Ì have a CAAnimationGroup with multiple CAKeyframeAnimation for animating the bones of a skeleton. The animation is playing properly when not setting `usesSceneTimeBase`. I can pause/unpause the animation by setting `isPaused` on the scene. However, I want to control the animation with a UISlider and according to the documentation I need to set `usesSceneTimeBase` to `true`. But then the animation does not play al all, even if `isPlaying` of the SCNView is set to `true`. Also, `sceneTime` remains at 0.0.
How can I control the animation progress with a UISlider?
