• Adobe After Effects

  Property manipulation with expressions

  Posted by Rob Parker on August 20, 2020 at 8:24 am

  Hi! I’m really new to using expressions on after effects.

  So basically I have 2 problems to solve…
  1. I was trying to make the opacity of a layer go to zero when the amount of a blur goes to 0 as well. I’m assuming this will use an if else statement. But really I don’t know how to make these 2 properties interact.
  2. I want to increase layer2’s blur amount by 50 whenever I increase layer1s blur amount (and hopefully decrease L2’s blur amount when I decrease L1’s).

  Hopefully if I make L1’s blur amount to 0, it’ll trigger L2’s opacity to 0 as well.

  Hope this makes sense! So far I was working with slider controls to make these things work. But its a bit too much if I have 3 layers that’ll interact with each other. I was hoping to have 1 master slider control to adjust the layer’s properties.

  Thank you so much! Looking forward to hearing from you guys! 🙂

  Filip Vandueren replied 6 years, 1 month ago 2 Members · 1 Reply
• 1 Reply

• 

  Filip Vandueren

  August 20, 2020 at 11:16 am

  You can use just 1 slider, but every propery you want to control needs its own expression.
  An expression can not set another property’s value.

  In your example it could be as simple as:

  Blur Radius:
  thisComp.layer(“Controller”).effect(“Slider Control”)(“Slider”);

  Opacity:
  if (thisComp.layer(“Controller”).effect(“Slider Control”)(“Slider”).value < = 0) 0;
  else 100;

  Layer 2’s blur:
  thisComp.layer(“Layer 1”).effect(“Fast Box Blur”)(“Blur Radius”)+50;

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