@MarkHunte wrote:
You could look at putting hidden multiple waypoint on the scene. Which may be the easiest. But you may lose control if the window height changes.
Or you could look at getting the div, body etc (selector) scrollTop property. This tells you where the selector's top is when scrolling
Then you would need to calculate that pixel number against your ( timeline length time and the pixel length of the scene) which you first need to probably calculate how many pixels in length to time line seconds.