Make expression controls inside composition accessible to the layer instance outside
I have a composition of a keyboard with each key to light up on a note. I make the keyboard and several checkbox controls for the highlight. Now I put the keyboard composition as a layer in a composition that has all the note info.
Why can't I make the checkboxes inside the composition available to the layer so that I can have multiple note arrangements using the same keyboard composition? I can't make this link without hard-coding the composition name into the keyboard composition. So I have to make a duplicate keyboard for each composition I want to use it in.
It would be nice and efficient if I could toggle a button on these so when I drag keyboard comp into a new composition, it has the controls inside available on the layer instance.
As Steve already pointed on, adding properties ( including expression controls ) to the Essential Graphics panel also makes them available as Master Properties on instances of that composition as a pre-comp. You can also then "push" new values into the original comp ( and all unmodified instances ) with the Push button next to the Master Properties, or "pull" the original value if you've changed it with the Pull button. Lots of possibilities!
School of Motion did a great write-up on Master Properties as well: https://www.schoolofmotion.com/blog/master-properties-after-effects/
- John, After Effects Engineering
Ryan Grant commented
Oh! Now I see. I thought master properties are a one time thing for templates, but it does show as the layer's properties for animation and expression. Each layer instance can have its own master properties set independently from each other. Thanks Steve!
Steve Skazenski commented
Is this something you could do with Master Properties/Essential Graphics?