OBJ to GLB converter: keeps MTL materials and textures

In short: drop an OBJ together with its .mtl file and texture images above, and click Convert to GLB. You get one GLB file with the model, its materials and its textures inside, ready for websites, three.js, Babylon.js, Godot, Unity's glTF importers and AR viewers. It runs in your browser.

#How to convert OBJ to GLB

1. Add the OBJ, its .mtl and its textures together. Select them all in the file picker, or drag them in at once. The OBJ names its .mtl file, and the .mtl names the textures, so the tool matches them by file name.
2. Check the scale. glTF is in metres. Blender's OBJ files already are; if yours was made in centimetres or millimetres, choose that so the GLB is the right size.
3. Click Convert to GLB, check the preview, and Download.

No files to hand? Try it with an example converts a textured wooden crate with a painted lid.

#What happens to the materials

OBJ materials (in the .mtl file) are described with an older lighting model: diffuse colour, specular colour and shininess. glTF uses physically based materials: base colour, roughness and metalness. The tool converts:

In the MTL	In the GLB
Diffuse colour (Kd) and texture (map_Kd)	Base colour and base colour texture
Normal map (norm)	Normal map
Bump map (map_Bump, bump)	Not kept: glTF has no bump maps
Transparency (d, Tr)	Opacity
Shininess (Ns)	Approximated as roughness
Specular colour (Ks)	Not kept: glTF's standard material has no separate specular colour
Emission (Ke, map_Ke)	Emissive colour and texture

So colours and textures come across exactly, but shiny materials can look a little different. Check the preview.

#Limits to know

• Missing files: if a texture or the .mtl isn't added, the tool says which, and leaves it out. Without the .mtl the model is plain grey.
• TGA, DDS and other texture formats that browsers can't open aren't packed. Convert them to PNG or JPEG first and update the .mtl.
• OBJ has no animation, so neither does the GLB.

#Example

The example crate, with its wood texture and blue painted lid, as one GLB:

The example crate as a GLB

#Frequently asked questions

#Are my files uploaded?

No. The OBJ, MTL and textures are read in your browser and the GLB is written there too.

#Why is my GLB grey?

The .mtl file (or the textures) wasn't added with the OBJ. Add all of them at once and convert again.

#Why is it 100 times too big?

The OBJ is in centimetres. Convert again with Centimetres to metres.

#Can I convert GLB back to OBJ?

Yes, with the GLB to OBJ converter, which writes the OBJ, MTL and textures as a ZIP.

#Does it reduce the file size?

Usually: GLB is binary, so geometry takes less space than OBJ's text, and textures are stored as they are.