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Particular - shape as emitter?

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Bartosz GrzegolskiParticular - shape as emitter?
by on May 24, 2011 at 2:24:03 am

Hi everyone,

so I'm trying to make clothes disappear off of somebody's body while they're standing. Made two videos with and without clothes and am using masks to get the effect of the clothes slowly being "eaten" away beginning from a couple of different spots. Now, I want to use particular to make this "eating" effect more like "dissolve" with particles having a small negative value for gravity. It looks great but it would look even better if the mask path that reveals the unclothed body was the emitter. Starting with the right sleeve I converted the mask into a shape (and onto a shape layer) and editted it a bit so all I have now is this animated curvy line that should emit the particles. How do I do this?

btw, I tried precomposing it and using particular layer emitter option but all I see is a couple of particles around the shape no matter what value I change. I also read a couple of posts here that seem to be related but none of them helped.

I'm using AE CS5 and Particular 2.

I hope you can help me :)
Thanks a bunch.


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Kevin CampRe: Particular - shape as emitter?
by on May 24, 2011 at 5:02:00 pm

i'm not sure i understand exactly what you have and exactly what your after -- i do understand the basic idea of what you are going for...

take a look at this tutorial and see if it is heading in the direction that you want:

http://library.creativecow.net/articles/lee_james/particle_build_up.php

it shows how to use a animated layer as an emitter to make a layer 'disintegrate'.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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Bart GreguskiRe: Particular - shape as emitter?
by on May 24, 2011 at 11:38:35 pm

Thanks a lot Kevin, that's exactly what I needed. The way he tackles the problem is different from mine but does exactly what I want.

Just out of curiosity, if I tried doing it my way, can I make an animated shape, like a line, emit particles? Imagine the balloon from the tutorial but with the mask path used for hiding the balloon not being a straight line but a wiggly one. I take that wiggly mask path and paste it into a shape layer as a shape path. Then I trim the path so I can only see that part which is the border line between the balloon intact and where particles begin. Now, I want to make this part of the trimmed shape path emit particles and it doesn't matter to me that the particles won't look like they are part of the balloon. Is something like that possible?

Thanks for help Kevin. Much appreciated :)


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Kevin CampRe: Particular - shape as emitter?
by on May 25, 2011 at 3:44:37 pm

[Bart Greguski] "can I make an animated shape, like a line, emit particles?"

yep... the line would need to be precomped, but then you could set that as the emitter in particular (make the precomp 3d first).

if you wanted the particles to look like the clothing that is disappearing, you would add the clothing to the precomp and use the line as a track matte (or similar), then in the main comp, you could set particular to use the layer emitter for rgb color of the particles.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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Bart GreguskiRe: Particular - shape as emitter?
by on May 26, 2011 at 2:29:54 am

wow, I have just tried what you suggested and it works wonders :) that's what I'll use in my project.

Many thanks!!


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Bart GreguskiRe: Particular - shape as emitter?
by on May 26, 2011 at 2:27:03 pm

I precomposed the line, made it 3d, and set it as the emitter in particular but why do I have to bump up the particle count really high to be able to see not that many particles? I was just wondering what's the technical explanation for this. Why can't it emit particles the same way the original emitter does where the amount of particles you set it to is what you see on the screen?

Thanks


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Kevin CampRe: Particular - shape as emitter?
by on May 26, 2011 at 10:12:41 pm

i think its because it looks at the size of the emitter layer (probably full screen for a precomp) and calculates the number particles over that area, but the only renders/emits those that would be 'born' where the alpha is opaque.

so, if only 10% of the emitter layer is opaque, then only about 10% of the possible particles will be emitted.

you can try making the emitter precomp smaller -- just large enough for what it needs to be -- but taht can often be hard than it would seem... it just depends on the comp.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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Bart GreguskiRe: Particular - shape as emitter?
by on May 27, 2011 at 1:56:38 am

Thanks. I will try that :)


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Bart GreguskiRe: Particular - shape as emitter?
by on Jul 10, 2011 at 6:01:52 pm

Thanks again for the help and here's the video I was able to make with your help.







Cheers.


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