How to open a DWG file in your browser

Someone emails you a DWG and you need to look at it now. You do not need AutoCAD to do that — and you do not need to hand the file to an unknown website either.

The short version

1. Open TrimCAD in your browser.
2. Drag the DWG onto the page, or use Open.
3. It converts the drawing, tells you what it read, and lets you measure, pan, zoom and edit.

What DWG actually is

DWG is Autodesk's native format and it is a container: geometry, layers, blocks, hatches, dimension styles, text styles and layouts. Reading it means understanding all of that, not just the lines. TrimCAD converts the file and reports anything it did not understand, so you know what you are looking at instead of trusting a picture.

Things worth knowing before you rely on a viewer

• Hatches and fills are often what makes a plan readable — a viewer that drops them shows you an empty building.
• Blocks carry most of the drawing (door swings, title blocks, furniture). If blocks are flattened, editing stops making sense.
• Text includes block attributes — the fields in a title block are usually attributes, not plain text, and they are the first thing naive converters lose.
• Coordinates matter: a drawing that is mirrored or scaled wrongly will still look plausible.

If you need to change something

TrimCAD is an editor, not a viewer: you can move and copy objects, offset, trim, add dimensions and text, and export a DXF the other side can open.

TrimCAD is free and open source. It runs entirely in your browser: your drawings are not uploaded anywhere, and it keeps working with no connection at all. Open the app · Source on GitHub