Wavefront OBJ .obj
The universal plain-text mesh format. Opens almost anywhere.
What an .obj file holds
OBJ is the closest thing 3D has to a lingua franca. It is a plain-text list of vertices, texture coordinates, normals and faces, first shipped by Wavefront Technologies in the 1980s and still readable by essentially every 3D application written since. Materials live in a separate .mtl sidecar file, which is why an OBJ often arrives untextured: the .mtl and the image files got left behind. OBJ stores no animation, no rig and no scene hierarchy beyond object and group names.
Commonly seen in: Blender, Maya, Cinema 4D, 3ds Max, ZBrush, MeshLab.
| Data | Stored in OBJ |
|---|---|
| Geometry | Yes |
| Materials and colour | Yes |
| Texture maps | Yes |
| Animation and rigs | No |
| Scene hierarchy | Yes |
| Read here | Yes |
| Written here | Yes |
Tested against a real file
The last sweep loaded spider.obj from Assimp test models with its 12 sidecar files through the viewer on this site: 1,368 triangles across 19 meshes and 4 materials, in 2.4 seconds. Every format's result is on the test results page, run 2026-09-08.
What we put in an .obj file we write
Geometry and texture coordinates, with a usemtl line naming the material on each mesh. No .mtl file is written to define those names, which is a limit of three’s OBJ exporter rather than of the format, so colours and texture images do not survive the trip. Convert to GLB or FBX if the materials matter.
Files to bring with it
Drop the .mtl file and any textures in together and they will be picked up automatically.
Convert OBJ to another format
Every pairing has a page saying what survives the trip.
Convert something else to OBJ
Other things to do with an .obj file
Questions about OBJ
How do I open an .obj file?
Drop it into the viewer on this site and it opens in the browser, with the scene tree, the materials and the mesh statistics. Nothing is uploaded. If you want it in another program instead, convert it to GLB, which almost everything reads.
Is OBJ a good format to archive in?
OBJ stores geometry, materials and colour, texture maps, scene hierarchy. Anything outside that list will not be in the file at all, so archive the original alongside it if the surfacing or the rig matters.
Does converting OBJ lose quality?
Geometry is copied vertex for vertex, so the shape does not degrade. What gets lost is whatever the target format has no field for: convert to STL and the materials go, convert to OBJ and the animation goes. The comparison table on each converter page says exactly which.
Written up on the blog
Formats that hold the same things
Or go back to the full format reference.