GLB animation: Creating and implementing animated 3D models for games

Have you ever struggled with implementing animations in your 3D models for web or mobile games? GLB files have become the go-to format for delivering animated 3D content across platforms, but working with them effectively requires understanding their capabilities and limitations. This guide will walk you through everything you need to know about creating, exporting, and playing GLB animations.

What is GLB animation?

GLB (binary glTF) is a file format that efficiently packages 3D models and their animations into a single binary file. Unlike other formats, GLB excels at:

• Compact file sizes: The binary format reduces file size while maintaining visual quality
• Cross-platform compatibility: Works across web, mobile, and desktop environments
• Animation support: Handles both skeletal animations and morph targets
• Web-friendly delivery: Optimized for three.js and WebGL applications

Yes, GLB fully supports animations! The format can store keyframe data for skeletal animations (rigged models) and morph targets (shape keys), making it ideal for game characters, interactive objects, and environmental effects. However, it’s worth noting that GLB does have some limitations with complex animation techniques like inverse kinematics or physics-based simulations, which might require preprocessing in your 3D software.

Creating GLB animations in Blender

Blender is one of the most popular tools for creating and exporting GLB animations. Here’s a streamlined workflow:

1. Model preparation

Before animating, ensure your model is properly prepared:

• Create clean topology with appropriate polygon count
• Apply proper UV unwrapping for textures
• Set up armatures and skinning weights for character models

If you’re starting with an AI-generated model from tools like Alpha3D’s model generator, you may need to refine the topology before rigging and animation. AI models often require additional work in Blender to ensure proper UV mapping and vertex weighting before they’re ready for animation.

2. Animation creation

Create your animations using Blender’s animation tools:

• Use the Timeline and Dope Sheet to set keyframes
• For character animations, utilize the Action Editor to organize multiple animation clips
• Consider using the NLA Editor for complex animation sequences

Think of the NLA Editor as a sophisticated mixing board for your animations. It allows you to layer, blend, and organize multiple animation sequences - perfect for creating complex character behaviors from simpler animation building blocks.

3. Export settings

When your animations are ready, export using these settings:

1. Go to File > Export > glTF 2.0
2. Select glTF Binary (.glb) format
3. Under Animation tab, ensure Include Animations is checked
4. Enable Skinning and Shape Keys if your model uses them
5. Set appropriate sampling rate (higher for complex animations, lower for simple ones)

Pro tip: Test your animations before final export by playing them in Blender’s viewport to catch any issues with rigging or keyframes. This simple check can save hours of debugging later when your animation doesn’t play correctly in your game engine.

Implementing GLB animations with three.js

Three.js is the most common library for displaying GLB animations on the web. Here’s how to implement them:

Loading the model

// Import required modules
import * as THREE from 'three';
import { GLTFLoader } from 'three/examples/jsm/loaders/GLTFLoader.js';

// Set up scene, camera, renderer (basic three.js setup)
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);

// Load the GLB model
const loader = new GLTFLoader();
let mixer;

loader.load('model.glb', function(gltf) {
  scene.add(gltf.scene);

  // Set up animation mixer if animations exist
  if (gltf.animations && gltf.animations.length) {
    mixer = new THREE.AnimationMixer(gltf.scene);
    const action = mixer.clipAction(gltf.animations[0]);
    action.play();
  }
});

Playing and controlling animations

To control animations, you’ll need to:

1. Create an animation mixer for your model
2. Access the animation clips from the loaded GLB
3. Create actions from these clips
4. Play, pause, or blend between animations

// Animation clock for updating
const clock = new THREE.Clock();

// Animation loop
function animate() {
  requestAnimationFrame(animate);

  // Update animations
  if (mixer) {
    mixer.update(clock.getDelta());
  }

  renderer.render(scene, camera);
}
animate();

For more advanced control, you can:

// Play a specific animation by name
function playAnimation(name) {
  const clip = THREE.AnimationClip.findByName(gltf.animations, name);
  if (clip) {
    const action = mixer.clipAction(clip);
    action.reset().fadeIn(0.5).play();
  }
}

// Crossfade between animations
function crossfadeTo(newActionName, duration = 0.5) {
  const newClip = THREE.AnimationClip.findByName(gltf.animations, newActionName);
  if (newClip) {
    const newAction = mixer.clipAction(newClip);
    currentAction.crossFadeTo(newAction, duration, true);
    currentAction = newAction;
  }
}

The crossfade functionality is particularly useful for creating smooth transitions between animations, such as a character changing from walking to running based on player input.

Common issues and troubleshooting

When working with GLB animations, you might encounter these common issues:

Issue	Solution
Missing animations	Verify “Include Animations” was checked during export
Animation glitches	Check rigging and weight painting in Blender
Performance issues	Optimize model complexity and reduce keyframe density
Texture problems	Ensure UV maps are correctly applied and textures are included
Broken animation sequences	Bake animations to keyframes in Blender before export

For complex animations that aren’t working properly, you might need to bake them to simpler keyframes in Blender before export. This is especially true for animations that rely on inverse kinematics or physics simulations, which GLB doesn’t fully support.

GLB vs. glTF: Which to choose?

GLB and glTF are closely related formats, but they have key differences:

• GLB: Single binary file, smaller size, faster loading, ideal for web deployment
• glTF: Multiple files (JSON + external resources), easier to edit, better for development

For game development, GLB is generally preferred due to its compact size and ease of distribution. According to a comparison of 3D file formats, GLB has become one of the most common 3D model file formats due to its efficiency and wide support.

Consider this practical example: A character model with textures and animations might be 15MB as separate glTF files but only 8MB when packaged as a GLB file. For web games where every kilobyte matters, this difference can significantly impact loading times and player experience.

However, during development, you might work with glTF files and convert to GLB for final deployment. This approach gives you the flexibility to easily modify individual components during development while benefiting from GLB’s efficiency in production.

Optimizing GLB animations for games

Performance is critical for game development. Here are some optimization tips:

1. Reduce polygon count: Use the lowest poly count that maintains visual quality
2. Optimize texture sizes: Compress textures and use appropriate resolutions
3. Simplify animations: Remove unnecessary keyframes and reduce animation complexity
4. Use Level of Detail (LOD): Implement different detail levels based on camera distance
5. Consider animation compression: Tools like glTF-Transform can optimize animation data

For mobile games, these optimizations are especially important, as they can significantly impact frame rates and battery life. A well-optimized GLB model might run at 60fps while a poorly optimized one struggles at 15fps on the same device.

When working with 3D modeling services, be sure to specify performance requirements upfront. The cost of 3D modeling might increase slightly for optimization work, but the performance benefits are well worth it.

Advanced techniques

Once you’ve mastered the basics, consider these advanced techniques:

Procedural animation blending

Combine pre-baked animations with procedural modifications for dynamic movement:

// Blend between walking and running based on speed
function updateLocomotion(speed) {
  const walkAction = mixer.clipAction(walkAnimation);
  const runAction = mixer.clipAction(runAnimation);

  // Normalize speed between 0-1
  const blendFactor = Math.min(speed / maxSpeed, 1);

  walkAction.setEffectiveWeight(1 - blendFactor);
  runAction.setEffectiveWeight(blendFactor);

  walkAction.play();
  runAction.play();
}

This technique allows your character to smoothly transition between animations based on gameplay parameters, creating more natural movement than simply switching between discrete animation states.

Retargeting animations

You can reuse animations across different character models using retargeting. While this is typically done in Blender before export, you can also implement it programmatically:

// Simplified example of retargeting bone positions
function retargetAnimation(sourceAnimation, targetSkeleton) {
  // Clone the animation
  const retargetedClip = sourceAnimation.clone();

  // Map source bones to target bones
  // Adjust track data to match target skeleton proportions

  return retargetedClip;
}

Animation retargeting is invaluable for game studios working with multiple character models. Rather than animating each character individually, you can create one set of high-quality animations and retarget them to different character rigs, saving significant time and resources.

Future of GLB animations

The landscape of 3D modeling and animation is rapidly evolving, particularly with the rise of AI tools. As discussed in this article about AI’s impact on 3D modeling, AI is already transforming workflows by automating repetitive tasks and generating variations.

For GLB animations specifically, we can expect:

1. AI-assisted animation generation: Tools that can automatically create basic animations from text prompts
2. Better compression and optimization techniques: Reducing file sizes while maintaining visual quality
3. Enhanced real-time capabilities: Improved support for physics and dynamic animations
4. Improved integration with game engines: Seamless workflows between modeling, animation, and implementation

AI retopology tools are already helping optimize models for animation by automatically generating clean topology with proper edge flows. This technology streamlines the preparation of models for animation, reducing hours of manual work to minutes of supervised AI processing.

Conclusion

GLB animations offer a powerful, efficient way to incorporate animated 3D content into your games and applications. By understanding the workflow from creation in Blender to implementation in three.js, you can create engaging, interactive experiences that perform well across platforms.

The format’s balance of file size efficiency and animation capability makes it ideal for web and mobile games where performance is critical. And as 3D modeling tools evolve, creating and implementing GLB animations will only become more accessible and powerful.

Ready to bring your game characters to life? Start by making 3D models from photos with AI assistance, then apply the animation techniques from this guide to create engaging, interactive experiences that captivate your players.