• Adobe After Effects Expressions

  Generate an x,y,z position for 100 layers

  Posted by Kevin Church on March 10, 2010 at 10:37 pm

  I am looking for a way to generate an x,y,z position for 100 layers that remains constant through time. I have a pile of pictures that I want to place in different positions in 3D space without having to manually set the positions.

  I used the expression below, but the values are randomized each frame.

  Thanks in advance for any help!

  maxZ = 5000;
minZ = -5000;
maxX = 3000;
minX = -3000;
maxY = 2000;
minY = -2000;

  z = random(minZ,maxZ);
  x = random(minX,maxX);
  y = random(minY,maxY);

  [x,y,z]

  Kevin Church replied 16 years, 2 months ago 4 Members · 7 Replies
• 7 Replies

• 

  Dan Ebberts

  March 10, 2010 at 11:30 pm

  just add this at the top:

  seedRandom(index,true);

  Dan
• 

  Kevin Church

  March 10, 2010 at 11:41 pm

  Thanks Dan,

  I am new to After Effects and new there would be an easy solution. Just so I understand, the true part is what makes this not sensitive to time?

  Cheers,
  Kevin
• 

  Dan Ebberts

  March 11, 2010 at 12:04 am

  Yes, that’s correct.

  Dan
• 

  Kevin Church

  March 11, 2010 at 12:32 am

  Thanks so much!
• 

  Darby Edelen

  March 11, 2010 at 1:27 am

  Dan’s already got your back on seedRandom(index, true); but I thought I’d also mention that random(); will accept a pair of vectors/arrays, so you could simplify your code to:

  
seedRandom(index, true);
min = [-3000, -2000, -5000];
max = [3000, 2000, 5000];

  random(min, max);


  Darby Edelen
• 

  Lloyd Alvarez

  March 11, 2010 at 1:38 pm

  Using expressions is not the most efficient way to do this since expressions are evaluated for every
  layer at every frame. This is why I wrote a script to do this. The script only
  needs to he evaluated once at run time. https://aescripts.com/3d-layer-distributor/

  Lloyd

  https://aescripts.com
• 

  Kevin Church

  March 11, 2010 at 6:56 pm

  cool, thanks for the tip! That code is much cleaner.

  Lloyd, I am not too familiar with scripts but I like the theory. I’ll take a look at your link.

  Thanks everyone!

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