SVG to DXF — Chained Polylines, Correct Units
For when the last DXF imported as thousands of disconnected line segments, opened at the wrong size, or sent the laser jumping across the bed. Each path comes out as one continuous polyline, in the units you asked for.
How to Convert SVG to DXF Without Loose Line Segments
Drop in an SVG and pick your output units — millimeters or inches. The converter walks every path, rect, circle, ellipse and polygon, flattens all transforms, and writes the result as R12 DXF (AC1009), the version every laser and CAM program reads.
Each path in your artwork comes out as one continuous POLYLINE entity, not a pile of separate lines. That is the difference between a laser that follows your outline and one that lifts and travels between every segment. Closed shapes keep their closed flag, so fill and offset work instead of being silently ignored. True circles are written as real CIRCLE entities rather than segmented, so holes stay round.
The unit flag $INSUNITS is written on every file — 4 for millimeters, 1 for inches. Most converters leave it blank, which is why a 10-inch part lands in Fusion 360 at 10 mm. SVG groups become DXF layers so you can set separate speed and power per layer in LightBurn, and within each layer the paths are ordered by proximity to cut down travel moves before the file ever reaches your machine.
All of it runs in this browser tab. The SVG is parsed and the DXF is built on your own machine — the design is never uploaded, which matters when the file is a client's product or a design you are about to sell.
Why Your DXF Imports Wrong — and What to Check
- Your last DXF imported as thousands of disconnected line segments, and Auto-Join (Alt+J) won't stitch them
- The laser is cutting out of order — crazy travel moves across the bed, and Optimization Settings can't fix it because there are no paths to order
- LightBurn is ignoring fill on shapes that look closed on screen
- A design opened tiny in Fusion 360, or came in at the wrong size, because the file carried no unit flag
- Circles came out faceted — flat edges instead of curves when you zoom in
- Converting artwork from Illustrator, Inkscape, or Figma for laser cutting, CNC routing, or plasma
| Software | Units on import | What to check first |
|---|---|---|
| LightBurn | Confirm the import matches your workspace units | Cuts / Layers panel — one row per SVG group, not hundreds |
| Fusion 360 | Insert DXF dialog, units dropdown | Measure a known edge before you extrude |
| Ruida controllers (RDWorks) | Millimeters — export mm from this tool | Closed shapes show as fillable, not outline only |
| Inkscape | Confirm scale after import | Curves read as single paths, not loose segments |
Mistakes That Break a DXF at the Machine
- Leaving text as text — convert to outlines first (Illustrator: Type → Create Outlines; Inkscape: Path → Object to Path). Text elements are skipped, not converted
- Expecting embedded photos to convert — DXF is vector-only; trace images to paths before converting
- Using Draft quality for detailed work — curves become visibly faceted; Standard (0.1 mm) is right for most laser work, Fine (0.02 mm) for jewelry and inlay
- Assuming a shape is closed because it looks closed — a path with a visible gap in the SVG comes out open, and no converter can guess where you meant it to join. Close it in your design tool first
- Designing with fills instead of strokes — a filled shape exports as multiple nested outlines, so you get the fill boundary and every stroke edge as separate paths
- Not checking units on import — this tool writes the unit flag, but your machine software can still be set to override it
Why does my DXF import as thousands of separate lines?
Because the converter that made it wrote every segment of every curve as its own LINE entity instead of chaining them. Your laser software sees ten thousand unrelated objects and cannot order them into a cut path. This tool writes one POLYLINE per path in your artwork, so there is nothing to join in the first place.
Why does my DXF import as thousands of separate lines?
Because the converter wrote every segment of every curve as its own LINE entity and rounded the coordinates on the way out. The second half is what actually breaks the file. LightBurn will stitch loose LINE entities back together on import when their endpoints land on the same point — we fed it a square drawn as four unconnected lines and it arrived as one closed shape. What it will not stitch is endpoints that miss each other by more than 0.01 mm, and a segment-per-line export at low decimal precision misses by far more than that.
So the file that arrives in ten thousand pieces is not just chopped up — it is chopped up and slightly misaligned. This tool writes one POLYLINE per path in your artwork, so the segments were never separated and there is nothing to rejoin.
Why is my laser cutting out of order and traveling all over the bed?
LightBurn's Optimization Settings can only order paths it can recognize as paths. Given loose line segments it has nothing to sort, so the head wanders. Files from this tool arrive with each layer's paths already ordered by proximity, and with real polylines for LightBurn to optimize further.
Why won't LightBurn fill my shape?
Fill needs a closed path. If the shape is open — even by a fraction of a millimeter — LightBurn will happily cut the outline but skip or mangle the fill. This tool preserves the closed flag from your SVG, so a shape that is closed in your design file arrives closed in the DXF.
Why did my DXF open tiny in Fusion 360?
The file had no unit information, so Fusion assumed millimeters and your 10-inch part became 10 mm. The DXF header here always carries $INSUNITS — 4 for millimeters, 1 for inches — set from the toggle you pick before converting.
Why do my circles look like polygons?
Zoom in far enough on most converted DXFs and circles turn into stop signs, because the curve was approximated with too few points. True circles in your SVG are written here as DXF CIRCLE entities, which stay mathematically round at any zoom. Other curves are approximated to the tolerance you choose — 0.1 mm on Standard, which is finer than a laser kerf.
Do curves stay as curves in the DXF?
Not as splines, and no R12 file can do that — the format has no spline entity, which is also why R12 is the version everything opens. Beziers are approximated as polyline points at your chosen tolerance. The part that matters for cutting is that those points stay chained into one entity rather than scattered into separate lines.
Will my layers survive the conversion?
Yes. Each top-level group in your SVG becomes a named DXF layer, using the Inkscape label or the group id, so you can assign separate speed and power settings per layer. Turn off "Preserve layers" to flatten everything onto layer 0.
What DXF version does this export?
R12, header AC1009. It is the most widely supported DXF version — LightBurn, Fusion 360, RDWorks, AutoCAD, Inkscape and every CAM package read it without complaint.
Does my design get uploaded anywhere?
No. The SVG is read and the DXF is built inside your browser tab. The file never touches a server, which is the difference that matters when the artwork belongs to a client.