For developers prioritizing web-based AR, AR.js is the superior choice. Its prowess in marker-tracking, geo-location and 3D model integration, along with compatibility with ARKit and ARCore, make it a robust, mobile-agnostic AR solution. Use Three.js if your primary focus is sophisticated 3D graphics rendering and a broad contributor base for support.

AR.js and Three.js compared

Key Differences Between AR.js and Three.js

  • AR.js is fine-tuned for creating augmented reality web apps, whereas Three.js is a JavaScript library for 3D graphics.
  • AR.js supports both marker-based and marker-less AR; Three.js excels in 3D animations using WebGL.
  • AR.js is compatible with ARKit and ARCore, making it amenable to use on iOS and Android devices, while Three.js delivers broad browser compatibility.
  • Both libraries are open-source; however, Three.js boasts a more significant contributor base on GitHub.
ComparisonAR.jsThree.js
FoundationWebAR standardWebGL
Model Integration3D models3D computer graphics
Interactive Features/AnimationsYesYes
AR TypeMarker-based and Location-basedSupports AR via WebXR
Development LanguageJavaScriptJavaScript
CompatibilityCompatible with iOS and AndroidAll browsers that support WebGL 1.0
Creation ProcessAllows Web AR experiences creation on-the-flyCreate complex 3D animations easier
Coding ApproachHTML+CSS and Vanilla JavaScriptJavaScript, GLSL
Key FeaturesVarious marker types, geolocation, lightning and shading for virtual objectsMultiple effects, scenes, cameras, animations, lights, materials, shaders, objects, geometry, support options
UsageMarker-based and marker-less AR applications3D modeling and animation

What Is AR.js and Who’s It For?

An incredibly accessible library for AR web app creation, AR.js leverages marker images akin to QR codes for the display of 3D models. Suited for developers and tech enthusiasts, it delivers remarkable freedom for 3D model customization, enabling the tailoring of pre-made models or creation of new ones. Base functionality rooted in the WebAR standard lends AR.js its prowess in marker-based AR. Whether you work on iOS or Android devices, you’ll find compatibility with ARKit and ARCore.

Colorful interactions of a developer with a computer in a high-tech lab

Pros of AR.js

  • AR experiences facilitated for web applications
  • Supports various types of AR including image tracking and location-based
  • Compatible with both iOS and Android devices through ARKit and ARCore

Cons of AR.js

  • Requires inclusion of specific libraries for implementation
  • Although initial implementation is uncomplicated, local code testing or deployment is necessary for the final step

What Is Three.js and Who’s It For?

Witness the result of collective creativity and expertise: Three.js. Unveiled in 2010 by Ricardo Cabello, this JavaScript library is instrumental in the creation and display of animated 3D computer graphics within a web browser. Ideally made for developers and graphics enthusiasts, it simplifies complex 3D animations without the necessity for browser plugins. It also supports Virtual Reality and Augmented Reality via WebXR, bridging the gap between creativity and technology.

Colorful animated 3D graphic being manipulated by a developer in an office

Pros of Three.js

  • 3D animations can be created and displayed without any browser plugins
  • Supports multiple scenes, effects, graphics, animations, materials, and more
  • Extensive WebXR support for Virtual and Augmented Reality

Cons of Three.js

  • Requires knowledge of JavaScript and GLSL
  • Although first created in 2010, it doesn’t support all now-standard 3D rendering features

Code Examples for AR.js & Three.js

AR.js: Animate a 3D Model

Here is an example of how to animate a 3D model using AR.js. This snippet rotates a model in place upon activation. For this script to function optimally, ensure that the AR.js and A-Frame libraries are loaded and an appropriate 3D model is linked.

<a-scene embedded arjs>
  <a-marker preset="hiro">
    <a-entity gltf-model="#animated-asset" animation-mixer="clip: run"></a-entity>
  </a-marker>
  <a-entity camera></a-entity> 
</a-scene>

Three.js: Interactive Sphere Geometry

This example demonstrates how to create an interactive sphere geometry with Three.js. Users can control its rotation via mouse input. This piece of code requires Three.js library to be loaded and a setup for WebGL renderer, scene, and mouse controllers.

let sphere;
let mouseX = 0, mouseY = 0;

// Sphere geometry
const geometry = new THREE.SphereGeometry(50, 20, 20);

// Material
const material = new THREE.MeshBasicMaterial({ color: 0x00ff00, wireframe: true });

// Sphere
sphere = new THREE.Mesh(geometry, material);
scene.add(sphere);

// Mouse move event
document.addEventListener('mousemove', onMouseMove, false);

// Function to rotate sphere based on mouse position
function onMouseMove(event) {
    mouseX = event.clientX - windowHalfX;
    mouseY = event.clientY - windowHalfY;
    sphere.rotation.x += (mouseY - sphere.rotation.x) * 0.05;
    sphere.rotation.y += (mouseX - sphere.rotation.y) * 0.05;
}

Final Decision: AR.js or Three.js? Ask thyself.

In the clash between tech titans AR.js and Three.js, the victor finds form in the substance of your needs. Let’s dissect.

Web AR Enthusiasts

AR.js might just be your grail. With its robust augmented reality capabilities, it offers ample flexibility. Its arsenal includes image tracking, location-based AR, variety of markers, interactive features, animation and 3D customisations. You can craft AR experiences on the fly with automatic code generation and compatibility with iOS and Android devices. Choose AR.js if web AR applications, both marker-based and marker-less, are your forte.

Web AR developer brainstorming AR applications

Casual 3D Programmers

If you are a casual 3D programmer who needn’t grapple with complex augmented reality functionalities, Three.js makes more sense. Provides GPU-accelerated 3D animations sans browser plugins. Simple creation and display of animated 3D graphics in a web browser? Three.js is your game.

Casual programmer exploring 3D animations

Pro 3D Animators

Should complexity be your muse, Three.js asserts itself. It facilitates advanced 3D animations and effects. Libraries make heavy graphics easier to manage. Dedicated contributors on GitHub ensure a well-maintained environment, if support from an active community tops your priorities.

Professional 3D animator deeply engrossed in complex graphics creation

AR.js or Three.js? The dichotomy boils down to user requirements. For robust AR capabilities, AR.js reigns. Three.js outshines its counterpart in simplified 3D programs. Yet, for complex 3D animations, it holds its own.