• Adobe After Effects Expressions

  How to check by name if a slider exist on a layer ?

  Posted by Tal Arbiv on December 25, 2016 at 10:18 pm

  I know how to check for layer by name but property?
  and also, how can i check the number of dimensions on an effect property?

  Thanks

  if (myComp.layer(&quotLayer Name").Effect("ADBE Slider Control").property("Slider") == null){
var exists =false;
}else{
var exists =true;
}

  Tal Arbiv replied 9 years, 8 months ago 2 Members · 8 Replies
• 8 Replies

• 

  Dan Ebberts

  December 26, 2016 at 7:49 am

  Expression or script? Something like this should work for an expression:

  
try{
thisComp.layer("Layer Name").effect("Slider Control")("Slider");
exists = true;
}catch(err){
exists = false;
}


  It would be similar for a script.

  Dan
• 

  Tal Arbiv

  December 26, 2016 at 6:41 pm

  Thank you so much Dan!

  yes its scripting…

  The second question i had was how can i tell how many dimensions a property has ?
  i’m applying an expression to layers and i want the expression to change according to the dimensions…

  lets take wiggle for example
  if there is a better way to do this please share…

  Thanks a lot again!

  var expression1 = "wiggle (10,10)";
var expression2 = "w=wiggle (10,10);[w[0],w[0]]";
var expression3 = "w=wiggle (10,10);[w[0],w[0],w[0]]";

  for (i=0; i <= sellayers.length-1; i++){
for (p=0; p < = selprop.length-1; p++){
//missing query
selprop[p].expression = //expressionX;
}

• 

  Dan Ebberts

  December 26, 2016 at 8:15 pm

  I think I’d do something like this:

  var val = myProp.valueAtTime(0,false);
  var numDim = val instanceof Array ? val.length : 1;

  Dan
• 

  Tal Arbiv

  December 27, 2016 at 1:09 am

  i tried it and it breaks…

  something about that valueAtTime method stops the loop that goes through the layers

  var myComp = app.project.activeItem;
var sellayers = myComp.selectedLayers;
var selprop = myComp.selectedProperties;

  for (i=0; i <= sellayers.length-1; i++){
for (p=0; p <= selprop.length-1; p++){
selprop[p].expression =("1"); //WORKS GREAT
alert (selprop[p].valueAtTime(0,false)); // DOSNT WORK breaks the loop after the first layer
}
}

• 

  Dan Ebberts

  December 27, 2016 at 2:11 am

  You may have some properties selected that can’t have expressions, so I’d make sure that myProp.canSetExpression is true before doing the other tests.

  Dan
• 

  Tal Arbiv

  December 27, 2016 at 11:38 am

  This will be great to add thanks.
  but the problem wasn’t the expression. putting expressions works great for all layers and all properties, the valueAtTime line doesn’t.
  what am i missing?
• 

  Dan Ebberts

  December 27, 2016 at 4:59 pm

  I don’t think you want to loop both selected layers and selected properties. This seems to work for me with everything I could throw at it:

  
var myComp = app.project.activeItem;
var selprop = myComp.selectedProperties;

  for (p=0; p <= selprop.length-1; p++){
if (selprop[p].canSetExpression){
selprop[p].expression =("value");
alert (selprop[p].valueAtTime(0,true));
}
}


  Dan
• 

  Tal Arbiv

  December 27, 2016 at 11:38 pm

  wow, i was sure i tried that at the beginning…
  maybe i needed some operation to be made at the same time to the layers… anyway, it works now,
  really appreciate your help!

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