Combinations / permutations on after effects

[Dan Ebberts]

I think there would be 504 permutations (9*8*7) and code like this should generate all of them:


for (var i = 1; i <= 9; i++){
for (var j = 1; j <= 9; j++){
if (j == i) continue;
for (var k = 1; k <= 9; k++){
if ((k == i ) || (k == j)) continue;
// do stuff
}
}
}


The code to actually moves the footage into the comp is going to depend on how you have things organized.

I hope that gets you started.

Dan

[Gon Perdigao]

Thanks Dan you rock!!

But why do you say that should be 504 permutations (9*8*7) i don’t understand where comes the 9*8*7 ?

And by the way where do i apply the code? To each layer or to a comp with all the layers inside?

Thanks a lot for all the help!

[Dan Ebberts]

The 9*8*7 comes from 9 choices for the first slot, which leaves 8 choices for the second slot, which leaves 7 choices for the third slot.

You probably wouldn’t use that code unless you put together a script to build the comp for you.

If you set up the comp by hand, with copies of all nine footage items in each of the three slots (assume slot 1 is layers 1-9, slot 2 is layers 10-18, and slot 3 is layers 19-27), you could use an opacity expression like this to calculate which layers should be visible, based on the current time:

dur = 10;
maxPerm = 9*8*7;
curPerm = Math.floor(time/dur)%maxPerm;
i = Math.floor(curPerm/56)+1;
j = Math.floor(curPerm%56/7)+1;
k = curPerm%7+1;
if (j >= i) j++;
if (k >= i) k++;
if (k >= j) k++;
if ((index == i) || (index == j+9) || (index == k+18)) 100 else 0

This should give you a different permutation every 10 seconds.

Dan