Adding Fade In & Out using Scripting

[John Cuevas]

Autofade

Johnny Cuevas, Editor
Thinkck.com

“I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
—THOMAS EDISON on inventing the light bulb.

[Walter Soyka]

You could also apply this expression, so that the fade will update even if the layer timing is changed later:

// set this value to the length of the dissolve you want, in seconds
dissolveTime = 3;

// if we don't have enough time to do both full dissolves the way we want, set the dissolve time to half the total duration.
if (outPoint - inPoint < dissolveTime * 2) dissolveTime = (outPoint - inPoint)/2;

// use linear interpolation to go from 0 to the nominal opacity value (100 by default, but adjustable or keyframable) as long as we're within dissolveTime seconds of the layer's in point,
// and vice versa for the out point. Otherwise, simply return the nominal value.
if (time-inPoint <= dissolveTime) linear(time-inPoint,0,dissolveTime,0,value)
else if (outPoint-thisComp.frameDuration-time <= dissolveTime) linear(outPoint-thisComp.frameDuration-time,0,dissolveTime,0,value)
else value;

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
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[Erik Waluska]

There is also a “Fade In+Out – frames” preset in the “Behaviors” section that fades in and out by however many frames you enter, base on the in and out points of the layer. Harry Frank has a preset called “graymachine auto fade” on his site that uses layer markers to determine the fade duration.

Erik Waluska
EAWmedia