copy stamping, rand() and probability

[Spyrogif]

hi every one, i've a question about the rand() expression fonction.

I use it in a classic copy stamping context.

my "template" is a simple grid and "my primitive to copy" input is plug to a switch node who have many differents input (here 12).

the expressions i used to control switch stamping is :

int(fit(rand($PT),0,1,0,12))

a 10*10 points grid gives me this.

the result is pretty good to me. all the switch input are present. Every inputs haves between 6% and 12 % chance to be present. it's exactly what i need.

now

a 4*4 points grid gives me this.

here come my problem.

i'm agree with the fact that some input appears more than one time. But why some inputs are so present (here the a11 input).

Here 6 input are not used and the a11 input made 31% of the all thing.

Is there any math\expression genius who can help me to get a more "spread" result when my template have a low point count.

thanks a lot for your help.

[mightcouldb1]

I think it would be the easiest to just change your seed value.

rand($PT * 123)

Then you can change the number around until you are happy.

Hope that helps,

Jason

[Spyrogif]

I think it would be the easiest to just change your seed value.

rand($PT * 123)

Then you can change the number around until you are happy.

Hope that helps,

Jason

you right, i try a lot of differents seed value and one give me the result i need.

I was thinking to something more "cartesian" but i'm completly happy with this.

thanks for tips and quick reply .

[graham]

An alternative thing you could do, if you just want randomization and don't really care about it being a purely randomized distribution, is you can just use a Sort SOP to randomize the point order and then just stamp $PT % (number of choices).

random_grid.hip

[Spyrogif]

An alternative thing you could do, if you just want randomization and don't really care about it being a purely randomized distribution, is you can just use a Sort SOP to randomize the point order and then just stamp $PT % (number of choices).

.

thanks graham, your way is just perfect and more flexible for my asset. I think i will use $PT % a lot of time now.