OBJ ↔ GLB / glTF Converter

OBJ is a 1992 text-based format from Wavefront, designed for 3D modeling and animation. It stores geometry, normals, UVs, and references materials through a separate .mtl file. GLB is the binary form of glTF 2.0, designed in 2017 specifically for modern web and real-time applications. It’s compact, self-contained, and the de facto standard for web-based 3D. OBJ stays popular because of its simplicity and universal support in modeling software.

If you upload only the .obj file (no accompanying .mtl), the output GLB will have a generic gray material applied. This converter currently handles single-file OBJ uploads. To preserve materials and textures, do the conversion in Blender or another full 3D editor where you can load both files together.

Yes. The exported GLB conforms to glTF 2.0 and works in <model-viewer>, three.js, Babylon.js, Sketchfab, Unity, Unreal, Blender, and any other tool that accepts glTF. For Sketchfab specifically, GLB is the preferred upload format.

The geometry is preserved exactly — every vertex and triangle from the GLB appears in the OBJ. PBR materials from the GLB are not transferred (OBJ’s .mtl format doesn’t support PBR), but vertex normals and UV coordinates carry over. If the GLB contains multiple meshes, they’re written as named groups in the OBJ.

Different 3D software uses different conventions for which axis is “up”. Web 3D formats (GLB, glTF) and three.js use Y-up. CAD and BIM tools like Revit, AutoCAD, FreeCAD, and SolidWorks use Z-up. OBJ files exported from these tools carry Z-up coordinates, which appear rotated when loaded into a Y-up viewer. Use the “Source up axis” toggle in the file info panel to switch — your model will display upright in the preview, and the exported file will be saved in standard Y-up orientation.

For Android and WebXR — yes, GLB works directly. For iOS AR Quick Look you need USDZ, which Apple’s free Reality Converter can generate from a GLB file in seconds. So the typical workflow is: OBJ → GLB (here) → USDZ (in Reality Converter, if you need iOS support).

Pick GLB unless you have a specific reason not to. It’s a single self-contained file, smaller, and accepted by all modern 3D viewers and engines. Choose glTF only if you need a human-readable JSON file — for debugging, scripting, or pipelines that expect text-based formats.

Buildref has a growing set of free in-browser 3D converters. For bidirectional STL and OBJ conversion, use our STL ↔ OBJ converter. For STL to web-ready 3D formats, see the STL to GLB converter. To inspect a 3D model without converting it, try the free online 3D viewer. The full list is on the converters hub page.

Yes. The conversion is lossless — every triangle from the input appears in the output with the exact same vertex positions. Vertex normals and UV coordinates are preserved when present. No simplification, no smoothing, no decimation.