What is the EPRT file format?
An .eprt file is a published eDrawings Part document produced by SOLIDWORKS (Dassault Systèmes), representing the view-only counterpart to a native .sldprt CAD part file. It belongs to the eDrawings family alongside .easm (eDrawings assemblies) and .edrw (eDrawings 2D drawings), which collectively allow CAD geometry to be shared with recipients who do not hold a SOLIDWORKS licence.
The file stores tessellated or precise B-rep geometry for a single mechanical part, together with named views, annotations, and optional markup data. When the publishing engineer enables measurement access, the recipient can take dimensions directly on the 3D model in eDrawings Viewer. If SOLIDWORKS Simulation results are embedded during export, the viewer can also display FEA outputs such as von Mises stress maps, displacement fields, and factor-of-safety plots.
.eprt files are opened with the free eDrawings Viewer, available for Windows, macOS, iOS, and Android. The format is a downstream publication only - it cannot be used to reconstruct the original parametric SOLIDWORKS model, making it functionally comparable to a PDF for a single 3D part. The originating engineer controls what geometry is embedded: a lightweight tessellated model gives a visual-only result, while precise geometry inclusion enables accurate measurement and cross-section analysis. File sizes range from roughly 50 KB for simple parts to 50 MB for complex geometry with embedded simulation data.
Security & safety
RISK: LOWEPRT files are passive CAD viewing data and pose no malware risk when opened in eDrawings Viewer. The practical concern is confidentiality: a part file may reveal proprietary product geometry. Only download eDrawings Viewer from the official SOLIDWORKS/Dassault site.
Format details
in a nutshellPrograms that open EPRT files
Windows2 apps
SolidWorks
Paid Open and view EPRT files; for editing the part itself, the original SLDPRT is needed. 
eDrawings Viewer
Free Download the free eDrawings Viewer, double-click the .eprt to rotate, zoom, measure and inspect the part. No SOLIDWORKS license needed. 
macOS1 app
eDrawings Viewer for Mac
Free Download the macOS build of eDrawings Viewer and open the .eprt to view and measure the part. 
Android1 app
eDrawings (Android app)
Free Open the .eprt in the eDrawings Android app to view and rotate the part.
eDrawings (iOS app)
Free Open the .eprt from Files/email in the eDrawings app to view the 3D part on iPhone/iPad. Technical details
deep spec| Format family | One of three eDrawings file types: `.eprt` (part), `.easm` (assembly), `.edrw` (2D drawing) |
| Container | Proprietary compressed eDrawings container; not a standard ZIP or OLE2 structure |
| Source format | Published from `.sldprt` (SOLIDWORKS Part) - downstream view-only output; original parametric model is not recoverable |
| Geometry representation | Tessellated mesh or precise B-rep geometry; publisher controls which is embedded at export time |
| Optional FEA data | May embed SOLIDWORKS Simulation results: von Mises stress, displacement, deformation, and factor-of-safety plots |
| Measurement capability | Dimensional measurement enabled only when publisher includes precise geometry; disabled for tessellated-only exports |
| Platform support | Windows, macOS, iOS, Android via eDrawings Viewer (free download) |
| Typical size | 50 KB - 50 MB depending on part complexity and whether simulation data is embedded |
| Version compatibility | Newer eDrawings Viewer versions open older `.eprt` files; older viewers cannot open files from newer eDrawings versions |
| Compression | Proprietary compression; file is significantly smaller than the source `.sldprt` |
| Editability | Non-editable; format is a publication target, not a CAD interchange format |
| MIME type | `application/octet-stream` (no registered MIME type) |
| Released | 2000 (eDrawings, SolidWorks Corporation) |
| Specification | www.edrawingsviewer.com |
EPRT conversions
Community Q&A
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