Convert OBJ to STL.
Convert an OBJ 3D model to STL. The standard format for 3D printing and slicers. Geometry preserved exactly.
Inside The Conversion
See The Input. Inspect The Result.
A real OBJ to STL conversion using a sample file. Compare the files below, then use the converter above with your own file.
Recorded Sample
Converted on the server in this run.
harbour-lane-doughnut.obj
harbour-lane-doughnut.stl
Previews show the sample files from this recorded conversion. Choose Input or Result to focus on one file.
View The Original Run Capture
A screenshot of the completed run, preserved in its original theme. The comparison above adapts to your current theme.
OBJ to STL, ready for the slicer
OBJ is a common editing and interchange format. It can carry materials, UVs and texture references alongside the mesh. STL is what 3D-printing slicers like Cura, PrusaSlicer and Bambu Studio expect: just the geometry. Converting an OBJ you've modelled or downloaded to STL is the step that makes it printable.
Geometry only
STL keeps just the triangle mesh: any materials, colours or UV coordinates the OBJ carried are dropped, since a slicer works purely from the shape. Multi-part models are merged into a single mesh for a clean result.
Watch for non-manifold geometry
Before printing, make sure the mesh is watertight: holes, flipped normals or non-manifold edges can confuse a slicer. Most slicers and tools like Meshmixer or Blender can detect and repair these. Keep the original OBJ for editing if you'll keep refining the model.
How it works
- 01
Upload your OBJ
Drop a 3D model or pick one from your device. Private by default.
- 02
Convert with trimesh
trimesh reads the geometry and writes STL, vertices and faces preserved exactly, no paid API in the loop.
- 03
Download
Grab your STL.
Geometry preserved exactly, vertices & faces
Watertight meshes stay watertight
Private uploads, auto-deleted after 1 hour
No watermark, no signup to try
Free and open-source engine (trimesh)
OBJ to STL
This converts the 3D geometry from OBJ to STL. Vertices and faces carry over; support for colour, materials and textures depends on the target: STL keeps more scene data.
Common questions
Is it free?+
Yes. Convert OBJ to STL free. No signup and no watermark. Free covers 10 server conversions a day, up to 100 MB a file. Pro removes the daily limit and raises the file limit to 2 GB.
Is my model private?+
Uploads go to a private bucket, are converted, and auto-delete after 1 hour. Files never touch a third-party converter.
Is the geometry changed?+
No. Vertices and faces are preserved exactly. Multi-part scenes are merged into a single mesh for clean output.
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