SVG vs DXF: which file for cutting, lasers and CNC
SVG and DXF are both vector files. SVG keeps colours, fills and layers and suits Cricut and lasers. DXF is bare outlines from CAD and suits CNC and plasma.
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SVG and DXF are both vector formats: each stores a drawing as lines and curves, not pixels, so a machine can follow the outlines. The difference is where they come from. SVG is a graphics format made for the web, and it keeps colours, fills, line widths and grouping. DXF is an exchange format from the world of CAD, and in practice it carries bare geometry sorted onto layers. For a Cricut, choose the SVG. For CNC routers, plasma tables and most CAD and CAM software, DXF is the usual choice. Many lasers take either.
Side by side
| SVG | DXF | |
|---|---|---|
| Stands for | Scalable Vector Graphics | Drawing Exchange Format |
| Comes from | The web: a W3C standard | CAD: created by Autodesk for AutoCAD |
| Written as | XML text | Text in numbered code pairs, or a binary form |
| Fills and colours | Yes: fills, strokes, gradients | Outlines with a colour number or layer. Filled areas exist mostly as CAD hatches, which cutting software generally ignores |
| Line width | Yes | Rarely used by cutting software |
| Curves | Bézier curves and arcs | Lines, arcs, circles and splines, depending on the version written |
| Units | Can state mm, cm or inches | Bare numbers. A header may say which unit, and often does not |
| Y axis | Down from the top | Up from the bottom |
| Opens in a web browser | Yes | No |
| Usual home | Cricut, Silhouette, lasers, plotters, web pages | CAD, CAM, CNC routers, plasma and waterjet cutters, lasers |
Which to choose
Cricut. SVG. Design Space reads both on a computer, but an SVG arrives with its colours, and Design Space sorts layers onto mats by colour, so a multi-colour design is ready to cut. A DXF has no fills to carry that. On a phone or tablet the choice is made for you: Design Space there takes SVG and not DXF.
Silhouette. It depends on the edition of Silhouette Studio. Silhouette’s own software page says that opening an SVG needs Designer Edition or higher. The free Basic Edition opens DXF, which is why so many cut file downloads include one. Opening an SVG in Silhouette Studio has the details.
Laser cutters and engravers. Laser programs such as LightBurn import both. SVG is the easier of the two when colours are used to separate cutting from engraving, and when the file states its size in millimetres. DXF is the natural choice when the part was drawn in CAD.
CNC routers, plasma and waterjet. DXF. CAM software is built around CAD drawings, and many programs in that world do not read SVG at all, though some hobby programs do. An SVG will not behave the same as a DXF there: even where it opens, fills, stroke widths and text mean nothing to a tool path. Convert it and check the result.
Pen plotters. SVG, as a rule. Plotter tools such as vpype and the AxiDraw software work from SVG.
A web page, or a file to edit later in Inkscape or Illustrator. SVG.
What is lost going from SVG to DXF
A DXF made for cutting holds outlines and little else. Converting an SVG to one drops whatever is not an outline:
- Fills. A filled shape becomes its edge.
- Stroke width. A thick line becomes its centre line.
- Text. Unless it was converted to paths first, lettering is usually dropped or replaced.
- Embedded pictures, gradients, clipping and masks.
- Smooth curves, often. Many converters write curves as chains of short straight lines, since that is the form the widest range of machines accept.
The SVG to DXF page works this way and says so. It writes every shape as a polyline in millimetres, keeps curves within a tolerance you set (0.05 mm unless changed), and can put each colour on its own layer so that cut lines and engraving lines stay apart. Text has to be converted to paths in a drawing program first.
What changes going from DXF to SVG
Little is lost, since SVG can describe the lines, arcs and curves of a flat DXF drawing. What shows up is how tidy the drawing was.
- Separate pieces. CAD drawings are often a heap of single lines and arcs that only look joined. A cutter wants closed shapes.
- No fills. Every shape arrives as an outline.
- Unknown units. If the DXF does not state its unit, the converter has to assume one.
- Text and hatching. These are stored in CAD’s own way and often do not come across.
The DXF to SVG page writes arcs and circles as true SVG arcs, turns each DXF layer into a group, can join lines that meet end to end into closed paths, and lists what it left out, text and hatches among them. It reads the text form of DXF, not the binary form or DWG.
Size: where both go wrong
DXF. The numbers in a DXF have no unit of their own. A drawing made in inches and read as millimetres comes out 25.4 times too small, and the reverse 25.4 times too big. When a program asks for the units on import, the answer matters.
SVG. An SVG can state a real size, as in width="100mm", and then most programs agree. A size in bare pixels is less certain: the standard is 96 pixels to the inch, but programs have also used 90 and 72, so the same file can arrive a few percent or a third out. SVG size and units explains how to state a size that survives.
Whichever format is used, measure something of known length after importing, before cutting.
Common problems
| What you see | Cause | Fix |
|---|---|---|
| The DXF is about 25 times too big or small | Inches read as millimetres, or the reverse | Choose the right unit on import, or rescale by 25.4 |
| The cutter stops and starts, or will not fill a shape | The DXF is made of separate lines, not closed shapes | Join the ends in CAD, or convert with joining switched on |
| Shapes appear that were hidden in the SVG | A DXF has no fills, so nothing covers anything else | Delete the shapes that are not wanted |
| Lettering is missing | Text was not converted to outlines | Convert text to paths, then export again |
| Curves look faceted | The converter wrote them as straight pieces with a coarse tolerance | Convert again with a finer tolerance |
| Design Space will not take the DXF on an iPad | The mobile apps take SVG only | Use the SVG, or convert the DXF to SVG |
| Every piece is the same colour | The DXF carried no colours | Recolour the layers in the cutting program |
Questions
What is the difference between SVG, PNG and DXF? SVG and DXF are vectors: outlines a blade or beam can follow. PNG is a grid of pixels, which a cutting program has to trace before it can cut, or print for Print Then Cut. SVG vs PNG covers that pair.
Is one more accurate than the other? Both store coordinates as numbers, to as many decimal places as the program writes. Accuracy is lost in conversion, when curves are cut into straight pieces, not in either format itself.
Why do cut file downloads include both? So that the same purchase works in Design Space, in every edition of Silhouette Studio, and in other machines’ software.