• Adobe After Effects Expressions

  scaling with expressions

  Posted by Clemensk on May 9, 2006 at 4:53 pm

  I have tons of layers which have to be scaled from 0 to 100 over a length of 10 frames, starting at the inpoint of the layers and scaled from 100 to 0 at the end.
  Doing this with expressions could save me a lot of time but i can’t figure out how to do this.

  Anybody can help?

  best regards
  Clemens

  Dan Ebberts replied 20 years, 4 months ago 2 Members · 4 Replies
• 4 Replies

• 

  Clemensk

  May 9, 2006 at 5:52 pm

  i found a simple solution myself but maybe you can help me to improve the script. the layer is scaled now linear from 0 to 63 beginning at the inpoint. It would surely look better if it goes from for example from 0 to 80 in 10 frames and from 80 to 63 in 3 frames.

  any ideas.

  best regards
  Clemens

  adjust = 90

  temp= time – inPoint;
  temp = temp * adjust
  temp =Math.min(temp, 63) ;

  outtemp= outPoint -time;
  outtemp = outtemp * adjust
  outtemp =Math.min(outtemp, 63) ;
  temp =Math.min(temp, outtemp) ;

  [temp,temp]
• 

  Dan Ebberts

  May 9, 2006 at 6:46 pm

  I’m not sure what your expression does, but I think this one does what you originally asked for:

  f = 10; // number of frames to ramp
  t = f*thisComp.frameDuration;
  s = Math.min(linear(time,inPoint,inPoint+t,0,100),linear(time,outPoint-t,outPoint,100,0));
  [s,s]

  Dan
• 

  Clemensk

  May 9, 2006 at 7:07 pm

  thank you for your reply.

  nice script, looks much better than the one i figured out, but basically they do the same. Do you have a solution for my second question too? some sort of easing which slightly overshoots the target value.
  for example 0 > 120 > 100

  ???

  Clemens
• 

  Dan Ebberts

  May 9, 2006 at 8:36 pm

  OK – try this:

  f1 = 10; // ramp on/off frames
  f2 = 3; // overshoot frames

  max = 80; //maximum scale value
  hold = 63; // hold scale value

  t1 = f1*thisComp.frameDuration;
  t2 = f2*thisComp.frameDuration;

  if (time <= inPoint + t1 + t2){ s = Math.min(linear(time,inPoint,inPoint+t1,0,max),linear(time,inPoint+t1,inPoint+t1+t2,max,hold)); }else{ s = linear(time,outPoint-t1,outPoint,hold,0); } [s,s] Dan

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