From loose OBJ files to one GLB
An OBJ model often travels as several files: the .obj with geometry, an .mtl with materials and a folder of images. Lose one and the model turns gray, or the importer complains about a missing texture path.
GLB is the binary container of glTF 2.0 and keeps geometry and data in a single file that web viewers load directly. That is why OBJ to GLB is the usual step before publishing a model online.
Drop all the parts together
- Select the .obj, the .mtl and the texture images in one go, or drag them onto the page together.
- The converter reads them as one model and shows
name.glbwith its size. - Orbit the model and check that it looks complete.
- Open Info and read the size; it tells you whether the scale step below is needed.
- Press Download GLB.
Reading OBJ with MTL and textures is supported by the engine, but our tests cover geometry only, so look at the textures in the viewer before you publish. The files are read in the tab, and the full test run made zero requests to other domains.
Units: what an OBJ in millimeters turns into
OBJ records no unit, and the GLB receives the same raw numbers. glTF viewers read those numbers as meters. An OBJ modeled in meters therefore shows at its true size, while one drawn in millimeters appears a thousand times too large: a 20 mm part becomes 20 m.
For a millimeter model, open Edit → Size, enter 0.1 %, press Apply, then save through Other formats → GLB.
What was tested, and what is not offered
OBJ to GLB is in the automated suite: the GLB was re-opened and matched the OBJ in size, volume and triangle count. Saving with Draco compression is not offered, so the GLB is uncompressed. If you need the text form, Other formats writes glTF as one file or as .gltf + .bin in a zip.
Prepare the OBJ for the web
Scanned or sculpted OBJ files can hold hundreds of thousands of triangles. Edit → Reduce triangles shrinks the mesh to a chosen percentage, and Info lists the count so you can watch the file get lighter.
The same Edit panel rotates about X, Y or Z by any angle if the model faces the wrong way, and Undo steps back up to 20 times. Then save once more through Other formats → GLB.
Fixing a GLB made from OBJ
- Textures missing in the GLB. The images were not dropped with the .obj, or the .mtl points to another folder name. Drop all files together and convert again.
- The model is gray on purpose. An .obj without an .mtl converts fine; the GLB simply has no materials.
- Dark faces in the web viewer. Inward normals are common in hand-built OBJ files. Edit → Repair makes them consistent and outward.
- Several OBJ files for one shop. Batch conversion is not offered; Convert another file loads the next one.
Neighboring pages for OBJ and GLB
The reverse is GLB to OBJ, Draco files included. Preview the source in the OBJ viewer and the result in the GLB viewer. For a printer, OBJ to STL is the right pair; for CAD, OBJ to STEP writes a faceted body.
Questions and answers
Do I need to drop the .mtl file with the OBJ?
Only if you want materials. The geometry converts from the .obj alone, and the shape in the GLB is the same either way.
Are the textures packed into the GLB?
The engine reads OBJ textures, but texture transfer is not covered by our tests. Check the result in the GLB viewer.
Can the GLB be Draco-compressed?
No. Saving with Draco is not offered; the GLB holds uncompressed meshes.
Why is my model huge in the web viewer?
It was drawn in millimeters and glTF reads meters. Scale it to 0.1 % in Edit → Size and save again.
Can I convert a batch of OBJ files?
No, batch conversion is not offered. Convert another file loads the next one.
Can I convert the OBJ to glTF text instead?
Yes. Other formats gives one .gltf with the buffer embedded or a zip with .gltf and .bin.
How do I keep the GLB small enough for a product page?
Reduce triangles in Edit before saving and watch the count in Info. A sphere cut to 30 % of its triangles kept its volume within 2 % in our test, so a modest cut rarely changes how the shape looks on screen.