How to set current time in Animation with ThreeJS

In ThreeJS, controlling the current time of an animation typically involves utilizing the animation system, particularly the AnimationMixer object. AnimationMixer is an object that manages animation playback, enabling you to play, pause, stop, and set the animation to a specific time point.

Assuming you have a loaded model with animations, here are the steps to set the current time using AnimationMixer:

Step 1: Create an AnimationMixer Object

First, create an AnimationMixer object for your model. This object provides the necessary API to control animation playback.

javascript
const mixer = new THREE.AnimationMixer(model);

Step 2: Get the Animation Clip

Animation data is typically stored in the model's animations property, which is an array containing multiple animation clips (AnimationClip). Select the animation clip you wish to control.

javascript
const clip = model.animations[0]; // Select the first animation clip

Step 3: Create an AnimationAction Associated with the Clip

Use the AnimationMixer.clipAction method to create an AnimationAction object that controls a specific animation clip.

javascript
const action = mixer.clipAction(clip);
action.play(); // Start playing the animation

Step 4: Set the Current Time of the Animation

Control the animation to jump to a specific time point by setting the time property of the AnimationAction. For example, to jump to the 2-second mark of the animation:

javascript
action.time = 2.0; // Time is in seconds

Step 5: Update the AnimationMixer

In the animation system, AnimationMixer must be updated every frame. This is typically done within your animation or rendering loop.

javascript
mixer.update(deltaTime); // deltaTime is the time interval between frames

Example

Assume you have a scene with an animated model. When a user clicks a button, set the animation to the 3-second mark and continue playing:

javascript
button.addEventListener('click', () => {
    action.time = 3.0; // Set the animation to the 3-second mark
    action.play(); // Ensure the animation is playing
});

In practical applications, this functionality for controlling animation time is highly valuable, such as in interactive demonstrations or games where users can navigate to specific animation segments. This enhances application interactivity and user experience.