[Dan Ebberts]

>is it possible to resize a composition with an expression?

No. An expression can’t change anything except the value of the property hosting the expression. That tutorial shows you how to set up expressions to automatically resize things when you change the comp size.

Dan

[Dan Ebberts]

That property has a custom data type so I’m guessing you can’t link it anything except maybe the same parameter from another instance of that effect.

Dan

[Dan Ebberts]

You don’t have to use linear()–you can do that same calculation by hand, but you still have to deal with the time of the last frame being comp duration minus one frame.

Dan

[Dan Ebberts]

>So what you mean by this is interpolating to the last-1 frame instead of last frame. Right ??

No, the last frame. Try this. Create a 1-second 30 fps comp. Drag the time indicator all the way to the right and look at the time for the last frame. 00:29, right? Now hit the Page Down key. The time goes to 01:00, but you are now outside of the comp.

Dan

[Dan Ebberts]

You can quickly fix everything by switch to the Legacy ExtendScript expression engine:

File > Project Settings > Expressions

If you want to fix them for the JavaScript engine, change all instances of radians_to_degrees to radiansToDegrees, and change all the single-line if/else statements to multi-line:

e.g. change:

if ( Mat == 1) mTol else 255;

to:

if ( Mat == 1)
mTol
else
255;

or use brackets:

if ( Mat == 1) { mTol } else { 255 };

or use the ternary operator

Mat == 1 ? mTol : 255;

Dan

[Dan Ebberts]

Something like this maybe:


rate = 500;
rampDur = value[0]/rate;
freq = 3;
decay = 5;
w = freq*Math.PI*2;

if (time < (inPoint+outPoint)/2){
if (time < (inPoint + rampDur)){
x = linear(time,inPoint,inPoint+rampDur,-width/2,value[0]);
}else{
t = time - (inPoint+rampDur);
x = value[0] + rate*Math.sin(t*w)/Math.exp(t*decay)/w;
}
}else{
if (time > (outPoint - rampDur)){
x = linear(time,outPoint-rampDur,outPoint,value[0],thisComp.width+width/2);
}else{
t = (outPoint - rampDur) - time;
x = value[0] + rate*Math.sin(t*w)/Math.exp(t*decay)/w;
}
}
[x,value[1]]


Dan

[Dan Ebberts]

What do you have for scale?

Dan

[Dan Ebberts]

Oops, there’s a mistake in there. Yellow should be:

yellow=[1,1,0,1];

In expressions, the color values are normalized to be between 0.0 and 1.0 and expressed as arrays:

[red,green,blue,alpha]

So red is [1,0,0,1], white is [1,1,1,1] etc.

Dan

[Dan Ebberts]

It’s not clear how you want the colors to change exactly, but this example would change from red to green (with yellow in the middle) across the full range of the slider:


Col=thisComp.layer("100%").effect("Control Number")("Slider");
red=[1,0,0,1];
yellow=[1,1.5,0,1];
green=[0,1,0,1];
if (Col < 50)
linear (Col,0,50,red,yellow)
else
linear (Col,50,100,yellow,green)


Dan

[Dan Ebberts]

Try it this way:

t = thisComp.duration – thisComp.frameDuration;
linear(time,0,t,0,360)

Say your comp duration is 10 frames. The first frame would be frame 0 and the last would be frame 9. Frame 10 would be one frame beyond the end of your comp, so you want your linear() range to end one frame before the duration of your comp. I think ☺

Dan