Free online OFF to OBJ converter

Meshes from research datasets and geometry-processing software are often supplied as .off files, while applications such as Blender, Maya, game asset pipelines, and older 3D tools commonly accept OBJ. Converting to .obj provides a broadly supported polygon-mesh file for editing, exchange, and import.

What the OFF format is

OFF, short for Object File Format, is a polygon-mesh format associated with the Geometry Center and widely used in computational geometry, academic datasets, mesh processing, and scanning workflows. Most OFF files are ASCII text and begin with OFF, followed by counts for vertices, faces, and edges, vertex coordinates, and face index lists.

Standard OFF describes mesh geometry and topology but normally has no material library, texture-image reference, scene hierarchy, rig, animation, or camera data. Extensions include COFF for color data and NOFF for normal data; application support for these variants is inconsistent.

What the OBJ format is

Wavefront OBJ is a text-based mesh format supported by many 3D editors, renderers, CAD utilities, game tools, and 3D-printing applications. An OBJ file can store vertex positions, polygon faces, texture coordinates, normals, object or group names, and references to materials.

Materials are normally stored in a separate .mtl file, which may reference external texture images. OBJ is useful for compatibility, but it does not standardize animation, skeletal rigs, scene structure, cameras, or embedded textures. Keep the .obj, .mtl, and texture files in the same folder when a material export is present.

Convert the mesh

To convert without installing software, upload the .off file to the converter on 101convert.com, choose OBJ as the output format, run the conversion, and download the resulting .obj file. Open the result in the destination application before deleting or replacing the source file.

MeshLab is a suitable desktop option when the mesh needs inspection or repair before export:

1. Choose File → Import Mesh and open the .off file.
2. Inspect the model for missing faces, reversed face orientation, incorrect scale, and non-manifold areas.
3. If faces are oriented inconsistently, use Filters → Normals, Curvatures and Orientation → Re-Orient all faces coherently, then verify the result visually.
4. Choose File → Export Mesh As..., select Wavefront OBJ (*.obj), and save the file.
5. Export normals when the receiving application needs smooth shading. Export texture coordinates only if the source mesh contains valid UV coordinates.

Compatibility and quality limits

Vertex positions and face connectivity normally transfer directly, but the receiving software may handle triangles and quads more reliably than arbitrary polygons. Triangulate the mesh before export if the target program rejects n-gons or displays damaged faces.

Conversion cannot create source data that OFF did not contain. Most OFF meshes have no UV mapping, materials, or texture references, so the OBJ output will usually be an untextured mesh. Color information in COFF files may be lost because OBJ has no universally supported vertex-color convention.

OBJ has no fixed unit system. If the imported model is too large or small, apply the required scale in MeshLab or the target application and document the intended units separately. If lighting or shading is wrong, recalculate or export normals and check face orientation; an OBJ can preserve incorrect normals and inverted faces from the original mesh.