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Blinking speed and offset
I have two problems with a blinking expression.
I want a layer to blink and then the blink gradually slow down.I tried this expression
freq =effect("frequency")("Slider");
n = Math.sin(time*freq);
if (sw<=0) 0 else 100and this one
freq = effect("frequency")("Slider");
amp = 100;
n = freq.numKeys;if (n > 0 && freq.key(1).time < time){
accum = freq.key(1).value*(freq.key(1).time - inPoint);
for (i = 2; i <= n; i++){
if (freq.key(i).time > time) break;
k1 = freq.key(i-1);
k2 = freq.key(i);
accum += (k1.value + k2.value)*(k2.time - k1.time)/2;
}
accum += (freq.value + freq.key(i-1).value)*(time - freq.key(i-1).time)/2;
}else{
accum = freq.value * (time - inPoint);
}
sw = value + amp * Math.sin(accum * Math.PI * 2);
if (sw<=50) 0 else 100;which I found on motionscript
It works until my frequency is constant but when I use keyframes in the slider the blinking speeds up and then speeds down again when it reaches the new value...
How can I make the blink gradually slow down?
Moreover I want another layer to blink at the same speed but not in sync... Anyone can help?
Thanks -
3 Replies
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Better blink expressions here:
https://forums.creativecow.net/thread/227/14265
Although you’ll have to connect the values to sliders that you can then animate.
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Thanks for your answer.
I tried the expression you mentioned but, for some reason, it does work if I link the values to a slider.What I’m trying to achieve is not a random blinking but a light constantly flashing at some speed then constantly slowing down to another value (eventually speeding up again at the original value).
At the moment I pre-rendered a clip with my flashing light and used the timewarp effect but I’m guessing if it’s possible to do it using expression in some way. -
Your original expression (fixing the “sw” to “n”) works fine for what you describe.
freq =effect("frequency")("Slider");
n = Math.sin(time*freq);
if (n<=0) 0 else 100If you animate the slider the blinking will speed up or slow down, unless you are using hold keyframes (which keep a constant value until the next keyframe).
If you want another layer to blink differently, you can add something to the time value of the second line, for example
n = Math.sin(time*freq+100*index);
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