AutoCAD DWG & DXF Previewer for VS Code

Open, view and inspect AutoCAD .dwg and .dxf drawings in VS Code — no AutoCAD, no license, no upload.
A free, open-source DWG viewer and DXF viewer with layers, search, quantity takeoff, Git diff and an MCP server for AI agents.

• Open DWG files without AutoCAD. A built-in WebAssembly build of GNU LibreDWG reads the drawing. Nothing to install, no account, no trial.
• Your drawings stay on your machine. No "free online DWG viewer" that wants a client's floor plan uploaded to a random server. Works fully offline.
• Fast. A 45,000-entity site plan opens in about two seconds; reopening is instant.
• Made for people who review drawings, not just glance at them: find text, count blocks, measure lengths and areas, compare two revisions.
• Lets AI agents read the drawing. Claude Code, GitHub Copilot and other MCP clients can answer "how many doors are on this plan?" from the drawing's data instead of guessing from a picture.

1. Install AutoCAD DWG & DXF Previewer from the VS Code Marketplace, or run code --install-extension bumkom.dwg-previewer.
2. Open any .dwg or .dxf file.

That is the whole setup.

• Instant preview — double-click a .dwg or .dxf file and it opens as a drawing, not as binary
• Pan and zoom — scroll to zoom toward the cursor, drag to pan, double-click to fit
• Layers — show or hide any layer, with an object count for each; layers switched off in a DXF start hidden
• Model Space and Paper Space — switch between the model and every layout sheet, viewports included
• Export to SVG or PNG — drop the current view into a document, ticket or chat
• Live reload — the view refreshes when the file changes on disk and keeps your sheet, layers and zoom
• Vietnamese TCVN3 fonts (.Vn*) display correctly

Ctrl+F searches text, block attributes (part numbers, door tags — hidden ones too), block names, layers and object types across every sheet. Click any object to inspect its layer, position, rotation, scale and attributes.

Quantities counts every block (Door-900 × 14) and measures linework, area and hatch area per layer, in the units the drawing declares or the one you pick. Shift-click objects to add up their length and area. Copy the table into a spreadsheet or export it as CSV.

Pick a row to select and zoom to those objects — here, all 57 doors of the plan.

DWG: Compare with HEAD (Git), Compare with File… or two selected files: added objects in green, removed in red, changed in yellow over their old shape, with a list of every change to step through with F7. Useful for reviewing CAD files in a pull request.

The extension runs a local Model Context Protocol server, so an AI agent can read the drawing you have open and answer from its real data.

Setup

Which files an agent can read. Drawings in your workspace folders and drawings open in a preview are free. Any other .dwg / .dxf needs your click on a modal Allow prompt first.

Settings

Limits. It works only while VS Code is open — the server lives inside the extension.

Privacy. The extension itself sends nothing anywhere. When your agent calls a tool, the drawing text, numbers and snapshots it asks for go to the AI model you chose for that agent, and only then. Agents normally ask before calling a tool. The server listens on 127.0.0.1 and requires a token. Note: Connect passes that token to claude mcp add on its command line, so other local processes could see it while that command runs.

DWG: AutoCAD R14 through the AC1032 format (AC1014 – AC1032). DXF: ASCII DXF opens directly, with no conversion step. Binary DXF is not supported and says so instead of opening blank. The format is detected from the file header, so a DWG saved as .dxf still opens.

This is a 2D viewer: 3D solids are not drawn. The toolbar names every entity type in a drawing that it cannot draw yet (LEADER, MULTILEADER, TABLE, WIPEOUT and 3D solids are the common ones).

Do I need AutoCAD to open a DWG file? No. The DWG reader is built into the extension.

Can I edit drawings? No — this is a viewer. Files are opened read-only and never modified.

Are my files uploaded anywhere? Never. Everything runs locally inside VS Code, with no internet connection needed.

A drawing does not open or looks incomplete? See Troubleshooting. Very new or damaged files can be opened through an external converter.

The extension works without any configuration. For files that the bundled converter cannot handle (very new DWG versions, corrupted files), you can install an external converter as fallback:

LibreDWG (open source):

# Ubuntu/Debian
sudo apt install libredwg-utils

# Fedora/RHEL
sudo dnf install libredwg-utils

# macOS
brew install libredwg

ODA File Converter (free for non-commercial use): Download from Open Design Alliance.

{
  "dwgPreviewer.converterPath": "/usr/local/bin/dwg2dxf"
}

{
  "dwgPreviewer.converterPath": "C:\\Program Files\\ODA\\ODAFileConverter\\ODAFileConverter.exe"
}

"Failed to convert DWG file"

• The file may use a DWG version the bundled converter does not support
• Install an external converter as fallback (see Configuration above)
• Or set dwgPreviewer.converterPath to the full path of your converter executable

Drawing looks incomplete

• Some entity types may not be supported yet (check the toolbar banner)
• Objects hidden in the file itself — invisible attributes, hidden dynamic-block states — are left out on purpose, as in AutoCAD

Large files are slow to open

• The WASM converter processes the entire file in memory
• Very large drawings (>50MB) may take a few seconds

Something else? Open View → Output, select DWG Previewer, and attach that log (and the drawing, if you can share it) to an issue.

┌─────────┐     ┌──────────────┐     ┌──────────┐     ┌──────────┐
│ .dwg    │────▶│ WASM         │────▶│ DXF      │────▶│ SVG      │
│ (binary)│     │ converter    │     │ parser   │     │ renderer │
└─────────┘     │ (built-in)   │     └──────────┘     └──────────┘
                └──────────────┘

1. DWG → DXF conversion: a bundled WebAssembly converter (LibreDWG) turns the binary DWG into DXF text, in a worker thread, with no external installation
2. DXF parsing: the DXF text is parsed into a drawing model (entities, layers, blocks, viewports)
3. SVG rendering: entities are drawn as SVG in a webview with pan/zoom

Extension Host (Node.js)          │  Webview (Browser)
──────────────────────────────    │  ──────────────────────
extension.ts (activation)         │  main.ts (toolbar, layers, pages)
dwgEditorProvider.ts (lifecycle)  │  renderer.ts (entity → SVG)
dwg/workerClient.ts ──► worker    │  panZoom.ts (scroll/drag/fit)
── worker thread (out/worker.js) ─│
dwg/converter.ts (DWG→DXF)       │
  ├─ WASM (libredwg-web)         │  export.ts (SVG/PNG output)
  └─ CLI fallback (dwg2dxf)      │
dxf/parseDxf.ts (main parser)    │  Communication:
dxf/hatch.ts (HATCH scanner)     │  Host → Webview: postMessage(DXF_DATA)
dxf/viewport.ts (VP scanner)     │  Webview → Host: postMessage(EXPORT)
ai/ (MCP server, tools)          │

The full architecture, the progress log and the design specs live in the dwg-previewer-docs repository.

npm install          # install dependencies
npm run build        # build
npm run watch        # watch mode
npm run typecheck    # type check
npm test             # unit tests
npm run package      # package as .vsix

To debug: open this project in VS Code, press F5 to launch the Extension Development Host, and open any .dwg file in the new window.

If this extension saved you an AutoCAD launch or a license, buy me a coffee ☕.

GPL-3.0-or-later — see LICENSE.

The extension loads and calls the bundled LibreDWG converter (@mlightcad/libredwg-web, GPL-3.0) in-process, so the extension as a whole is distributed under the GPL. Third-party components and their licenses are listed in THIRD_PARTY_NOTICES.md.

Not affiliated with, endorsed by, or sponsored by Autodesk. AutoCAD, DWG and DXF are trademarks of Autodesk, Inc., used here only to describe the file formats this extension reads.