Braižyklė — 2.5D CAD in a browser tab

Draw an outline, give it a thickness, export DXF to the router. No install, no licence, no sign-up. One HTML file.

🇱🇹 Lietuviškas aprašymas: README.lt.md · The app's UI has an LT/EN toggle.

Why this exists

I needed to draw one-off parts for CNC routing — a panel with a few holes, a curved front, a jig. The commercial CAD we had was overkill for that, and the capable free options are licensed for non-commercial use only, which a working shop can't use.

So this does exactly the slice I needed: precise 2D geometry in, a DXF the CAM software accepts out.

What it does

Drawing — line (chained), rectangle, circle, arc (centre → start → end), dimensions. While drawing you can type the numbers: start typing a length, Tab for the angle, Enter to place. Shift constrains to perpendicular / 45°.

Snapping — endpoints, midpoints, centres, quadrants, intersections, point-on-line and grid. The status bar names whatever it just snapped to, so you're never guessing.

Editing — fillet, chamfer, trim against real computed intersections, offset with sharp corners, move, copy, mirror, rotate, rectangular and polar arrays. Every line and circle is also editable numerically in the properties panel (X1, Y1, length, angle, R, Ø).

Parts — closed loops are detected automatically and inner loops become holes. The app reports area, perimeter, cut length and volume — and flags open ends in red, because an unclosed contour is the thing CAM will reject after you've already walked to the machine.

3D preview — the contour is extruded to its thickness (per part), orbit with the mouse. 2D / 3D / split view.

Export — DXF R12 (LINE, ARC, CIRCLE + layer table, mm), SVG, PNG, project as JSON. Construction lines and dimensions are deliberately excluded from the DXF so the CAM software can't mistake them for geometry.

The parts that were actually hard

• Exact arc areas. Shoelace over polyline approximations drifts, and the area feeds the material cost. Arc segments contribute their exact circular-segment area instead.
• Consistent winding. Outer loops are forced CCW and holes CW, so extrusion, area and DXF output all agree on what is solid and what is a hole.
• Trim against true intersections, not against rendered pixels — so trimming stays correct at any zoom.

Draft v3.0 — DXF editor + viewer (draft.html)

A second tool in this repo: open an existing DXF/DWG (or a STEP/IGES/STL/OBJ model), edit it and save DXF again. Live: https://gervdalius-droid.github.io/cad/draft.html

• Edit — move, copy, rotate, scale, mirror, stretch, offset, trim, chamfer, fillet (also replaces existing fillets; R0 = sharp corner), join/explode, grips, exact sizes in the panel.
• Sheets with parts — detects the sheet and every part (including parts nested in cutouts), drag parts with snapping, R rotate / F flip, overlap / off-sheet / gap warnings, auto-arrange.
• Viewer — distance/angle dimensions, holes by diameter, cut length, open-contour warning; 3D STEP/IGES/STL/OBJ with measuring and projection to DXF (straight into the 2D editor).
• Files — DXF (any version) and DWG (blocks, splines, ellipses included); drawings in inches/cm/m are converted to mm. Saves DXF R12 or a complete DXF 2000 (LWPOLYLINE) that AutoCAD-strict readers accept.
• Checks before cutting — duplicate / overlapped lines (would be cut twice) with one-click removal, open contours, parts overlapping or too close.
• Feels like CAD — type values at the cursor (50, 600,400, #0,0, 100<45), Tab cycles snap points, Ctrl+C/X/V (also between tabs), Ctrl+D, arrows nudge, click again to pick the object underneath, right-click menu, ? for all keys. Stays smooth on sheets with thousands of parts.

Run it

python3 serve.py          # http://localhost:8752/
python3 serve.py 9000     # different port

Tests: http://localhost:8752/test.html — 72 checks covering geometry, loop detection, export and the UI itself. No runner to install; it's a page you open.

Built with

Vanilla JavaScript, HTML Canvas, no dependencies, no build step. ~1,800 lines.