ThreeJS, Textures incorrect after exporting with GLTFExporter

Question

I wrote a simple application to merge a number of FBX (the first for the model / materials and the additionals for the animations) from Mixamo to produce a GLB / GLTF to be used in Godot, as I had enough of doing it manually via Blender, but I am facing an odd behaviour.

When I export the model using the GLTFExporter the textures are totally messed up.

This is the code for the export

const exporter = new GLTFExporter();

// Parse the input and generate the gltf output
exporter.parse(
    mainModel,
    // called when the gltf has been generated
    function(gltf) {
        // download the gltf file
        const blob = new Blob([JSON.stringify(gltf)], {type: 'text/plain'});
        const link = document.createElement('a');
        link.download = 'model.gltf';
        link.href = URL.createObjectURL(blob);
        link.click();
    },
    // called when there is an error in the generation
    function ( error ) {
        console.log( 'An error happened' );
        console.log(error);
    },
    {
        binary: false,
        animations: mainModel.animations,
        maxTextureSize: 4096,
        includeCustomExtensions: true
    }
);

This is the result (on the left the correct one meanwhile on the right the exported one)

Is it a known issue? Am I doing something incorrect?

Thanks for the help!

Answer 1

Your code is fine, but one file format rarely maps perfectly into another. There are always differences in the features they support, and how they express things. With access to the FBX file(s) in question someone could probably debug this, but without them it's hard to guess.

My recommendation would be to load one of the FBX files into https://threejs.org/editor/, then try exporting to GLB. The three.js editor uses the same FBXLoader and GLTFExporter files that your code uses. If it doesn't work there, it may be best to report an issue on the three.js GitHub repository. If it does work, then perhaps this issue has already been fixed in a more recent version of three.js.