Expression for in out opacity change

[Andrew Kramer]

Harry Frank made this nice script that works well:

transition = 40
tSecs = transition / ( 1 / thisComp.frameDuration);
iStart = thisLayer.inPoint
oStart = iStart + tSecs;
oEnd = thisLayer.outPoint
iEnd= oEnd- tSecs;
halfPoint = (iEnd – iStart) / 2;
if (time < halfPoint){ linear(time, iStart, oStart, 0, 100) }else{ linear(time, iEnd, oEnd, 100, 0) } Just paste it into the opacity expression and change the transition amount as needed. Thanks Harry! Best, Andrew Kramer

[Mike Clasby]

Here’s a post, with a Dan expression (second post), that does what you want I think.

https://forums.creativecow.net/cgi-bin/new_read_post.cgi?forumid=2&postid=877561

Just change the expression to:

fadeInTime = .5; // fade in time (seconds)
fadeOutTime = .5;

Math.min(linear(time,inPoint,inPoint + fadeInTime,0,100),linear(time,outPoint – fadeOutTime,outPoint,100,0))

[Aharon Rabinowitz]

Thank! Both of these work great. What if you wanted to only fade in or only fade out. I tried futzing around with this stuff, but couldn’t figure what parts had to go.

Man, I love this forum.

—————————————-
Aharon Rabinowitz
aharon(AT)yahoo(DOT)com
http://www.allbetsareoff.com
—————————————-
Creative Cow Master Series DVD
particleIllusion Fusion Volume 1
available @ http://www.pIllusionFusion.com

[Andrew Kramer]

With Dan’s script I would just set the fadeout time to 0 or whichever. Nice script btw.

[Andrew Kramer]

Oh and then if you want to only fade out, change the first 0 in the 3rd line of code to 100 so that no matter what the fadeInTime is, it will remap the value to 100-100 so no change, just opaque.

Math.min(linear(time,inPoint,inPoint + fadeInTime,100,100),linear(time,outPoint – fadeOutTime,outPoint,100,0))

[Colin Braley]

Fade in only…

fadeTime = 10;//frames
linear( time, inPoint, inPoint + framesToTime( fadeTime ), 0 , 100);

Fade out only…

fadeTime = 10;//frames
linear( time, outPoint – framesToTime( fadeTime ), outPoint, 100 , 0);

or if you want to be able to do fade in, fade out, or both within one expression just change the values of fadeIn and fadeOut in the following expression…

//–
fadeTime = 10; //frames
fadeIn = true;
fadeOut = false;
//–
if ( ! fadeIn && ! fadeOut )
{
100
}else if ( fadeIn && ! fadeOut) {
linear( time, inPoint, inPoint + framesToTime( fadeTime ), 0 , 100);
}else if ( fadeOut && ! fadeIn ) {
linear( time, outPoint – framesToTime( fadeTime ), outPoint, 100 , 0);
}
else{
if( time > this.inPoint + framesToTime( fadeTime ) )
linear( time, outPoint – framesToTime( fadeTime ), outPoint, 100 , 0);
else
linear( time, inPoint, inPoint + framesToTime( fadeTime ), 0 , 100);

}

Enjoy

~Colin

[Mike Clasby]

Yeah, with Dan’s, 0 for FadeOutTime seems to work, but 0 for FadeInTime leaves the layer at 0% opacity the whole clip, but 0.01 gives 0% at the inpoint, then to 100% at the second frame into the clip, so it’s off by one frame. Maybe Dan has a fix.

[Mike Clasby]

Thanks.

[Tony Kloiber]

Dan gave me that expression a couple years ago when I need to animate several hundred still files. Man did it save me some time on that project.

Thank you again Dan.

TonyTony

[Aharon Rabinowitz]

That’s what I love about After Effects – also known as the program that asks: how many ways can you skin a cat?*

Thanks folks!

Aharon

*Please note that the writer of this post does not support the skinning of actual cats.

—————————————-
Aharon Rabinowitz
aharon(AT)yahoo(DOT)com
http://www.allbetsareoff.com
—————————————-
Creative Cow Master Series DVD
particleIllusion Fusion Volume 1
available @ http://www.pIllusionFusion.com