Expressions linked between comps

[herrostwald]

Hi,

just upgraded to CC 2017 and realized that I can't connect values through expressions between different comps anymore.

Example (in pre-Comp of a texture):

comp("Tunnel_1").layer("MIR").effect("Mir")("Scroll Y")

It's giving me funky error messages and is not working how it used to. Is it possible that this function is interrupted by the new collaboration feature?

Please try to fix this asap with the next update!!!

Thanks,

Conrad

[Rick Gerard]

I'm not having any problems yet. Could you give us a flow chart and some more details on how your comp is set up. Does the very same comp work in an earlier version? What are the error messages?

[herrostwald]

Hey Rick, thanks for your quick response.

The error message below doesn't help much because the comp "Tunnel_1" does exist in my project - so I assume AE just doesn't understand the value I'm feeding it.

I played around a bit more and it looks like the only values that cannot be linked to the Target Comp through an expression are the ones being altered by an expression in the Source Comp. Tried it in AE 2014 and the same error appears. I guess I never linked expression generated values between comps before - that explains my confusion.

But is there a way to "read" the expression-generated values in a Source comp and "clone" the value to a layer/effect in the Target comp?

Cheers!!!

[Rick Gerard]

What does your whole expression look like? There could be a line feed if you renamed the layer. You should be able to drag the pickwhip between comps if you split up the timelines by dragging one above the other or to the Effects Control Panel in the Tunnel1 comp if you lock it and get the expression to work.

[herrostwald · Accepted solution]

Hey Rick,

that's what I did and It works fine if you connect "regular" or animated values. Interestingly if you try to pick-whip an expression-modified value the lines in the expression are broken up into 3 lines, not the regular 1 line.

Anyways, I guess that's just a feature After Effects can't handle so now I know

[Rick Gerard]

If you have renamed layers in some versions of AE you force a line feed. This can be removed from the layer by selecting the layer name, pressing enter, then delete twice, then name the layer again.

If you expression looks like this:

comp("Tunnel_1").layer("MIR").effect("Mir")("Scroll Y")

some new code;

some other code;

Then you have a forced line feed that either must be fixed by editing the expression. You have to have a ; at the end of each line of code and you cannot force a line feed or the expression will break.

Again, if you showed me the exact expression in it's entirety then I could give you a better diagnosis.