three.js 导入多个stl

文件并显示在场景中的示例代码：

var scene = new THREE.Scene();

var loader = new THREE.STLLoader();
var materials = [
  new THREE.MeshPhongMaterial({ color: 0xff5533, specular: 0x111111, shininess: 200 }),
  new THREE.MeshPhongMaterial({ color: 0x00ffff, specular: 0x111111, shininess: 200 }),
  new THREE.MeshPhongMaterial({ color: 0x00ff00, specular: 0x111111, shininess: 200 }),
];

var models = [
  { file: 'model1.stl', position: new THREE.Vector3(0, 0, 0), scale: 1.0, material: materials[0] },
  { file: 'model2.stl', position: new THREE.Vector3(50, 0, 0), scale: 0.5, material: materials[1] },
  { file: 'model3.stl', position: new THREE.Vector3(-50, 0, 0), scale: 2.0, material: materials[2] },
];

var count = models.length;
models.forEach(function(model) {
  loader.load(model.file, function(geometry) {
    var mesh = new THREE.Mesh(geometry, model.material);
    mesh.position.copy(model.position);
    mesh.scale.set(model.scale, model.scale, model.scale);
    scene.add(mesh);
    count--;
    if (count === 0) {
      render();
    }
  });
});

var camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);
camera.position.set(0, 0, 100);

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

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

这段代码使用了 `THREE.STLLoader` 加载多个 STL 文件，并使用不同的材质和位置、缩放参数来显示这些模型。注意在所有模型都加载完成后才调用 `render()` 函数进行渲染。