• Adobe After Effects Expressions

  hold an expression at it’s last value

  Posted by Roei Tzoref on December 5, 2016 at 10:50 am

  hey all you expression wizards ☺

  I wish to figure out how to stop an expression at it’s ending value: say I have a rotation of a layer set to time*30 and I want to create a checkbox control to hold it (and continue) every time I click it.

  so I have this:
  if (effect(“Checkbox Control”)(“Checkbox”)==1) time*30 else ?;

  what should I put after the else the makes it “stop at current time” so I can toggle this time expression on and off and keep my current position when I freeze it?

  thank you

  Roei Tzoref
  After Effects Artist & Instructor
  ♫ Ae Blues Tutorials

  Roei Tzoref replied 9 years, 8 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Dan Ebberts

  December 5, 2016 at 5:18 pm

  Something like this, probably:

  
chkBx = effect("Checkbox Control")("Checkbox");
n = 0;
if (chkBx.numKeys > 0){
n = chkBx.nearestKey(time).index;
if (chkBx.key(n).time > time) n--;
}
t = 0;
curTime = time;
if (n > 0){
for (i = n; i > 0; i--){
if (chkBx.key(i).value > 0){
t += (curTime - chkBx.key(i).time);
}
curTime = chkBx.key(i).time;
}
if ((curTime > 0) && (chkBx.key(1).value > 0)) t += curTime;
}else{
if (chkBx.value > 0) t = time;
}
t*30


  Dan
• 

  Roei Tzoref

  December 5, 2016 at 8:52 pm

  Thank you Dan. it works and I will keep it near. I was thinking this could be much simpler so I could tweak it to other manipulations as well – for example wiggle. here I was thinking that instead of my “?” there’s only a few letters of codes and that’s it. I can’t really get my head around this but blindly copy pasting it. guess this was heavy stuff.

  Roei Tzoref
  After Effects Artist & Instructor
  ♫ Ae Blues Tutorials

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