Convert OFF to OBJ
Free OFF to OBJ converter that runs in your browser. See real dimensions before you download.
How to convert OFF to OBJ
- Drop your OFF file onto the converter — it opens in your browser, nothing is uploaded.
- Check the preview and the dimensions in mm; fix units or the up axis in “Units & orientation” if the size or orientation looks wrong.
- Choose OBJ as the output and click Convert. Several files download as one ZIP.
What carries over from OFF to OBJ
| OFF | OBJ | Result | |
|---|---|---|---|
| Colour / materials | No | Yes | — |
| Textures | No | Yes | — |
| Units stored in file | No | No | Numbers in mm |
| Separate parts | No | Yes | — |
| Usual up axis | Z | Y | Rotated (switchable) |
About OFF files
OFF, the Object File Format, was defined for Geomview, an interactive geometry viewer developed at the Geometry Center at the University of Minnesota in the 1990s. A file is plain text. The first line holds the keyword OFF, the second gives the counts of vertices, faces and edges, then each vertex appears as three coordinates and each face as a vertex count followed by index numbers. Variants add colour (COFF), normals (NOFF) or texture coordinates (STOFF) through prefixes, and colour is optional at the end of each line. The simplicity made it a favourite in computational geometry, and benchmark sets such as ModelNet used it for machine-learning research on shape classification. CGAL and libigl read and write it directly. It has no units, materials or scene structure, so it is rarely a printing format, but converting it is common.
About OBJ files
OBJ comes from Wavefront Technologies' Advanced Visualizer software in the 1980s, and it has outlived the product. A file is plain text: lines starting with v define vertices, vt texture coordinates, vn normals, and f faces that reference those lists by index. Faces may be triangles, quads or larger polygons, and the g and o keywords group faces into named objects. Appearance is not in the OBJ at all; a line called mtllib points to a separate .mtl file that lists materials with diffuse colours and texture image names. The format is verbose, has no official unit and no scene hierarchy or animation, but it is trivial to read and write. That is why scanners, photogrammetry tools, sculpting programs and game pipelines still use it to move static meshes around.
3D printing notes
Few slicers open OFF directly, so the usual job is converting a research or dataset mesh into STL or 3MF. Dataset meshes such as those in ModelNet are often unit-less, normalised to a small box and not designed for printing, so they can be scaled to a size of one unit and have thin shells or holes. Set the printed size deliberately, then run a repair. MeshShift reads and writes OFF in the browser, shows real dimensions, lets you rescale, and converts to STL, 3MF, OBJ, GLB or PLY. Its print check finds holes and flipped normals and can rebuild a closed solid at the same size before you slice.
Frequently asked questions
Is this OFF to OBJ converter free and private?
Yes. The conversion runs in your browser with JavaScript and WebAssembly, so your OFF file is never uploaded to a server. There is no sign-up, no watermark and no daily limit; very large files are limited only by your device's memory.
What is an OFF file used for?
OFF is a simple mesh format used mainly in geometry processing and machine-learning research. Datasets like ModelNet ship as OFF because the format is easy to parse. It is a plain text list of vertices and faces.
Why does my OBJ import without its colours or textures?
The colour information is in a separate .mtl file and image files. If the MTL or textures are missing, renamed or in another folder, the importer shows plain grey geometry. Keep the OBJ, MTL and images together, or convert to GLB, which packs them in one file.