• Adobe After Effects Expressions

  Expression Won’t Render

  Posted by Benny Christensen on September 30, 2005 at 6:18 pm

  Hi,

  My name is Benny and I’m very Expressions Challenged.

  I’m using AE6.5 with a G5 dual 2gig with lots of RAM.

  I’ve modified an expression from Dan Ebberts site to make some blocks move randomly along the X axis. It plays fine, but when I try to render it starts popping up all sorts of errors.

  Any ideas?

  Thanks.

  Benny Christensen
  Producers Playhouse
  Oklahoma City, OK

  G5 Dual 2 Gig – 10.4.2 – 4 Gb RAM – FCP 5.02 – KONA2 – ATTO UL4D – HUGE 320RX – Convergent Designs SD-Connect

  Dan Ebberts replied 20 years, 7 months ago 3 Members · 4 Replies
• 4 Replies

• 

  Dan Ebberts

  September 30, 2005 at 8:10 pm

  What do the error messages say?

  Dan
• 

  Steve Roberts

  September 30, 2005 at 8:14 pm

  … and can you copy and paste the expression (from your project) in your post?

  Steve 🙂
• 

  Benny Christensen

  September 30, 2005 at 8:37 pm

  First – Here is the error message After Effects Warning: Class ‘global’ has no property or method named ‘start’. Error ocurred at line 18. Expression disabled.

  I found that if I start the render somewhere after 3 or 4 seconds it would work.

  Second – Here is the expression

  tMin = .25; //minimum segment duration
  tMax = 1.0; //maximum segment duration
  minVal = [0.*thisComp.width, 0*thisComp.height];
  maxVal = [1*thisComp.width, 0*thisComp.height];

  end = 1;
  j = 2;
  while (time >= end){
  j ++;
  seedRandom(j,true);
  start = end;
  end += random(tMin,tMax);
  }
  endVal = random(minVal,maxVal);
  seedRandom(j-1,true);
  dummy = random(); //this is a throw-away value
  startVal = random(minVal,maxVal);
  ease(time,start,end,startVal,endVal)

  Thanks.
• 

  Dan Ebberts

  September 30, 2005 at 9:21 pm

  Yeah, it looks like you made some changes to the expression that cause start to be undefined near the beginning of the comp. If you just want random movement in the x direction, you could try this one:

  segMin = .3; //minimum segment duration
  segMax = .7; //maximum segment duration
  minVal = 0;
  maxVal = thisComp.width;

  end = 0;
  j = 0;
  while ( time >= end){
  j += 1;
  seedRandom(j,true);
  start = end;
  end += random(segMin,segMax);
  }
  endVal = random(minVal,maxVal);
  seedRandom(j-1,true);
  dummy=random(); //this is a throw-away value
  startVal = random(minVal,maxVal);
  y = position[1];
  ease(time,start,end,[startVal,y],[endVal,y])

  Dan

Reply to this Discussion! Login or Sign Up