alarm clock wiggle effect?

[Mike Clasby]

To get a Marker to trigger expressions, drop a marker where the alarm goes off (* on the numeric pad), then add the expression(s) below.

If you just want it to rattle around, jump up and down, put this expression on Position (Copy the expression, Alt-Click the Position Stopwatch, Paste, click outside the box):

amp=30; //amplitude (pixels)
freq=8; //frequency (cycles per second)
decay=0.8; //decay time (seconds)

// find previous marker

n = 0; // assume haven’t reached a marker yet
if (marker.numKeys > 0){
n = marker.nearestKey(time).index;
if (marker.key(n).time > time){
n–;
}
}

if (n > 0) t = time – marker.key(n).time else t =0;
a = amp*Math.sin(freq*t*Math.PI*2)/Math.exp(decay*t);
wiggle (a,a)

And to give it a rocking, rotation, motion add this to rotation:

amp=30; //amplitude (pixels)
freq=8; //frequency (cycles per second)
decay=0.8; //decay time (seconds)

// find previous marker

n = 0; // assume haven’t reached a marker yet
if (marker.numKeys > 0){
n = marker.nearestKey(time).index;
if (marker.key(n).time > time){
n–;
}
}

if (n > 0) t = time – marker.key(n).time else t =0;
a = amp*Math.sin(freq*t*Math.PI*2)/Math.exp(decay*t);
a

These are Dan Ebberts’ expressions (or modified form sthereof), change the amp, freq, and decay as needed, but do it the same for both expressions… although that’s probably not necessary.

[Mike Clasby]

OK, thinking about it, the above is a bit overkill. You could simply use a wiggle expression, controlled by a slider. Here’s how:

https://forums.creativecow.net/readpost/227/8953

Key-framing the slider to zero, stops the wiggle.

[David Lieberman]

thank you so much,

VERY HELPFUL!!! i’ve done a bit of action scripting on flash and was wondering how similar that is to AE expressions… is there any text source or good website where i can learn more about expressions for AE?

thanks again.

d