STL to OBJ Converter
Drop a print-ready STL, get a Wavefront OBJ ready for Blender, Maya, ZBrush, or any DCC tool. Triangle counts and topology preserved exactly.
Drop your STL file here
Converts to .obj — stays on your device
Why convert STL to OBJ?
- Importing a Thingiverse or Printables download into Blender for retopology before reprinting it.
- Bringing a scanned STL into ZBrush for sculpt cleanup before generating a final printable.
- Editing a customized OpenSCAD/Tinkercad export in Maya where the team's pipeline is OBJ-native.
- Converting a parametric STL from Fusion 360 into OBJ for a game-engine asset pipeline.
- Splitting a multi-part STL into named groups in Blender for separate texture work.
- Adding UV coordinates and materials to a print model in a DCC tool before exporting to GLB.
How our converter works
Your STL is parsed by three.js's STLLoader (handles both ASCII and binary STL automatically) into a BufferGeometry — a tightly packed array of vertex positions and normals. We wrap it in a Mesh and run it through three.js's OBJExporter, which emits standard Wavefront OBJ text: `v` lines for vertices, `vn` for normals, `f` for faces. Triangle count and geometry are preserved exactly. The conversion runs entirely in your browser.
Frequently asked questions
Will the output open in Blender?
Yes — the OBJ output follows the original Wavefront spec, which Blender, Maya, ZBrush, 3ds Max, and Cinema 4D all import natively. Drop the .obj into the file menu or drag it onto the viewport.
Are normals preserved?
Yes — STL stores per-face normals, OBJ supports per-vertex normals, and three.js's exporter writes `vn` lines for each. If your downstream tool needs smooth shading, recompute normals there.
What about materials or colors?
STL has no material concept, so the OBJ output is geometry-only — no .mtl sidecar is emitted. The receiving DCC tool will assign a default material on import.
Does it handle multi-megabyte STL files?
Up to a point — the limit is your browser's available memory. A 50-100MB binary STL converts in a few seconds on modern hardware. Larger files (300MB+) may hit memory constraints on mobile.
Are my files uploaded?
No. STLLoader, OBJExporter, and the file I/O all run as JavaScript on this page. Proprietary geometry, scanned models, and unreleased product designs stay on your device.
About the STL format
STL (Stereolithography) is the format every 3D printer slicer reads. It's intentionally minimal — a list of triangles with surface normals, no materials, no colors, no anything else. The simplicity is the point: STL is for fabrication, where the only question is 'where is the surface,' and slicers convert it to G-code via marching planes. OBJ (Wavefront) is the text format that became the de-facto interchange between 3D content tools in the 1990s and never went away. It supports vertex normals, UV coordinates, and material references via .mtl sidecars. Converting STL→OBJ is what you do when a print-ready model needs to travel into a DCC tool for editing — preserving the geometry while making it available in a format Blender or Maya wants to read.