PDA

View Full Version : can anyone show me how to do this


bigmike2006
03-19-2006, 05:49 PM
I'm pretty new to After Effects and I'm trying to learn how to make this specific kind of animation.

I have a $100 bill that rotates around from front to back and then to front again.

I want to make a kind of transition, of a lot of these bills, hundreds of them, falling from off screen at the top to the bottom.

How would I make these bills fall in such mass numbers? The idea is that they would all be in different spots and fall slightly differently.

Is there a way to randomly generate hundreds of copies of the same object and control their position? Individually keyframing them is the only way I know how right now, and it's time consuming and tedious to say the least. Is there a plugin or expression I could use?

Thanks for your help.

DLangley
03-20-2006, 02:37 AM
Expressions would probably be your best bet. The best site I know of for learning expressions is: http://www.motionscript.com

I'm sure there are folks with more expertise than me, but the set up for creating a trail of objects is actually an example printed in the AE help files. Just do a search for example expressions. It works like this

Create a comp with a bill moving down. Duplicate your first bill layer. With two instances of the bill layer now in the timeline, go to the second instance and delete any position keyframes. Alt/Opt click on the stopwatch for the position property and add the followingg expression:

thisComp.layer(thisLayer, -1).position.valueAtTime(time - .5)

What this does is tells layer 2 to take its position value from layer 1 but delay it by half a second. You could then duplicate layer 2 multiple times. Now all the layers will follow the one before it, each delayed half a second from its predecessor. I recommend you set the first layer to start just off screen and end its position far enough below the bottom for all layers to exit the screen. You may have to fiddle with the valueAtTime parameter to space out your bills properly.

You can then take that comp and nest it into another comp. Turn on the 3D layer. Go to Window, Cubic Distribution Lite. Now, I am using 6.5 pro which comes with Cubic Distribution Lite. If you don't have it obviously this won't work, but you can purchase it from Digital Anarchy. Anyway, you will get a dialouge box where you can specify the number of times to repeat the layer and the distance in x,y,z space you want for distribution.

This should get you close to what you are looking for. You add other expressions to simplify the movement of the initial bill, like loopOut, and others. But this is the easiest way I can think of. I hope this helps.

2a03
03-20-2006, 09:59 AM
Just buy Particular and use this file...

http://www.trapcode-people.net/filedetails.php?fileid=65

m|3
03-20-2006, 03:40 PM
I'd suggest you read up on Particle Playground in AE. I've done a similar transition effect with balloons using this.

beenyweenies
03-20-2006, 08:18 PM
I'm pretty new to After Effects and I'm trying to learn how to make this specific kind of animation.

I have a $100 bill that rotates around from front to back and then to front again.

I want to make a kind of transition, of a lot of these bills, hundreds of them, falling from off screen at the top to the bottom.

How would I make these bills fall in such mass numbers? The idea is that they would all be in different spots and fall slightly differently.

Is there a way to randomly generate hundreds of copies of the same object and control their position? Individually keyframing them is the only way I know how right now, and it's time consuming and tedious to say the least. Is there a plugin or expression I could use?

Thanks for your help.

All the suggestions above are great ideas, but the problem is your object is double-sided so many of these might not work as expected. I don't know how you've set up your two sides, but I would assume your front and back are two seperate layers. I would suggest sandwiching them together (both as 3d layers with one flipped), create a Null, center it with your front/back bills and parent both layers to the null. Apply any expressions or animations to the null instead of the layers to keep your front/back relationship.

Because you need this front/back arrangement, I don't think particular or particle playground will work, since they use one single-sided layer as the sprite. Your best hope (again this is just my opinion) is in expressions applied to the Null of this front/back/Null arrangement, and the set of three (front/back/null) duplicated for every bill you need on screen.
Try applying the following script to the Position property of the Null that carries your front/back layers. Adjust the "gravity" for speed and "ew" for the width of this fake emitter (should expand beyond edges of your frame). You will also need to create a spare Null that sits where you want the bills to emit from, basically just above your comp window, and name it "Null 1":

g=175; //gravity
wdir=0; //wind direction (0 = from left)
ew=800; //emitter width

birth=effect("life").param("Point")[0];
life=effect("life").param("Point")[1];
seed_random(birth,true);
origin=this_comp.layer("Null 1").position.value_at_time(birth) + [random(-ew/2,ew/2),0,0];
w=random(-50,50);
if(life==0){
origin
}else{
age=time-birth;
delta_w=w*age;
delta_g=g*age*age/2;
wa=degrees_to_radians(wdir);
origin + [delta_w*Math.cos(wa),0,delta_w*Math.sin(wa)] + [0,delta_g,0]
}

CGTalk Moderation
03-20-2006, 08:18 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.