three.js -如何设置自定义颜色的*.obj模型时，它交付没有*.mtl文件？

var loader = new THREE.OBJLoader();
loader.load('model.obj', function (object) {
    scene.add(object);
});

var material = new THREE.MeshBasicMaterial({ color: 0xff0000 });
object.traverse(function (child) {
    if (child instanceof THREE.Mesh) {
        child.material = material;
    }
});

var renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);

function animate() {
    requestAnimationFrame(animate);
    renderer.render(scene, camera);
}
animate();