Convert STL to DXF
A DXF is flat and an STL is not, so this is not a conversion in the usual sense — something has to be thrown away, and you choose what. Take the outline of the model seen down one axis, or cut it with a plane and draw the cut. Both come out as an R12 DXF that any cutting machine will read.
Drag a 3D file here, or.
This page is set up for STL files. Other formats we can read work here too.
The file is read on your own computer. It is never uploaded.
Your file is read by your own browser and never sent to a server. There is no upload, no account and no copy of your model anywhere but on your computer.
Two different drawings, and which one you want
An outline is the shape of the model’s own shadow, looking straight down one axis. This is what you want to cut a backing plate for a part, to draw round it, or to make a pocket it drops into.
A cross-section is what you get by slicing the model with a flat plane and drawing the cut. This is what you want for a profile, a template, a gasket, or the footprint a part actually sits on. The slider sets where the plane goes, from the bottom of the model to the top.
They are genuinely different answers and neither is more correct. A cone’s outline is a circle; a cross-section halfway up the cone is a smaller circle. Choose in the box above the button and watch the drawing change.
Why the output is R12
DXF has had a dozen versions since 1982, and cutting machines have not kept up. The controller on a laser or a plasma table is frequently older than the part being cut, and R12 is the version all of them read. The newer versions add object handles, a class table and an OBJECTS section — none of which carry any geometry, and any one of which can make an older importer reject the file.
So the file written here is deliberately plain: a header with the units in it, one layer, and a list of polylines. It opens in AutoCAD, LibreCAD, QCAD, Fusion 360, LightBurn, Inkscape and every CAM tool worth naming.
The outlines are written as paths with no fill, because a filled shape is ambiguous about whether the machine should follow the edge or clear the middle out, and a plain path is not.
Units are written into the file, unlike in an STL
An STL does not record what one unit means. A DXF does, in a header field, and this converter writes it. So the one piece of information that the STL was missing gets added on the way out, and your CAM software opens the drawing at the right size instead of guessing.
Set the output unit box to whatever your machine works in. If the STL itself was in the wrong units — the usual case is a model exported from CAD in inches — set the input unit box too, and check the width and depth figures beside the 3D view before you download.
What a cross-section can and cannot give you
On a watertight model every cut comes back as a closed loop, which is what makes the result usable as a cutting path rather than a picture. On a model with holes in its surface, the cut can come back as open chains, and a cutting machine will not know what to do with those.
If that happens, run the model through the STL repair tool on this site first and take the section from the repaired version. The health report will tell you straight away whether the model is watertight, which is the same question.
What survives, and what does not
Kept in the DXF file
- The exact outline or section, at the model’s true size
- Holes and internal openings, as separate closed paths
- A stated unit, which the STL never had
Lost on the way
- The third dimension — this is the whole nature of the conversion
- Any surface detail that does not reach the cutting plane
- Colour and part names, neither of which an STL had anyway
How to convert STL to DXF
Drop the .stl file in
The model appears in the 3D view. Check the width, depth and height look right before going any further.
Choose outline or cross-section
Outline for a shadow of the whole model. Cross-section for a cut at one height. The drawing is rebuilt as you switch.
Pick the axis, and the height if you are cutting
Looking down Z gives the footprint, which is what a backing plate or a pocket needs. The height slider runs from the bottom of the model to the top.
Set the output unit to what your machine uses
It is written into the DXF header, so your CAM software opens the drawing at the right size rather than assuming one.
Download and check it in your CAM software
Measure one known dimension before you cut anything. That one check costs ten seconds and saves a sheet of material.
STL and DXF compared
| Property | STL.stl | DXF.dxf |
|---|---|---|
| File contents | Binary or plain text. Binary is an 80-byte header, a triangle count, then 50 bytes per triangle. | Plain text in numbered group codes, with a binary variant nobody uses. |
| Geometry | Triangles only. Curves are approximated when the file is made, and cannot be recovered. | Lines, arcs, circles, polylines and splines, in 2D and limited 3D. |
| Units | None. The file stores bare numbers, and every reader has to guess what they mean. | Recorded in a header variable, as one of twenty-odd unit codes. |
| Colour and texture | None. There is no place in the format for a colour, a material or a texture. | A colour number per entity, and colour by layer. |
| Separate objects | One body. Several parts written into one STL become one undivided lump of triangles. | Named layers, plus blocks for repeated geometry. |
| Published by | 3D Systems, 1987, for the first stereolithography machines. | Autodesk, 1982, as the published counterpart to the closed DWG. |
| Written by | Every CAD program and every slicer, as the common denominator. | AutoCAD, LibreCAD, QCAD, Fusion 360 and every laser cutter’s software. |
Questions
- Will my laser cutter software open this?
- Yes. It is written as an R12 DXF, which is the version LightBurn, LaserGRBL, RDWorks, Fusion 360 and every older machine controller read. Newer versions add nothing this drawing needs and are the usual reason an older controller rejects a file.
- Can I get a DWG instead?
- No, and no free tool can write one. DWG is AutoCAD’s own format and writing it needs a paid membership of the Open Design Alliance. Every program that reads a DWG also reads a DXF, so in practice this is the same thing with a different extension.
- My cut came out as open lines rather than closed shapes.
- The model has holes in its surface, so the cutting plane found chains rather than loops. Run it through the STL repair tool first and take the section from the repaired model.
- Should I use SVG or DXF for my laser cutter?
- DXF if your software takes it, because the file states its units and an SVG only implies them. Both are offered here from the same model, so try the one your software prefers.
- Is my model uploaded anywhere?
- No. Everything happens in your browser. The file is never sent to a server and there is no account.
Having it cut
If you do not have a machine, these will cut this drawing from sheet material and post it to you. Upload the file you just downloaded; all three quote from it directly.
- SendCutSendLaser-cut sheet metal and plastic, no minimum order
- PonokoLaser cutting in acrylic, wood and card, single pieces
- PCBWayCNC machining and sheet metal from a drawing
These are ordinary links, not paid referrals — we earn nothing if you use them. The converter above is the same whether you do or not.
Where to go next
The other direction
Other things to do with a STL file
Other ways to get a DXF file
Related guides and tools
- Gridfinity generatorBins and baseplates, any size, built in the browser
- Turn text into an STLType a word and print it, without drawing anything
- Turn an image into an STLA photo or a logo, turned into something you can print
- Lithophane generatorA photo printed as thickness, lit from behind
- Repair an STL that will not sliceClose the holes and separate the bad edges so a slicer accepts it
- STL to G-codeGuide
- How to convert an STL file to G-codeGuide
- Convert DWG to STLGuide
- Convert STL to DWGGuide