seed random for randomness

[Mylenium]

[ryandrew] “hello guys, another question about expression, as far as i know, seedRandom can control the way how randomness(noise pattern) is generated, but why it cannot control the random in AE expression? what i mean is, if i write: seedRandom(1,true); wiggle(1,100) and apply to say opacity of all layers, then they will have the opacity change in the same way, but not for seedRandom(1,true); random(100). each layer will change differently even they have the same seed number? thanks”

What point would there be, if random() returned the same values for each layer with a fixed seeding? The seed for the random function is picked from a generic pool (since it is still dependent on AE’s global time, just frozen) while wiggle always calculates its own random noise. It’s really not clear why you would want it any other way because then it would be useless.

Mylenium

[Pour Myl

[Ryan Chan]

thanks Mylenium, as first i supposed the seed can also control the pattern of randomness for RANDOM, and now i understand how it works.

[Dan Ebberts]

It would indeed be extremely useful if you could force random() to produce the same random sequence in different layers and properties. I think seedRandom needs a third parameter – global = true, but alas, as you discovered, it doesn’t exist.

Dan

[Ryan Chan]

thanks

[Filip Vandueren]

One could use the noise() function for “a global random fixed number”.

just feed the seed as it’s only parameter. noise(seed), noise([seed,seed]) or even noise([seed,seed,seed])

Granted, this is not a true “seed”-value, rather the “position” in a “noise-field”,
and also not a true random number, (e.g. noise(100) and noise(101) will most likely have similar results)
but it’s a start

just choose either “seed”-values that aren’t too closely spaced, or multiply them by a quite large prime number.

check out Dan’s tutorial called
“noise()