— Free tool · no sign-up

DWG viewer. AutoCAD drawings, no AutoCAD.

Drop a .dwg file and see the drawing in your browser, with its layers, zoom, pan and a measuring tool, without installing AutoCAD or uploading the file.

Updated

No DWG file at hand?

01— The format

What a DWG file is, and why it is hard to open

DWG is the native file of AutoCAD and of most of the CAD programs built to replace it; it is a closed, binary format, so only software that has reverse-engineered it can read it.

DWG ("drawing") has been the file AutoCAD saves since 1982. BricsCAD, DraftSight, ZWCAD, progeCAD and many architecture, millwork and sheet-metal programs save it too, which is why it is the file architects, engineers, fabricators and shops trade most. Its first six bytes name the format version: AC1032 is the AutoCAD 2018 format, which AutoCAD releases since then still save; AC1027 is 2013, AC1024 is 2010, AC1015 is 2000.

Autodesk has never published the DWG specification. Programs that read it either license a reader or reverse-engineer the format, as the Open Design Alliance and open-source projects have done. That is why a DWG cannot be opened by double-clicking it on a computer without CAD software, and why most online viewers ask you to upload the file to their server first.

This viewer reads the DWG on your own device instead. acad-ts, an open-source TypeScript port of the ACadSharp library, rebuilds the drawing in a Web Worker and writes it back out as DXF, the open text form of the same data; dxf-viewer then draws it with WebGL. Your file is never sent anywhere.

02— Method

How to open a DWG file

Four steps turn a DWG on your disk into a drawing you can read and check. This is the general method, and what this tool does at each step.

  1. 01Find the version

    Every DWG opens with its release code. A reader that does not know the code cannot open the file, so an older viewer often fails on a drawing saved by a newer AutoCAD.

    This tool: reads DWG files from AutoCAD R14 (AC1014) to the AutoCAD 2018 format (AC1032), and names the version in the summary above the drawing.

  2. 02Rebuild the drawing database

    A DWG is a database of objects: layers, blocks, text and dimension styles, and the entities that reference them. The reader rebuilds that database before anything can be drawn.

    This tool: acad-ts reads the objects in a Web Worker, so the page stays responsive on a large file, and writes them out as DXF text in your browser's memory.

  3. 03Draw model space

    Model space is where the drawing lives at full size; paper-space layouts are the sheets arranged around it for printing. A viewer draws model space first, in the layer colors.

    This tool: draws model space with WebGL, in the drawing's own layer and object colors, then fits the whole drawing to the frame. Layouts are not drawn.

  4. 04Navigate, inspect and measure

    Reading a drawing means zooming into details, hiding the layers in the way and checking a dimension that is not written on it.

    This tool: wheel, buttons, pinch or keyboard to zoom; drag or arrow keys to pan; a layer list with show and hide; a measure tool that snaps to vertices and centers; a PNG of the current view.

03— Coverage

What the viewer draws, and what it leaves out

Most 2D drawings show complete. These are the objects it draws, and the ones it skips, so a missing detail is not a surprise.

  • Geometry: drawn

    Lines, polylines, arcs, circles, ellipses, splines, points, 2D solids and 3D faces, at their true coordinates, in their layer or object colors.

  • Blocks and hatches: drawn

    Block references, nested blocks and their attributes are drawn where they were inserted; hatches are drawn with their pattern lines or as solid fills.

  • Text and dimensions: mostly drawn

    Single-line and multiline text is drawn in one font, DejaVu Sans, whatever font the drawing names. Dimensions are drawn from the geometry the CAD program saved with them, as AutoCAD does; one saved without it is rebuilt only if it is linear or aligned. Leaders are not drawn yet.

  • Line types and weights: simplified

    Every line is drawn thin and continuous, so a dashed hidden line or a center line shows solid, and line weights do not show.

  • Layouts and viewports: left out

    Only model space is drawn. Title blocks and notes that live only on a paper-space layout do not appear.

  • 3D solids, images and xrefs: left out

    ACIS solids, regions and surfaces, raster images and externally referenced drawings are skipped: their geometry is not stored as lines the viewer can draw, or not stored in the file at all.

04— FAQ

Questions about the DWG viewer.

What it does, what it leaves to you, and what it costs.

No. The file is read in a Web Worker on your own device and never leaves your browser. The page downloads only its own code and, when the drawing has text, one font file from this site; your drawing is not part of either request.

DWG from AutoCAD R14 (1997) up to the AutoCAD 2018 format, which later AutoCAD releases still save, so a DWG from a current AutoCAD, BricsCAD or DraftSight opens. A file from R13 or earlier may not open: save it again from your CAD program as a newer DWG or as DXF.

No. Nothing to install and no account. It works in any recent browser with WebGL, on Windows, Mac, Linux, a Chromebook or a phone, which is where the free desktop viewers stop.

Three simplifications cause most of it: every line is drawn thin and continuous (no dashes, no line weights), all text uses one font, and only model space is drawn, not the layouts. Objects the viewer does not draw yet, such as leaders and ACIS solids, are listed in the section above.

Yes. Turn on Measure, click two points and the viewer gives the distance and its X and Y components in the drawing units. Clicks snap to line ends, vertices, arc ends, circle centers and block insertion points within 12 pixels; the cursor position shows as you move. On a drawing with more than 250,000 snap points, snapping is off and clicks measure exactly where you click.

No, it is a viewer: nothing in the drawing changes. Save view as PNG downloads the drawing as the frame shows it, at your screen’s resolution, on the background you chose; a measurement line is not included. For an editable or plotted copy, use your CAD program.

Yes. No sign-up, no email, no watermark on the PNG and no limit on how many drawings you open. The only cap is 100 MB per file, because the drawing is read in your browser’s memory.

acad-ts by node-projects (MIT license), a TypeScript port of ACadSharp, reads the DWG; dxf-viewer by Artyom Lebedev (MPL 2.0), built on three.js, draws it. Text uses the DejaVu Sans font. All are loaded unmodified, and only after you open a drawing.

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