What it stores
- Vertices, faces and n-gons
- UV coordinates and normals
- Material names via a separate MTL file
- Several objects and groups
3D FILE FORMAT
OBJ: geometry plus optional materials
Wavefront OBJ stores vertices, faces, UVs and normals in a text file, with materials in a separate MTL file. It is the common exchange format between 3D software.
At a glance
What it does not store
- Units
- Scene hierarchy and animation
- PBR materials: MTL is basic
- Textures: they stay in separate image files
When to use it
- Moving a mesh between Blender, Maya or ZBrush
- Rendering with an MTL material
- Editing geometry
Limits to know
- The MTL and textures must travel with the OBJ
- Text format: larger than binary GLB
- No unit metadata
Convert to and from
OBJ → STLConvert OBJ to STLOBJ → GLBConvert OBJ to GLBOBJ → 3MFConvert OBJ to 3MF3MF → OBJConvert 3MF to OBJSTL → OBJConvert STL to OBJGLB → OBJConvert GLB to OBJPLY → OBJConvert PLY to OBJ
Questions about the format
Does OBJ include materials?+
Not inside the file. Materials live in a companion .mtl file, and textures in separate images.
Can I 3D print an OBJ?+
Yes, but STL is safer: many slicers read it directly and ignore OBJ materials.
Does OBJ keep vertex colours?+
Some tools write them, but support varies. Use GLB for reliable colours.