DXF to SVG

Why people turn DXF into SVG

SVG is the vector format of the web, and plenty of design and cutting software opens it too. Converting a DXF gives you the same geometry in a file that a browser, an illustration app or laser software can use without a CAD import step.

• Laser cutting and engraving: part outlines drawn in CAD, ready for software that prefers SVG.
• Vinyl cutters and pen plotters, for signs, stencils and templates.
• Websites and documentation: a floor plan, a wiring layout or an exploded view that stays crisp at any zoom, with text that can be selected and searched.
• Illustration apps, to recolour layers or tidy a technical drawing for a manual, a poster or a slide.

Nothing is sent to a server along the way. The SVG is written in this tab, so a client's part drawing stays with you.

How to convert DXF to SVG

1. Choose Lines above the drop area: Visible for screens and documents, Hairline (laser) for cutting. Visible is already selected.
2. Drop your .dxf files here, or use Choose file. 5 files convert at a time.
3. When the row says your file is ready, select Download. For several files, Download all (.zip) bundles them.
4. Look at What changed under the file for anything that was approximated or left out.

The Lines setting is taken when a file is added. To compare both styles, convert the same drawing once with each.

Read the table with your use in mind. For a laser, the line types and line weights that aren't converted rarely matter: a cut line is a cut line, and here every line has the same width. For documentation they do matter, because dashed hidden lines and centre lines arrive solid.

Text is where SVG and PDF differ most. Every character comes through, Greek letters and the diameter sign included, because SVG text is Unicode. The font is up to whatever opens the file: we ask for Arial, then Helvetica, then any sans-serif, so a drawing set in a CAD stroke font (SHX) will look a little different. Pattern hatches arrive as a light tint with an outline, which matters if you're cutting; there's more on that below.

Visible or Hairline lines

Visible draws lines 0.25 mm wide at real size, or wider on a big drawing. The width grows with the drawing so that lines stay about a pixel wide when the whole drawing is fitted to a screen around 1600 pixels across. A part the size of an A4 sheet keeps 0.25 mm; a 30 × 40 m floor plan gets lines about 31 mm wide, which is what you want once it's shrunk onto a web page.

Hairline makes every line 0.01 mm, however large the drawing. Some laser drivers and cutting workflows treat a hairline stroke as a cut line, and it's a clean start if you'd rather set stroke widths yourself. In a browser, hairlines can look faint or vanish when you zoom out; zoom in and they come back.

Neither setting moves a single point. Only the stroke width changes.

Real scale, units and layers

The SVG's width and height are written in millimetres, worked out from the units the drawing declares: inches, feet, millimetres, centimetres or metres. Software that reads SVG units can open it at its true size, though it's worth measuring one known feature after import. If the drawing declares no units, we assume millimetres and say so in What changed.

Inside the file, coordinates stay in drawing units, shifted so the lower-left corner of the drawing sits at 0,0. That keeps survey drawings with very large coordinates on the canvas, but the original coordinates aren't carried over.

Entities are grouped by layer, in drawing order. Each group carries the layer's name in its class and in a data-layer attribute, so a stylesheet or a script can find it. When a drawing goes back and forth between layers, one layer can appear in several groups. Colours come from the drawing, with very light ones darkened so they show on white.

An SVG is plain, uncompressed text, so a big drawing makes a big file. In our measurements, a 20 MB synthetic test drawing became a 43 MB SVG; the same drawing as a PDF was 7.5 MB.

Getting a DXF ready for the laser

• Freeze or turn off the layers you don't want cut, such as dimensions, notes and hatching, before saving the DXF. Frozen, hidden and non-plotting layers are left out of the SVG.
• Pattern hatches come through as a tinted area with a closed outline, and that outline will cut. Delete the hatch, or keep it on a layer you turn off. Solid hatches arrive as filled shapes, which some laser software engraves.
• Text arrives as live text. If your laser software needs outlines, convert the text to paths in your design app first, and check that the font looks right.
• Dimensions arrive as lines, arrowheads and text, and leaders as plain lines without arrowheads. All of them will cut unless their layers are off.
• Measure one known feature after import, to be sure the scale is right before the first cut.

If the SVG isn't what you expected

• Lines are invisible or very faint. Hairline lines are 0.01 mm wide. Zoom in, or convert again with Visible.
• The size is off by 25.4, or by 1000. The drawing's units are missing or don't match how it was drawn. An inch drawing with no units comes out 25.4 times too small; a drawing made in metres but labelled millimetres comes out 1000 times too small. Fix the units in your CAD app and save the DXF again.
• The file is slow to open. Large drawings make large SVGs. For viewing and sharing, DXF to PDF packs the same drawing into a much smaller file.
• Text looks different from CAD. The font is replaced, and width factor and slant aren't applied. Text sits where the drawing puts it, but the letter shapes differ.
• Something is missing. Layouts, hidden layers and external references aren't drawn. What changed lists what was left out, and What we draw explains each case.
• An error instead of an SVG. Binary DXF, DWG files, damaged files and drawings with too much detail are covered in When a DXF won't convert.

Try it with a sample file

sample-cad-entities.dxf (190 KB) is a test sheet from the open-source dxf library, with separate panels for lines, arcs, splines, hatches, text, blocks, leaders and six kinds of dimension. It's MIT-licensed, and the notes on our sample files say where it comes from.

Convert it twice, once with each Lines setting, and open the two files side by side. Then find the line of special characters: unlike the PDF version, the SVG keeps ≈, Δ, π and Ω. The drawing declares no units, so What changed will tell you millimetres were assumed.