Animating Morph Targets

        // Animate morph target influences
        let time = 0;
        scene.onBeforeRenderObservable.add(() => {
            time += scene.getEngine().getDeltaTime() / 1000;
            
            // Smile-frown cycle
            smileTarget.influence = Math.sin(time * 0.5) * 0.5 + 0.5;
            frownTarget.influence = Math.sin(time * 0.5 + Math.PI) * 0.5 + 0.5;
            
            // Occasional blink
            blinkTarget.influence = Math.pow(Math.sin(time * 3), 16);
        });
    }
});