• Adobe After Effects Expressions

  random() generates a different number after closing and opening AE again

  Posted by Dino Muhic on December 9, 2010 at 12:51 pm

  Hi,

  I have layers which are positioned at specific coordinates and which implode into the destined coordinate from a random point in space. Imagine a reversed explosion.
  The camera should fly through the randomly placed layers at the beginning

  Since there are a lot of layers I wanted to position them randomly and made a script using random() but after I closed the project and opened it again, the random values where different then before.

  is there a way to place them randomly and let them implode but in a way where they STAY at the value they got assigned to?

  I assume I need to “bake” the randomly generated numbers but dont know how.

  I don’t mean using seedRandom(index,true)! My problem is, that I animated the camera through the randomly generated layers and after restarting they were at different positions and I had to animate the camera again and again.

  Any ideas?

  Thanks

  Kevin Camp replied 15 years, 5 months ago 3 Members · 4 Replies
• 4 Replies

• 

  Dan Ebberts

  December 9, 2010 at 2:14 pm

  It would help to see your expression.

  Dan
• 

  Dino Muhic

  December 9, 2010 at 2:22 pm

  Hi Dan,

  I have a Null object with a slider which controls the “explosion”, the code below is in the position value of all layers.

  I got the same for all rotation axes

  seedRandom(index,true);

  add= thisComp.layer("Null 1").effect("Dispersion")("Slider");
xVal =transform.position[0]+random(add*-1, add);
yVal = transform.position[1]+random(add*-1, add);
zVal = transform.position[2]+random(add*-1, add);
[xVal,yVal,zVal]

  Dino Muhic – Media Producer
  VFX – Motion Graphics – Web-Design – Or just ART
  http://www.dinomuhic.com
• 

  Dan Ebberts

  December 9, 2010 at 2:55 pm

  I don’t get that behavior on just saving and reopening the project. However, if you make any changes to the number of layers all your random values will move around. One note on your expression – I wouldn’t use “add” as a variable name because there is already a vector math operator named “add”. I think your expression can be simplified to this:

  seedRandom(index,true);
  d= thisComp.layer(“Null 1”).effect(“Dispersion”)(“Slider”);
  value + random([-d,-d,-d],[d,d,d])

  Dan
• 

  Kevin Camp

  December 9, 2010 at 4:28 pm

  also, if you want to bake the expression values, you could use animation>key frame assistant>convert expression to keyframes

  Kevin Camp
  Senior Designer
  KCPQ, KMYQ & KRCW

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