• Adobe After Effects Expressions

  Expression that checks if Effect on another layer is present

  Posted by Daniel Hashimoto on March 6, 2019 at 8:53 pm

  I’m trying to create an effect that sets the position of a lens flare to the location of someone’s pupil if you’ve run the Detailed Face Tracker on a layer below – however, I’d like the expression to check whether the Face Tracker effect exists first, and if not, give a different default result.

  So I think I need an if/else to check whether that layer has the effect?

  I was thinking something like this where the this expression is on the location of a lens flare on a Black Solid, above a layer “SOURCE”. Desired output is the Right Pupil location (which works on its own) if the Source layer has the “detailed Face Tracker” effect applied – but will return [0,0] if no effect is present.

  Thank you for your help!

  if(thisComp.layer("SOURCE").effect("Face Track Points")("Right Pupil"))==null){[0,0]}else{thisComp.layer("SOURCE").effect("Face Track Points")("Right Pupil")}


  – Daniel Hashimoto
  \”Action Movie Dad\”

  Daniel Hashimoto replied 7 years, 2 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Oleg Pirogov

  March 7, 2019 at 12:28 am

  Since a reference to non-existent property raises an exception, you can use try-catch:

  var someVar;
  try{
  someVar =thisComp.layer("SOURCE").effect("Face Track Points")("Right Pupil");
  }
  catch(err){
  someVar=[0,0];
  }
• 

  Daniel Hashimoto

  March 7, 2019 at 2:10 pm

  Thank you so much! That’s it!

  – Daniel Hashimoto
  \”Action Movie Dad\”

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