OneTaskBy Tim King · Updated
OBJ to GLB
Convert OBJ to GLB Online With Materials, Free
OneTask is free, with no sign-up, and built by one person.
If this tool saved you time, a coffee helps keep new ones coming.
How the OBJ To GLB works
This OBJ to GLB converter packs mesh, materials and textures together. OBJ is the old universal exchange format: a text mesh, a separate .mtl material file and loose texture images. GLB packs all of that into one binary file that web viewers, AR quick-look and game engines open directly. Drop the .obj here together with its .mtl and textures, check the preview, and download a single .glb. Everything is converted in your browser.
OBJ to GLB: drop the whole set
Select or drag the .obj, the .mtl it references and every texture image at the same time. The tool reads the mtllib line in the OBJ to find the matching material file, loads the textures by the filenames the .mtl names, and builds the model with its colours and maps. If you drop the .obj alone it still converts, but with a plain grey material. A missing texture shows as a flat colour rather than stopping the conversion.
What ends up in the GLB
Every group and object in the OBJ becomes a named mesh in the GLB, so parts stay separate and keep their names. Diffuse colours, diffuse textures, opacity and the specular-to-roughness approximation from the .mtl become physically based glTF materials, and the texture images are embedded in the binary, so the one file is self-contained. Vertex normals are kept when the OBJ has them and computed when it does not, so smooth surfaces stay smooth.
Up axis and units
Most OBJ files are Y up, which is what glTF expects, so the default is to leave orientation alone. Files from CAD and some scanners are Z up and arrive lying on their side; switch the OBJ up axis menu to Z up and the tool stands them upright before export. OBJ has no unit, but glTF is defined in metres. If the model was made in millimetres, choose mm to m and it is scaled by 0.001 on export so it appears at real size in AR and engine scenes.
Checking the result
The viewport shows the model exactly as the GLB will contain it: same materials, same textures, same orientation. Use wireframe shading to look for stray faces and the stats in the rail for triangle and vertex counts. A GLB with several million triangles will load slowly on phones, so decimate heavy scans before converting.
FAQ
Do textures come through?
Yes, when they are dropped alongside the .obj and .mtl and their filenames match what the .mtl lists. PNG, JPEG, WebP and BMP work directly; TGA is read by the loader too. The images are embedded in the GLB, so there are no side files to keep together afterwards.
Why do some materials look different?
OBJ materials are an old Phong model with ambient, diffuse and specular colours. glTF uses metallic-roughness. The converter maps diffuse colour and texture straight across and estimates roughness from the specular exponent, which is close for matte and plastic surfaces but cannot reproduce coloured specular highlights.
Can I convert to .gltf instead of .glb?
This tool writes .glb, the single-file binary form, because it is the one that web viewers and engines prefer and it cannot lose its textures. Any application that reads .gltf also reads .glb, and most can re-save as the text form if you need it.
See also: all Images tools, Units, Audio & Video, Documents, Data & Code.
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