OBJ file format
The text format from Wavefront that modelling programs and game engines exchange, with materials in a separate MTL file.
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Tools for OBJ
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What is OBJ?
OBJ comes from Wavefront Technologies’ Advanced Visualizer. It is plain text: "v" lines list the corners once, and "f" lines build faces from them by number, so neighbouring faces share their corners. Faces can have more than three corners.
Colours and textures are not in the OBJ itself. An "mtllib" line names an MTL material file, "usemtl" lines assign its materials to faces, and the MTL file points to texture images. All of them have to travel together.
OBJ stores no units. Objects and groups are marked with "o" and "g" lines.
OBJ at a glance
| Property | OBJ |
|---|---|
| Full name | Wavefront Object |
| Extension | .obj (+ .mtl for materials) |
| MIME type | model/obj |
| Encoding | Text |
| Surface | Polygons with any number of corners |
| Shared vertices | Yes |
| Colours and materials | Yes, in a separate MTL file with texture images |
| Units | Not stored |
| Several objects | Yes, named objects and groups |
| Opened by | Modelling programs (Blender, 3ds Max, Maya), game engines and most slicers |