truedxf is a TypeScript DXF library that tries to be fast and to draw drawings exactly the way AutoCAD plots them. Try the viewer at https://truedxf.cc: files are opened in your browser and never uploaded.
- AutoCAD is the reference. Over 3 500 generated test drawings are plotted by AutoCAD 2027 and compared with truedxf's output pixel by pixel. When AutoCAD and the DXF reference disagree, AutoCAD wins, and what we learn is written down in research/notes.
- Lossless. The parser keeps every group code, including ones it does not understand. Typed entities, tables and objects are views over the raw tags, so nothing is lost on the way.
- Browser and Node. Everything below the renderer has no DOM or Node dependencies. The viewer parses and builds display lists in a worker and draws them with three.js (WebGL).
- Read every DXF in the wild: R10 to R2018+, ASCII and binary, any code page, and broken files from third-party programs, without crashing and with diagnostics for what was wrong.
- Lose nothing: unknown entities, unknown group codes inside known entities, XDATA, extension dictionaries and 102 groups all survive. Effective properties (ByLayer, ByBlock, layer 0, viewport overrides) can be resolved without the renderer.
- Draw what AutoCAD plots: for a DXF and a plot setup, the same geometry (tessellation, dashes, hatch lines, glyphs), colours, lineweights, draw order and clipping as AutoCAD's plot. The same input always gives the same output.
- A fast, embeddable web viewer for large drawings.
Not goals: writing or editing DXF, reading DWG, 3D shaded or hidden-line views, and CAD editing tools in the viewer.
- AutoCAD output is the truth. Everything else is a hypothesis. Every rendering rule is pinned by a test drawing plotted by AutoCAD. The official DXF reference is wrong in many places (rotation units, PSLTSCALE, leader hooks, …), so it is a starting point, not the answer.
- Lossless first, typed second. Tags are never thrown away. Typed objects interpret them on access.
- Render stored data before regenerating it. A DXF usually carries the answer: dimension and table geometry in their anonymous blocks (drawn as stored, even when stale), final hatch lines, embedded linetypes, proxy graphics. truedxf regenerates only what is missing.
- Deterministic. Float64 on the CPU, no randomness, count limits instead of time limits, fonts only from the sources you give it.
- One geometry pipeline. The frontend does all the work (dashing, hatching, text, lineweight stroking, clipping) and emits a renderer-agnostic display list. The three.js renderer only uploads and draws it. Other outputs (SVG, PDF) can be added without touching the frontend.
- Isomorphic below the renderer. Parsing, the model and display-list building run in Node, browsers and web workers.
- Clean licences. MIT, with MIT/ISC/BSD/Apache-2.0/BSL-1.0 dependencies only. No Autodesk fonts, patterns, linetypes or plot styles are included, and GPL code was read for facts only.
30 feature suites, 3 583 generated cases with AutoCAD references (2026-10-01). Good = F1 score of at least 0.99 when ink pixels within 1 px of same-coloured ink count as matching. Exact = every pixel identical. Measured with the CPU scorer, which draws the same pixels as the browser renderer in plot mode.
3 279 good (92 %), 924 exact (26 %).
| Suite | Cases | Good | Exact | Suite | Cases | Good | Exact | |
|---|---|---|---|---|---|---|---|---|
| calibration | 38 | 38 | 5 | linetypes | 230 | 216 | 65 | |
| lines-curves | 119 | 118 | 78 | hatches | 279 | 247 | 140 | |
| ocs | 91 | 80 | 34 | text | 294 | 278 | 15 | |
| polylines | 99 | 98 | 51 | text-lato | 23 | 21 | 0 | |
| points | 155 | 153 | 115 | mtext | 250 | 209 | 1 | |
| ellipses | 51 | 51 | 22 | attribs | 65 | 64 | 3 | |
| splines | 59 | 56 | 0 | acad-default-fonts | 113 | 91 | 55 | |
| solids | 43 | 43 | 38 | dimensions | 366 | 362 | 1 | |
| colors | 44 | 44 | 10 | leaders | 128 | 111 | 26 | |
| lineweights | 64 | 64 | 7 | layouts | 169 | 155 | 7 | |
| blocks | 88 | 82 | 42 | xclip | 44 | 36 | 0 | |
| transparency | 23 | 21 | 2 | images | 174 | 156 | 137 | |
| draworder | 34 | 34 | 26 | mline | 54 | 40 | 16 | |
| misc | 45 | 40 | 20 | extents | 18 | 9 | 0 | |
| mixed | 37 | 32 | 0 | fileformat | 386 | 330 | 8 |
Most of the remaining gap is TrueType text rasterization (few text cases are pixel-exact). The open work is listed in docs/TODO.md.
| Package | What |
|---|---|
@truedxf/core |
Tokenizer for ASCII and binary DXF, encodings, lossless tag store |
@truedxf/model |
Typed document: header, tables, blocks, entities, objects, property resolution |
@truedxf/geometry |
OCS, arcs, ellipses, NURBS, flattening, stroking, dashing, hatching, clipping |
@truedxf/fonts |
SHX fonts (shape, unifont, bigfont), TrueType, AutoCAD's font resolution |
@truedxf/text |
TEXT and MTEXT parsing and layout |
@truedxf/render |
Layouts, viewports, blocks and properties to a renderer-agnostic display list, with AutoCAD raster rules |
@truedxf/pdf |
PDF underlay content, rendered by PDF.js |
@truedxf/three |
three.js renderer for the display list |
@truedxf/viewer |
Embeddable viewer: worker pipeline, pan / zoom, layouts, layers, picking, measuring |
@truedxf/testkit |
Scoring against AutoCAD: CPU rasterizer, headless Chromium harness, metrics (not published) |
apps/playground is the viewer app behind the website. tools/gen
generates the test drawings (Python, ezdxf), tools/acad plots them with AutoCAD,
tools/corpus runs the parser over a corpus of real-world files.
pnpm add @truedxf/viewer threeimport { DxfViewer } from "@truedxf/viewer";
const viewer = new DxfViewer(document.getElementById("view")!, { background: "dark" });
await viewer.load(file); // File, Blob, ArrayBuffer, Uint8Array or URL
viewer.on("select", async ({ handle }) => console.log(await viewer.inspect(handle)));Without a viewer, loadDxf from @truedxf/model gives you the document and
renderPlot from @truedxf/render a display list or plot. See the package READMEs.
Needs Node 22.18+ and pnpm.
pnpm install
pnpm typecheck && pnpm lint && pnpm test
pnpm playground # the viewer app on http://localhost:5173The test drawings, AutoCAD references and the real-world corpus live in samples/, which is not
in the repository: real-world files are not ours to redistribute, and the references need a local
AutoCAD install. tools/gen regenerates the drawings. Tests that need samples skip without them.
Contributor conventions are in AGENTS.md.
Found a drawing that looks wrong? Open an issue with screenshots and, if you may share it, the file.
MIT. truedxf ships no Autodesk files. The viewer site bundles the Liberation and Noto Sans SC fonts (SIL OFL 1.1). AutoCAD and DXF are trademarks of Autodesk, Inc. truedxf is not affiliated with or endorsed by Autodesk.