Is there a script that could do that automatically? I spent a while manually doing this layer by layer a long time ago and just got a gig that could mean thousands of layers needing to pop in like this.
Help! There isn’t enough energy drinks on earth to do this manually
although you already got an answer to this, to sequence layers I use a free script called “sequencer” from videocopilot.It’s available inside the project files archive here: http://www.videocopilot.net/tutorials/3d_ball_dispersion/
I’m not sure, maybe this can help you http://www.estrellastudios.com/services/video/after-effects-quick-tip-sequence-layers/
Since you already got many useful answers, I allow myself to post the first thing your screenshot made me think about
Good luck !