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Fog in AE?

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Anne Lawant
Fog in AE?
on Dec 8, 2009 at 1:55:51 pm

I'm looking for a way to make digital fog. I heard that there was a tutorial on doing it on creative cow, but I can't find it. I also heard that using Trapcode would be a good way to do it, but I'm talking more about the thick fog, the one that makes visibility go down, sorta like this:

-Anne Lawant

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Michael Szalapski
Re: Fog in AE?
on Dec 8, 2009 at 2:29:27 pm

AE has a built in 3d fog plug-in but it works with a 3d depth matte rendered out from your 3d program. It looks good, but it's not going to work with just your AE comp (unfortunately).

You could paint a depth matte, but that's probably more work than you'd want to do.

Buena Depth Cue does have a fog plug-in that works with your AE layers. I haven't used it myself, but I've heard it's decent.

You can use multiple layers of turbulent noise, fractal noise, or Photoshop-created layers to simulate fog.

And there are several ways you could use Particular to fake it as well.

Try a search for fog on Adobe's community help, you're likely to come up with something useful.

- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.

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Joseph W. Bourke
Re: Fog in AE?
on Dec 8, 2009 at 2:49:11 pm

Hi Anne -

From your reference shot, it looks as if you're trying to create mist - although I'm being a bit nit-picky here. I think of fog as the rolling, moving, cloud-like stuff, and mist as a light screen that's almost solid (no cloud shapes), but still translucent.

At any rate, there are a couple of ways to go - one is to just use a couple of Fractal Noise layers, and set the complexity way down, if you want the misty look. You can stretch it on the Y-axis to give it the layered look, and also make a couple of layers so that there is a foreground and a middle ground, with slightly different settings.

The second way to go is with a 3D effect. The only way I know to activate AE's 3D effects is to bring in an RPF or RLA layer from a 3D package, such as 3D Studio Max. You can import your layers with Camera, Alpha, and Z-depth. Then once you import to AE, you've got access to the 3D filters. There are many other setting available to the RLA or RPF file, and you can actually convert a 3D camera in AE and it will create keyframes. Hope this helps.

Joe Bourke
Creative Director / Multimedia Specialist
B&S Exhibits and Multimedia

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Kevin Camp
Re: Fog in AE?
on Dec 8, 2009 at 4:32:15 pm

i'll go the more fake route...

first, i'll assume that you have a 3d scene set up in ae, with different 3d layers placed at various depths, and have a 3d camera.

since the effect of fog/mist is having objects that are further away blend into the fog, you could use an expression to have layers that are further away from the camera blend away. dan ebbert's has a similar expression for creating light falloff, and we can tweak that slightly to create a fog falloff effect.

first you'll need to add a couple effects. first add the fill effect and set the color to the a foggy background color, like light gray -- i suppose to pull this off, you should also have a 2d solid behind your 3d layers that is the same light gray color.... the add the cc composite effect after that to composite the original image over the 'fill' color.

add this tweaked expression to the opacity property of the cc composite effect:

decay = .001;
noFalloff = 2000;

L = thisComp.layer("Camera 1");

d = length(L.transform.position,transform.position);
if (d < noFalloff){
value/Math.exp((d - noFalloff)*decay);

you'll need to modify the decay and noFalloff values to suit your scene, but if you change the camera position or the layer's position, the layer should 'fade' into the fog.

if this works for you, then you can select those effects and copy/paste them onto your other layers.

Kevin Camp
Senior Designer

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