Free OBJ to STL converter
Convert OBJ to STL for your slicer.
Most slicers accept STL first. Drop an OBJ from Blender, a scan or a model library and get a binary STL ready to slice.
Why convert OBJ to STL?
3D-printing workflows are built around STL. Converting an OBJ also strips texture references and materials a printer doesn't need.
How to convert OBJ to STL
- Choose your OBJ file above, or drag it onto the box.
- Check that STL is selected. You can switch to any other output.
- Select Convert. The file downloads straight away. Nothing is uploaded.
Good to know
- Quads and polygons are triangulated.
- Check the scale in your slicer. OBJ files from art tools are often in metres or arbitrary units, while slicers assume millimetres.
What converts, and what doesn't
- Every output is a triangle mesh. STEP and IFC solids are tessellated for display, so the result is not an editable solid or B-rep.
- When the source names its parts (STEP and IFC assemblies, for example), they become named groups in OBJ. STL, PLY and GLB hold a single combined mesh.
- Colours and materials are not carried over.
- Coordinates keep the source units, except GLB, which is scaled to metres when the source declares its units.
Frequently asked questions
Are textures kept?
No. STL can't store textures or colours, so only the geometry is converted.
Is my file uploaded?
No. The file is read and converted by the Caddis engine running inside your browser tab. It is never sent to a server, so confidential drawings stay on your device.
Is it really free?
Yes. There's no account, watermark, page limit or daily quota. The converter runs on your own computer, so it costs us nothing per file.
Need to measure or mark up the drawing too?
The same engine powers the free Caddis viewer on the web and on iPhone. Open DWG, DXF, STEP and STL files, measure, and add markup, all on your device.
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