Randomizing Keyframe Destination?

[Filip Vandueren]

Hi David,

[David Scorca] “Maybe something like position.valueattime(10)[1] = random()? Will this then translate into the motion path?”

You’re thinking backwards where expressions are concerned. You can’t change the values in a keyframe or in a layer from within an expression. (you can do this with a script which is something else)

You would have to apply an expression to position that yields the correct result for every frame where it is calculated. Something like this:


seedRandom(index,true); // seeds the random number to 1 unique random value

start_pos=[0,240];
end_pos=[600, random(0,480) ];

anim=ease(time,0,10,start_pos, end_pos);

// the difference between the wiggled position and the original position=just the jiggle
wigg=wiggle(1,50) - value;

anim+wigg;


incidentally, using a seedRandom makes sure you get a unique wiggle too.

[David Michael]

Very interesting. I understand basically how you’ve set that up, and this is certainly going to make my world a hell of a lot easier. I’m going to take that code, play with it as soon as I get home and look up all the functions to make sure I understand them inside and out. Basically, what I see is that there are only a few commands ease(), wiggle(), random(), and seedRandom(). And most of the lines are definitions of the arrays and ease() is really the driving force behind this operation, as it is going to draw the line over the 10 seconds, and it’s got the wiggle built in. Before reading your response I didn’t realize variables could be arrays and that will be endlessly useful. Thanks again for your help! If what I end up animating is worthwhile looking at all I’ll make sure to post up a link.

[Filip Vandueren]

Okay,

also take a look at the other interpolation methods:
linear() and easeIn() and easeOut()