如何在three.js中创建指向多个方向的随机对象

var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
var renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);

var geometry = new THREE.BoxGeometry(1, 1, 1);
var material = new THREE.MeshBasicMaterial({ color: 0x00ff00 });
var cube = new THREE.Mesh(geometry, material);
cube.position.set(Math.random() * 10 - 5, Math.random() * 10 - 5, Math.random() * 10 - 5);
cube.rotation.set(Math.random() * Math.PI, Math.random() * Math.PI, Math.random() * Math.PI);
scene.add(cube);

var direction = new THREE.Vector3(Math.random() * 2 - 1, Math.random() * 2 - 1, Math.random() * 2 - 1);
direction.normalize();
var origin = new THREE.Vector3(0, 0, 0);
var length = Math.random() * 5 + 1;
var color = Math.random() * 0xffffff;
var arrowHelper = new THREE.ArrowHelper(direction, origin, length, color);
scene.add(arrowHelper);

function animate() {
    requestAnimationFrame(animate);
    cube.rotation.x += 0.01;
    cube.rotation.y += 0.01;
    renderer.render(scene, camera);
}
animate();