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a question about variables

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Assaf Goldlust
a question about variables
on Jan 12, 2018 at 11:25:53 am

so im trying to learn about expression and about how they work from the book "after effect expressions" by marcus geduld (2009)
and when he talked he said something i have hard time understanding:

he was using the expression:
controller=transform.opacity;
controller

and applied it to rotation
and he said's that whats matter is the last statement.
that the first statement
(controller=transform.opacity;)
is only storing information from the opacity property.
but he doesn't do anything else without the second statement (controller in this case)
that tells after effect to use it information.


the confusing part is: when i erase the second statement. and stay only with the first one the rotation is still responding to the changes i do in opacity, wasent he sop post only to restore information and not really show it to me?

whats difference the second statement is doing?!


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Steve Sierra
Re: a question about variables
on Jan 12, 2018 at 12:49:25 pm

Hi,

You're right, it does still work...

On the other hand, if you write :
"var Controller = transform.opacity", then you need to write "Controller" after it or it won't work, illustrating Marcus Geduld's point.

I guess Ae expressions were created to do that, not sur it works in a script ?

Hope this helps a bit...

Cheers !


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Assaf Goldlust
Re: a question about variables
on Jan 12, 2018 at 1:12:01 pm

I guess Ae expressions were created to do that, not sur it works in a script ?

not trying to be rude but that line had me wonder if you are sure about what your saying.
or simply making guesstimations


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Dan Ebberts
Re: a question about variables
on Jan 12, 2018 at 2:16:53 pm

An expression just applies the value of the last statement executed to the property hosting the expression. So, these three expressions applied to the rotation property have the exact same result:

controller=transform.opacity;
controller

or,

controller=transform.opacity;

or,

transform.opacity;



Dan



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Assaf Goldlust
Re: a question about variables
on Jan 13, 2018 at 11:19:50 am

An expression just applies the value of the last statement executed to the property hosting the expression. So, these three expressions applied to the rotation property have the exact same result:

controller=transform.opacity;
controller

or,

controller=transform.opacity;

or,

transform.opacity;



Dan


its kind of sounds tome like its at odds with what he saids.

im uploading the part were he speaks about it. maybe it would help understanding becuse if to be honest im not sure i explained it right.
[IMG]http://i63.tinypic.com/1zldh7a.png[/IMG]

[IMG]http://i65.tinypic.com/2640ufs.png[/IMG]


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Dan Ebberts
Re: a question about variables
on Jan 13, 2018 at 3:35:17 pm

>its kind of sounds to me like its at odds with what he saids.

Yup.

Did you try it? I think you'll find it's exactly as I described.

Dan



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Assaf Goldlust
Re: a question about variables
on Jan 15, 2018 at 9:36:41 am

yes i did this is why im cofused about it. what did he ment when he was saying that the second statement is the one after effect use to controll the expression.

and that the first statement only tells the computer to store a variable in a value?

P.S im posting the screenshots becuse i did wrong previusly







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Dan Ebberts
Re: a question about variables
on Jan 15, 2018 at 5:23:56 pm

This expression:

controller = transform.opacity;

does, in fact, produce a result.

Dan



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