• Adobe After Effects Expressions

  a little help understanding my first expressions

  Posted by Kevin Nally on December 23, 2009 at 6:31 pm

  hi i recently got a tutorial on using a particular expression that allows simpler animation in creating a fan like effect.i have managed to get over to basics and got everything working but i would like to maybe push experimenting a bit more and i’d really appreciate any help

  1) Would someone be able to give me a broken down explanation of what this code is doing “thisComp.layer(“Tail feather 4”).transform.zRotation.valueAtTime(time-thisComp.layer(“Expression Control”).effect(“Offset”)(“Slider”));” im a complete beginner at expression you see..

  2) In order for this to work i have to parent each layer to the one above. But this means that all my layers are on the same Zposition and i would really love to be able to maybe incorporate an orbiting 3d camera for some nice effects. would any1 know of an expression i could add that could allow me to do this?

  3) is there a simpler alternative way of doing this animation?

  link to pdf tutorial
  https://mos.futurenet.com/pdf/computerarts/ART168_tut_ae.pdf

  page which includes link to support files (mov, aep + psd)
  https://www.computerarts.co.uk/tutorials/3d__and__animation/swift_and_simple_animation

  thanks for any help you can give

  thisComp.layer("Tail feather 4").transform.zRotation.valueAtTime(time-thisComp.layer("Expression Control").effect("Offset")("Slider"));

  Kevin Nally replied 16 years, 9 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Michael Szalapski

  December 28, 2009 at 10:43 pm

  You can move your layers around in Z space if you want. Sure, move the top one back in Z-space and all the little children will follow it, but then move the next on and the next one until you have them all where you want them. As long as you start with the topmost parent, you’ll be fine.

  Basically that expression is telling AE to make that layer’s rotation do what the other layer’s rotation does, but to wait a bit before it does it. The slider tells it how long to wait before it starts doing what the other layer did.

  The first part of the expression tells the rotation value to be the rotation of a certain layer (in this case, you’re specifying it’s parented layer).
  valueAtTime tells it to pull the value from a certain time
  time-thisComp.layer("Expression Control").effect("Offset")("Slider") tells it that the certain time is the current time minus whatever number the slider is sitting at.

  Does that make sense?

  You might want to check out the expressions section of MotionScript.com. It’s a site full of amazing stuff written by the genius known as Dan Ebberts.

  – The Great Szalam
  (The ‘Great’ stands for ‘Not So Great, in fact, Extremely Humble’)

  No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.
• 

  Kevin Nally

  December 30, 2009 at 9:36 pm

  thank you thats a great explanation. this should be great fun now to play with. thank you for the link, ill make sure to check it all out.
  cheers my humble amigo

Reply to this Discussion! Login or Sign Up