3D file formats
What STL, OBJ and 3MF store, what they leave out, and which tools on this site read and write them.
Side by side
| Property | STL | OBJ | 3MF |
|---|---|---|---|
| Full name | Stereolithography (also read as Standard Triangle Language) | Wavefront Object | 3D Manufacturing Format |
| Extension | .stl | .obj (+ .mtl for materials) | .3mf |
| MIME type | model/stl | model/obj | model/3mf |
| Encoding | Binary or text (ASCII) | Text | ZIP archive with XML |
| Surface | Triangles only | Polygons with any number of corners | Triangles |
| Shared vertices | No, every triangle stores its own corners | Yes | Yes |
| Colours and materials | No, not in the standard | Yes, in a separate MTL file with texture images | Yes, colours and materials in the file |
| Units | Not stored | Not stored | Yes: micron, mm, cm, inch, foot or metre |
| Several objects | No, one list of triangles | Yes, named objects and groups | Yes, with their place on the build plate |
| Opened by | Every slicer and CAD program | Modelling programs (Blender, 3ds Max, Maya), game engines and most slicers | Slicers (PrusaSlicer, Bambu Studio, OrcaSlicer, Cura) and Windows 3D Builder |
From images to STL
PNG, JPG and SVG are 2D formats, but a logo, drawing or terrain map in them can become a printable model.