Disable or Enable an Expression with a Checkbox Control

Adobe After Effects Expressions

Disable or Enable an Expression with a Checkbox Control

Posted by Nick Mara on September 29, 2020 at 11:38 pm

Hi Everybody,

Is there an expression to Enable/Disable an expression with a Checkbox Control?

So here is my situation:

I have an expression on the “End” property of a Trim Path and the same expression on the “Start” property of the same Trim Path.

I would like to know if there’s a way to turn on the expression of the “End” property while disabling the expression on the “Start” property via a Checkbox Control.

Here is what I mean:

https://youtu.be/hxEXAh4qf6w

I hope everything it’s clear enough.

I would really appreciate your help.

Thanksss

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Nick Mara replied 5 years, 7 months ago 3 Members · 5 Replies
5 Replies

Brendon Murphy
September 30, 2020 at 2:58 am

Add a checkbox effect to Shape_Base, then do this on the start parameter:

if (effect(“Checkbox Control”)(“Checkbox”)==1){

//put the original start expression here

}else{value};

And then this on the end parameter:

if (effect(“Checkbox Control”)(“Checkbox”)==0){

//put the original end expression here

}else{value};
Brendon Murphy
September 30, 2020 at 3:01 am

make sure to delete the “//put the original expression here”, including the slashes!

Stephen Dixon

September 30, 2020 at 3:18 am

Simple, use an if() statement

let chkbx = [link to checkbox control, use the pickwhip];
if (chkbx.value){
    [your expression here]
} else {
    value //returns the keyframed value without the expression
}

For the other layer use the boolean not operator: “!“

 if (! chkbx.value){

Nick Mara
September 30, 2020 at 7:53 am

Hey Brendon,

Thank you so much for providing me this expression.

It works perfectly
Nick Mara
September 30, 2020 at 8:03 am
Hi Stephen,

Thanks for your answer !!

I put the first part of the expression on the “End” property of the Trim Path but I can’ t figure out where to put the boolean not operator: “!”
```
 if (! chkbx.value){
```
You wrote “For the other layer ” but the expressions are on the same layer not on two different layers.

Am I doing something wrong?

Thanks

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