Gltf Animation loops when i click, how to stop the loop

Hallo everyone,
i made a Gltf Model with a Animation. What I want is: the animation doesn’t play at first. The animation starts playing once when I click on the model. Then I click on the model again and the animation plays backwards once. Click again to play the animation normally once. and so on. I made it BUT, when the animation is not finished, I click on the model and the animation loops automatically. I dont want it to loop. How to fix it?

I created a test model. This is my code:

var createScene = function() {
var scene = new BABYLON.Scene(engine);

var camera = new BABYLON.FreeCamera("camera1", new BABYLON.Vector3(0, 5, -10), scene);


camera.attachControl(canvas, true);
    function (newMeshes) {          
        scene.createDefaultCameraOrLight(true, true, true);
        var animation = scene.animationGroups[0];
        animation.speedRatio = 0;
        animation.loopAnimation = false;
        var isForward = true; // 
        var isPlaying = false; // 
        var isEnd = false; // 
        var actionManager = new BABYLON.ActionManager(scene);
        newMeshes.forEach(function(mesh) {
            if (mesh.getTotalVertices() > 0) {
                mesh.actionManager = actionManager;
                    new BABYLON.ExecuteCodeAction(
                        function() {
                            // play animation
                            if (!isPlaying) {
                                isPlaying = true;
                                isEnd = true;
                                console.log("isPlaying: "+isPlaying);
                                animation.speedRatio = 1; // set the speed
                            } else {
                                // reverse
                                if (isEnd) {
                                    isForward = !isForward;
                                    animation.speedRatio = isForward ? 1 : -1; // switch
                                } else {
                                    // stop
                                    isPlaying = false;
                                    isEnd = false;
return scene;


Looks like a bug to me, let me fix it ASAP.


It looks like we are not supporting dynamically changing the speedratio from positive to negative. You can only do it if stopping the animation.

@Evgeni_Popov can you confirm ?

1 Like

Thanks for your answers. Is it possible to disable mouse clicks while the animation is running?

I found a way to make it work:

Just stopping the animation and setting the speed ratio was not working (at least for me), the animation was restarting from frame 0 and not from the current frame. I needed to get the current frame and play the animation from this frame to the from or to frame value, depending on the direction of the animation.

@Cie You can check animation.isStarted to know if the animation is still playing or not to disable mouse clicks.


Thank you very much!

This PR will make your first PG work, without the start/stop workaround: