, and no other company’s software reads them fully.

Look at it: eDrawings Viewer

eDrawings Viewer is Dassault Systèmes’ free viewer for SolidWorks files, for Windows and, from the Mac App Store, for the Mac. It opens parts, assemblies and drawings, turns them in 3D and cuts sections, and nothing is uploaded.

It measures only some files: an eDrawings file saved with measuring allowed, or a SolidWorks file last saved by SolidWorks Professional or Premium. A part last saved by SolidWorks Standard opens, without measuring.

Work with it: ask for STEP

If you need the model in another program, or want to 3D print it, ask whoever sent it for a STEP file. STEP is the open format every CAD program exchanges solids in, and SolidWorks saves it under File, Save As. A STEP keeps the exact curved surfaces, the names of the parts and their colors.

A STEP opens in the STEP viewer here, with its parts listed and measured, and turns into an STL for a slicer on STEP to STL, or into a GLB for a web page on STEP to GLB. Nothing is uploaded.

For a print alone, an STL from SolidWorks (File, Save As, STL) is enough. For a drawing, a PDF or a DXF of the sheet is what most people need.

Upload it: online services

Two services open SolidWorks files after you upload them, each with a free account:

• Autodesk Viewer shows SLDPRT and SLDASM files in the browser, and keeps each on Autodesk’s servers for 30 days unless you delete it sooner.
• Onshape, a CAD program in the browser, imports SolidWorks parts and assemblies and exports STEP and STL. Its free plan is for non-commercial use, and every document in it is public.

They are a quick look from any computer. For a design under a nondisclosure agreement, use eDrawings, or ask for a STEP.

JT and Parasolid files

Two other formats of the same world often arrive with SolidWorks parts.

• JT (.jt) is Siemens’ format for sharing 3D models, published as an international standard (ISO 14306). Siemens gives away JT2Go, a viewer for Windows, iPhone, iPad and Android, which also runs in a browser.
• Parasolid (.x_t, .x_b) is the native format of the Parasolid modeling kernel, which SolidWorks, Solid Edge, NX and Onshape are built on. JT2Go opens it too, Autodesk Viewer shows it, and Onshape’s free plan imports it. For a file that opens here, ask for STEP: every program that writes Parasolid writes STEP too.

What opens here

• The STEP viewer opens the STEP that SolidWorks exports, measures it, and saves an STL, OBJ, GLB or 3MF.
• STEP to STL turns a STEP into a mesh for a slicer, at the quality you choose.
• STL to STEP goes the other way, for a mesh you want to open in SolidWorks.

Drop a SolidWorks file on any page and it says what to do with it. Nothing you open on tab3d is uploaded.

What this guide says about other programs was checked on their makers' own websites on October 21, 2026. tab3d is not affiliated with any of them.

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