I have copied code from https://threejs.org/examples/#webgl_loader_gltf and pasted it into an html document. I relinked all of the models, textures and .js files locally from MrDoob's JavaScript 3D library https://github.com/mrdoob/three.js/. When I link GLTF files from his folder locally on my computer I am able to view them in firefox but when I simply change the GLTF to my model I am unable to see it. I tried scalling the model down in blender before I export it and I also tried viewing it in Babylon viewer online (I was able to view my own GLTF model on the online Babylon viewer no problem).
    // model
    var loader = new THREE.GLTFLoader();
    loader.load( '../../skull_downloadable/scene.gltf', function ( gltf ) {
    gltf.scene.traverse( function ( child ) {
      if ( child.isMesh ) {
       child.material.envMap = envMap;
      }
     } );
     scene.add( gltf.scene );
    }, undefined, function ( error ) {
     console.error( error );
    } );
    renderer = new THREE.WebGLRenderer( { antialias: true } );
    renderer.setPixelRatio( window.devicePixelRatio );
    renderer.setSize( window.innerWidth, window.innerHeight );
    renderer.gammaOutput = true;
    container.appendChild( renderer.domElement );
    window.addEventListener( 'resize', onWindowResize, false );
    // stats
    stats = new Stats();
    container.appendChild( stats.dom );
   }
   function onWindowResize() {
    camera.aspect = window.innerWidth / window.innerHeight;
    camera.updateProjectionMatrix();
    renderer.setSize( window.innerWidth, window.innerHeight );
   }
 
    