I was writing a post where I wanted to insert a 3D model to picture it better, and I even thought in doing a viewer myself. But I didn’t have to browse long to find Three.js.
It’s all invented!
Link CDN library
For this example, I'll use the official CDN libraries, instead of downloading the files to a server.
Create a basic .html file as suggested in the documentation:
https://threejs.org/docs/index.html#manual/en/introduction/Creating-a-scene
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>My first three.js app</title>
<style>
body { margin: 0; }
</style>
</head>
<body>
<script async src="https://unpkg.com/[email protected]/dist/es-module-shims.js"></script>
<script type="importmap">
{
"imports": {
"three": "https://unpkg.com/[email protected]/build/three.module.js"
}
}
</script>
<script>
//App code goes here
</script>
</body>
</html>Create a scene
Let's keep with the example and fill up the second <script> block defining a scene with an animated rotating cube:
<script type="module">
import * as THREE from 'three';
const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHeight, 0.1, 1000 );
const renderer = new THREE.WebGLRenderer();
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );
const geometry = new THREE.BoxGeometry( 1, 1, 1 );
const material = new THREE.MeshBasicMaterial( { color: 0x00ff00 } );
const cube = new THREE.Mesh( geometry, material );
scene.add( cube );
camera.position.z = 5;
function animate() {
requestAnimationFrame( animate );
cube.rotation.x += 0.01;
cube.rotation.y += 0.01;
renderer.render( scene, camera );
};
animate();
</script>All of this would look like this:
Add drag controls and background
Now we have a base to work with. We can add some functionality inserting the OrbitControls module.
//Import new modules at the beginning of the script
import { OrbitControls } from 'https://unpkg.com/[email protected]/examples/jsm/controls/OrbitControls.js';
//then add the mouse controls after declaring the camera and renderer
const controls = new OrbitControls( camera, renderer.domElement );Also, you can modify the background easily, but you will need to host your images within your app in a server, or run it locally, because of CORS. I will be using the background image of the blog header, which was taken from Stellarium.
First define a texture. Then, add it to the scene:
//do this before rendering, while defining the scene
//define texture
const texture = new THREE.TextureLoader().load( "https://theroamingworkshop.cloud/demos/Unity1-north.png" );
//add texture to scene
scene.background=texture;Full code:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>My first three.js app</title>
<style>
body { margin: 0; }
</style>
</head>
<body>
<script async src="https://unpkg.com/[email protected]/dist/es-module-shims.js"></script>
<script type="importmap">
{
"imports": {
"three": "https://unpkg.com/[email protected]/build/three.module.js"
}
}
</script>
<body style="margin: 0; width:100%;height:300px;">
<script async src="https://unpkg.com/[email protected]/dist/es-module-shims.js"></script>
<script type="importmap">
{
"imports": {
"three": "https://unpkg.com/[email protected]/build/three.module.js"
}
}
</script>
<script type="module">
import * as THREE from 'three';
import { OrbitControls } from 'https://unpkg.com/[email protected]/examples/jsm/controls/OrbitControls.js';
const scene = new THREE.Scene();
const texture = new THREE.TextureLoader().load( "https://theroamingworkshop.cloud/demos/Unity1-north.png" );
scene.background=texture;
const camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHeight, 0.1, 1000 );
const renderer = new THREE.WebGLRenderer();
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );
const controls = new OrbitControls( camera, renderer.domElement );
const geometry = new THREE.BoxGeometry( 1, 1, 1 );
const material = new THREE.MeshBasicMaterial( { color: 0x00ff00 } );
const cube = new THREE.Mesh( geometry, material );
scene.add( cube );
camera.position.z = 5;
function animate() {
requestAnimationFrame( animate );
cube.rotation.x += 0.01;
cube.rotation.y += 0.01;
renderer.render( scene, camera );
};
animate();
</script>
</body>
</html>Insert a 3D model
Now let's replace the cube for our own 3D model which, in the case of Three.js, will be a glTF (.GLB o .GLTF) format, that is most supported and renders faster (.fbx, .stl, .obj and so on are also supported).
I will export a .glb of this basic Raspberry Pi 4B case that I did some time ago using Blender:
Now, replace the <script> block based on the "webgl_loader_gltf" which was shown at the start of the post:
<script type="module">
import * as THREE from 'three';
import { GLTFLoader } from 'https://unpkg.com/[email protected]/examples/jsm/loaders/GLTFLoader.js';
import { OrbitControls } from 'https://unpkg.com/[email protected]/examples/jsm/controls/OrbitControls.js';
let camera, scene, renderer;
init();
render();
function init() {
const container = document.createElement( 'div' );
document.body.appendChild( container );
camera = new THREE.PerspectiveCamera( 30, window.innerWidth / window.innerHeight, 0.1, 20 );
camera.position.set( 0.2, 0.2, 0.2 );
scene = new THREE.Scene();
scene.add( new THREE.AmbientLight( 0xffffff, 0.75 ) );
const dirLight = new THREE.DirectionalLight( 0xffffff, 1 );
dirLight.position.set( 5, 10, 7.5 );
dirLight.castShadow = true;
dirLight.shadow.camera.right = 2;
dirLight.shadow.camera.left = - 2;
dirLight.shadow.camera.top = 2;
dirLight.shadow.camera.bottom = - 2;
dirLight.shadow.mapSize.width = 1024;
dirLight.shadow.mapSize.height = 1024;
scene.add( dirLight );
//model
const loader = new GLTFLoader();
loader.load( 'https://theroamingworkshop.cloud/threeJS/models/rPi4case/rPi4_case_v1.glb', function ( gltf ) {
scene.add( gltf.scene );
render();
} );
renderer = new THREE.WebGLRenderer( { antialias: true } );
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
renderer.toneMapping = THREE.ACESFilmicToneMapping;
renderer.toneMappingExposure = 1;
renderer.outputEncoding = THREE.sRGBEncoding;
container.appendChild( renderer.domElement );
const controls = new OrbitControls( camera, renderer.domElement );
controls.addEventListener( 'change', render );
controls.minDistance = 0.001;
controls.maxDistance = 1;
controls.target.set( 0.03, 0.01, -0.01 );
controls.update();
window.addEventListener( 'resize', onWindowResize );
}
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
render();
}
function render() {
renderer.render( scene, camera );
}
</script>Basically it does the following:
- Import used modules:
- GLTFLoader will load our model in .glb format
- OrbitControls for camera rotation and position
- Define the scene:
- define a camera
- define the light (in this case, ambient and directional; try commenting each of them to see the difference)
- define a background
- Load the model in the scene
- Define rendering parameter and render.
All of it finally looks like this (click and drag!):
Hope it's useful! Doubts or comments on 🐦 Twitter!
