STL · OBJ
STL vs OBJ
STL is the printing workhorse; OBJ is the editing format. The difference is not quality but what each file carries: triangles alone versus geometry with UVs, normals and material references.
| Criterion | STL | OBJ |
|---|---|---|
| What it stores | Triangles, binary or ASCII | Vertices, faces, UVs, normals and groups |
| Units | None; slicers assume millimetres | None |
| Colours and materials | None | Material names in a separate MTL file |
| Scene structure | Shells without names | Named groups and objects |
| Best for | Sending a mesh to a slicer | Editing and rendering in Blender, Maya or ZBrush |
| File size | Compact binary | Larger text file, plus MTL and textures |
In short. Print with STL, edit with OBJ. Converting STL to OBJ keeps the geometry; converting OBJ to STL drops materials and UVs. If you need colours, keep the MTL with the OBJ, or use GLB.
Convert between them
Format pages
Questions
Can I convert STL to OBJ?+
Yes, geometry only; colours and UVs cannot be invented from an STL.
Which is better for 3D printing?+
STL or 3MF: slicers read them directly and ignore OBJ materials.
Does OBJ keep colours?+
Only through a companion MTL file and textures; the OBJ itself has no colour.