Simple Postion Random Expression

[Dan Ebberts]

Something like this:

seedRandom(index,true);
x = random(0,1500);
z = random(0,1500);
[x,value[1],z]

Dan

[Avrohom Kohn]

Thanks. That works. Could you just explain what this is for:

seedRandom(index,true);

Why couldn’t I just put in everything after that? I’m just trying to learn expressions and not just copy and paste every time.

Thanks.

Avrohom

[Avrohom Kohn]

And one more thing:

Every time I duplicate the layer, even the original randomizes again. Why doesn’t it stay at the position it already chose.

thanks.

Avrohom

[Dan Ebberts]

Try it – you can’t break anything. 🙂

What will happen is that the random position will change on every frame. seedRandom(seed,true) causes the same random numbers to be generated on each frame.

Dan

[Dan Ebberts]

Try using a constant for the seed rather than the layer index, like this:

seedRandom(1,true);

Dan

[Avrohom Kohn]

Ok. I was playing around with it. The problem is, the layers seem to be staying close to each other. I have 2 layers, they’re nicely spaced. When I duplicate layer 2, both layer 3 and layer 2 are rerandomized, and mose times they stick dangerously close to each other and sometimes close to the first layer as well. Is there a way to control the amount of randomness?

Avrohom

[Avrohom Kohn]

This last thing you mentioned (seedRandom(1,true); ) works much better. I didn’t see it before. Sorry.

I was playing around with different numbers instead of 1. 10 gives me better results. Could you just explain what it’s doing (what’s the random index of the layer, and what’s this number telling it)?

Thanks.

Avrohom

[Dan Ebberts]

The seed value of SeedRandom() just sets the starting point for the sequence of random numbers that get generated in the expression. You can stick any number you want in there to get different results. index is just the layer number (the index of the top layer is 1, etc.) and it’s just a convenient thing to use as a seed because it’s different for each layer. However, as you’ve seen, using the same seed for each layer generates different results for each layer anyway.

Dan

[Tom Granberg]

Is there a way to force the random numbers to certain increments?
Let’s say, always pick numbers that are 10 apart.
So you end up with position changes that looks random but in a pre-defined grid increments?

Thanks.

[Dan Ebberts]

Sure – something like this should work (not tested):

numberOfXPositions = 40;
numberOfYPositions = 30;
disctanceApart = 10;
x = Math.floor(random(numberOfXPositions))*distanceApart;
y = Math.floor(random(numberOfYPositions))*distanceApart;
[x,y]