Random Scale Up (for multiple objects)

[Simon Roberts]

oh yeah…

effect(“life”).param(“Point”)[1]

relates the effect “point control” that has been renamed “Life” that has it’s own expression (that generate two numbers… x=0 and y=between 1.5 & 3) that also powers some other expressions as well as scale.

thanks… any help would be fantastic!

sorry if that’s not very clear… i’m quite new to expressions

[Darby Edelen]

[Simon Roberts] “max_scale=21; //maximum scale
smax=5; //scale ramp-up time
smin=2;
s=random(smin, smax);

life=effect(“life”).param(“Point”)[1];
age=time-effect(“life”).param(“Point”)[0]; //age=time-birth
if (age
x=(age/s)*max_scale;
[x,x,100]
}else{
[max_scale,max_scale,max_scale]
} “

If that is exactly the way your code is entered, your if() statement isn’t doing anything. Also, your random ‘s’ value is re-evaluating at every frame, so you may want to seed a ‘timeless’ random.

Try this instead:


max_scale=21; //maximum scale
smax=5; //scale ramp-up time
smin=2;
seedRandom(index, true);
s=random(smin,smax);

life=effect("life").param("Point")[1];
age=time-effect("life").param("Point")[0]; //age=time-birth

x = linear(age, 0, s, 0, max_scale); //If 'age' is ever greater than or equal to 's' then 'max_scale' will be returned thanks to the magic of the linear() function!
[x,x,x];


Emphasis is added where I changed your code.

Darby Edelen
Lead Designer
Left Coast Digital
Santa Cruz, CA

[Simon Roberts]

thats brilliant… it works just as i wanted. it’s funny how you can try and work stuff out for hours and then someone who knows about these things comes along and can write the code in a few seconds.

thanks again