Expressions – variables

[Deathwolf]

arg, real sorry for the double post, stupid thing said “could not connect to db” so i assumed it had not posted

[Filip Vandueren]

You can always assign an expression to an expression-controller like a slider on a null,
then other expression reference that slider, and they will get the calulated value.
There is no way to set the value of the slider from outside of that slider’s expression, so you can have the expression for opacity store a value in a slider.
So you have to think the other way around, and do all calculations in the sliders’ expression.

As per the text-expressions, you can assign an expression to the source-text value of a text-layer, if the outcome of that expression is a number or more importantly a string, it will be displayed.
You can do this for an invisible text-layer and have another layer reference that value. Also, you can store different texts in different keyframes and then retrieve the values of those keys.

What exactly do you want to achieve, because this is just theoretical and very general, there may be other ways around your problem.

[Deathwolf]

well all of this was pretty general
and about sliders, i dont think they can be used cross comp(which was my question)
but i might be wrong

about text, what is the name of the variable that controls the text?

[Filip Vandueren]

You can reference them no problem, it gives a syntax like this:

comp("Comp 2").layer("Null 1").effect("Slider Control")("Slider")

the parameter you want for text is called “Source Text” or “text.sourceText” in Javascript

Twirl open the Text layer, then Text and it’s the first param you see right befor path options.