STL to SVG Converter
Turn a 3D model into a flat vector outline your laser or router can cut.
Built and maintained by Matúš Koleják, Co-Founder, TechDraw AI
Updated
Drop a file here. It never leaves your browser.
No sign-up · no upload · no watermark · true millimetres · DXF, DWG, PDF one click away
Want the whole 3D model instead? STL to 3MF · Broken mesh? STL repair
How to convert an STL to SVG
Add your STL
Drop an STL onto the tool, or click to choose one. It is read in your browser and never uploaded.
Put the cut where you want it
Pick the plane — Z for a plan view, Y or X for a front or side — and drag the slider through the model. The outline redraws live, with the enclosed area in mm² underneath.
Download SVG
Click Download SVG. It comes out in true millimetres, holes included, ready to cut. DXF, DWG, PDF are one more click.
What happens to your file
Going from three dimensions to two throws information away, and the only honest question is which information. This tool takes a plane section: it walks every triangle, finds the ones the plane passes through, works out the exact segment where each one crosses, and chains those segments into closed outlines. The result is real geometry rather than a trace of a picture, so a circular hole comes back as a smooth closed loop at the size it was modelled, not as a ragged polygon recovered from pixels.
Holes fall out on their own. A bore through a part crosses the plane just as the outside does, and because its surface faces inward its loop winds the opposite way, which is exactly what CAD and every cutter expect for an island. That is also why the area shown under the drawing is the material a cutter would actually remove: the holes subtract themselves.
What it will not do is guess. There are infinitely many flat sections through a solid and only you know which one you meant, so the plane is a slider rather than a decision made on your behalf. And if the mesh is open where the plane runs, the outline cannot close; those chains come back in red and are written on their own layer rather than quietly patched, because a profile that looks closed and is not will fail on the machine instead of on the screen. Starting from a photo or a drawing rather than a mesh is a different job entirely — that is the image to DXF converter.
About formats
STL (from 'stereolithography', though the letters are also read as 'Standard Tessellation Language') was created by Chuck Hull at 3D Systems in 1987 for the first commercial stereolithography machine, and it has outlived nearly everything else from that era. The format describes a shape in the simplest way a shape can be described: as a list of triangles, each one given by three corner points and the direction its outward face points. There is no notion of a curve, so a cylinder is a fan of narrow flats and the smoothness depends entirely on how many triangles were spent on it. There is no colour, no units, no layers, no history and no way to say that two triangles belong to the same feature. That poverty is exactly why it survived: any program can write it and any program can read it, so it became the neutral handoff between modelling and printing. Files come in two flavours, a human readable ASCII form and a compact binary form that stores each triangle in fifty bytes, and the binary one is what practically everything writes today because the ASCII version runs several times larger. The one thing a printer genuinely needs from an STL is that the surface be closed, meaning every edge is shared by exactly two triangles so the solid has a well defined inside; a mesh with gaps leaves the slicer guessing where the material goes. Units are the standard trap, since the file carries none and every slicer simply assumes millimetres.
- Developer:
- 3D Systems
- Initial release:
- 1987
Frequently asked questions
How do I convert an STL to SVG?
Drop the STL onto the tool on this page. It is read in your browser and cut with a flat plane, and you get the outline straight away. Move the slider to put the cut where you want it, then click Download SVG. DXF, DWG, PDF come off the same cut with one more click. No account, nothing uploaded.
Is this STL to SVG converter free?
Yes. Free, no watermark, no file size limit, and no account needed to convert or to download. There is no paid tier of this tool to upsell you to.
Is my file uploaded anywhere?
No. The STL is opened by code running in your browser tab and never sent to a server, so nothing is stored, logged or scanned. You can disconnect from the internet once the page has loaded and it keeps working.
What exactly am I getting: a section, a shadow, or a flattened surface?
A section. One flat plane passes through the solid and you get the exact curve where the surface crosses it, holes and all. It is not a shadow: projecting the whole model flat and outlining what you see is a different operation, and on any part with an overhang it returns a shape that exists nowhere on the object. It is not an unfold either: nothing here flattens a curved surface into a development, which is a sheet-metal operation and only has an answer for surfaces that are developable in the first place.
I have a flat part modelled in 3D and I want to laser cut it. Is this the right tool?
Yes, and it is the case this is built for. A plate, a bracket, a gasket or a panel that was modelled as a solid has the same profile at every height through its thickness, so a cut anywhere in the middle is exactly the outline you need, including every hole. Leave the axis on Z, drag the slider to the middle, and download. The result is exact geometry, not a trace of a picture.
Does it come out at the right size?
Yes. STL carries no unit and every slicer and CAD program reads it as millimetres, so that is what the outline is written in. The DXF declares millimetres in its header, the SVG is sized in real millimetres with a matching viewBox, and the PDF is drawn to scale. A 40 mm part arrives as 40 mm on the bed rather than needing to be scaled by eye.
My outline has red lines in it. What does that mean?
The cut ran off an open edge, so the outline could not close into a loop. That is the mesh being broken rather than the cut being wrong: a watertight model gives closed loops at every height. Those red chains are still written to the file, on their own layer, so you can see where the problem is instead of getting a silently incomplete profile. Running the file through the STL repair tool first usually closes them.
Can I get the outline of the whole object, not just one height?
Not from a single cut, and that is honest rather than a limitation being hidden. A 3D object has infinitely many flat sections and no two need to look alike. If your part varies with height, take the cut where the feature you care about is; the slider is there so you can see each one rather than guess. If you genuinely need the silhouette of the whole thing, that is a projection problem and a different tool.
Which programs open the SVG?
Any of them. LightBurn, Glowforge, xTool Creative Space, Inkscape, Illustrator, Affinity, Cricut Design Space, Easel and X-Carve all read SVG directly, and the millimetre sizing means it lands at the modelled size instead of an arbitrary one.
Is there a file size limit?
None imposed by the tool. Cutting is a single pass over the triangles with no spatial index, so half a million triangles re-cut in about fifteen milliseconds and the slider stays live. The practical limit is your own machine's memory, since the file is held in the browser tab.