A client recently asked us to help open a .DRW file from a supplier. SolidWorks couldn't read it. Neither could eDrawings, DraftSight, AutoCAD, or any of the half-dozen "legacy CAD viewers" you'll find on a quick Google. The supplier insisted it was a standard 2D drawing.

It turns out .DRW isn't a SolidWorks format at all — SolidWorks dropped that extension back in 1998. The file in question came from Pro/DESKTOP, an old PTC parametric modeller that was widely used by European manufacturers and UK design-and-technology schools in the late 1990s and early 2000s. PTC discontinued it around 2008 and the binary format has been undocumented since.

So we built a tool to read it.

The DRW Inspector below decodes what we can pull out of a Pro/DESKTOP .DRW file: the file header, the title block, the full bill of materials, drawing extents, and circular features (holes and round geometry) with their exact coordinates and diameters. It can't render the full drawing — that would require reverse-engineering decades of undocumented geometry encoding — but it gives you enough to confirm what you've been sent, identify the part, and have an informed conversation with the supplier.

The whole thing runs in your browser. No upload, no installation, no account. Your file never leaves your computer, which makes it safe to use on commercially sensitive drawings.

If you've got a Pro/DESKTOP file gathering dust, drag it onto the drop zone below.