Free CAD viewer for Windows 10 and 11
PartLens for Windows is a free, offline CAD viewer for Windows 10 and 11. It opens STEP, IGES, CATIA V5, 3DXML, STL, OBJ, PLY, glTF and DXF files, with a searchable parts tree, measurement, exact sections, drafting and revision compare. No account and no upload.
Most free CAD viewers for Windows either open one vendor's files, need an account, or send your parts to a cloud service. PartLens runs entirely on the PC, with an exact geometry kernel built in for sections and measurements on STEP files.
Files it opens
| Format | Measurement |
|---|---|
| STEP / STP | Exact geometry, labelled per result |
| IGES / IGS | Surfaces and curves |
| CATIA V5 CATPart / CATProduct | Fitted bores and planes, marked ≈ |
| 3DXML | Approximate ≈ |
| STL, OBJ, PLY, glTF / GLB | Approximate ≈ (meshes) |
| DXF | True centres and ends |
What it does
- Parts tree you can search, with isolate, hide and show for each placed instance.
- Measurement with magnetic snapping, and a label on every number saying exact or approximate.
- Exact sections and orthographic drafting with dimensions, exported as DXF, SVG or PDF.
- Revision and left/right-hand compare in two synchronised views.
- Reports with notes and captures, exported to PDF, Excel, CSV or HTML.
Install and open a file
- Get PartLens free from Google Play or as a Windows download.
- On Windows: Install the free Windows app, then double-click the file, drag it onto the window, or use Open CAD….
- On Android: Tap the file in WhatsApp, Gmail, Drive or your file manager and choose PartLens under Open with, or open PartLens and tap Open.
Nothing is uploaded: the file is read on your device, with no account.
About the download
The Windows app is a free download from this site. It is an unsigned preview, so Windows may show a publisher warning the first time: choose More info → Run anyway. Your projects are kept when you install a newer version. The same files also open on Android.
Frequently asked questions
Is there a free CAD viewer for Windows that works offline?
Yes. PartLens for Windows is free and works fully offline, with no account. It opens STEP, IGES, CATIA V5, 3DXML, STL, OBJ, PLY, glTF and DXF files.
Can I open CATIA files on Windows without CATIA?
Yes. PartLens opens CATIA V5 .CATPart parts and .CATProduct assemblies, reading part files from beside the assembly.
Can I measure and section STEP files on Windows for free?
Yes. PartLens measures with exact/approximate labels and cuts exact sections using its built-in geometry kernel.
Why does Windows warn about the PartLens installer?
The Windows build is an unsigned preview, so SmartScreen does not yet recognise the publisher. Choose More info, then Run anyway.
Open your file now, free
Free and offline on Android and Windows. No account, no upload.
Get it on Google Play Download for Windows