How would you go about recreating this effect within After Effects? (Maybe Particular?)

[Benji Trosch]

Hey Dave, thanks for the reply! Although I know a bit about Fractal Noise (enough to know how commonly it is used in After Effects; you’re so very right that it is very handy to be able to manipulate it for a variety of effects) I still don’t quite get how to go from basic fractal noise to a thick “rolling mist” that would operate as if it had fluid physics — or maybe it’s being faked with a wave warp?

I’ve tried looking for resources as far as turning Fractal Noise into smoke or fog, which is fairly simple, but I haven’t been able to find anything like that, if you know what I mean; it almost looks like a fluid rendered in 3D software.

[Steve Bentley]

Thats definitely stock footage of rolling fog/smoke (probably man made) And its not a custom element they shot for it because you can see the loop point and its not been handled very well (if it was custom it would have been closer to the right length). But based on the content and the noise that might even be back in the optical days.

I doubt you could get there with Particular without killing your machine with a billion particles.

Shooting is the best way to get that in short order – no render times and you keep wafting your smoke until you get what you want.
But for those without a camera and without Tubulence FD you can get there with fractal noise. The trick is the masking. If you make feathered masks that move and roll like you want the fog to (do this first before you get into working with the noise and then you can see the rough shapes moving about), then erode the edges of the masks with one set of moving noise and then pass another set of moving noise through these eroded masks. Make a few layers and composite them over each other – try not to use “screen” as that just ends up blooming everything to washed-out eventually. Also try different speeds of noise that drift and evolve with the direction of travel of the masks. Dont forget to tint your fog – it may seem like its white but its actually a tint of the background color.

Finally if you have it, Turbulence FD, Houdini and even Blender can get you there but there is a lot of non intuitive experimentation to “direct” that prima donna fog, and there can be long render times if you don’t want the noise to show (high sample rates).

[Benji Trosch]

Thanks Steve, that’s really in depth. And yes I can definitely see that loop point you’re talking about! It might be fun to try and film some of my own fog stock and composite it together with an obscene amount of masking. I’m thinking I could shoot at a higher frame rate and slow it in post for that slow marching feel. I’ll give it a shot!

My one concern is affecting scale: how to make it look like large hazy clouds rather than a tight shot of a cheap fog machine. The spaceship they add a few seconds in certainly helps, but everything will have to be just right. I guess we’ll see.

[Steve Bentley]

The better fog machines can use Mineral oil and you can tweek the nozzle to reduce particle size. Water’s surface tension is such that even when you generate small droplets, the minute you let them loose they glob together and you are back to a big droplet. One trick we have used in our water foggers is to add some camphor. This reduces the surface tension and may get you what you want.
Such is the nature of natural elements (fire too – trying to blow up a model is just as challenging due to flame sizes – the brain just knows something wrong).
If you use oil just remember to bag your camera and use a disposable UV filter to keep the mess out of the camera and use appropriate breathing protection.
You could also try dry ice (and water). Its the water particles you are seeing but because it wants to sink to the ground it tends to hold together a bit better and be more dense – but it does have a look.
The biggest issue with any of the above is the time between shots and the lighting. Once you start you build in this base fog level to the studio and then you have to wait for a while for it to dissipate or it shows in the shot.
Shoot wider than you think you will need but with a long lens.
The minute the fog leaves the frame you suddenly have an edge that limits where you can place the element. When shooting erupting fire we always shoot sideways so the fire leaps in the long direction of the frame and we tell the fire union that it can’t leave the frame..
And shoot at the highest true rez you can. This has the advantage of letting you use the footage anywhere in the comp and when you scale it down you are also scaling the water droplet size.
If you want to generate some footage of some fairly even fog moving about you can always use a turbulent displace to give it a few more “knots” once you pull it into AE. Then you can manually match the scale of the stuff one notices to the shot.
Shoot at the highest color depth you can. You can then crush levels in AE (work in a 16 or 32 bit comp and use 32 bit clean filters) and keep the fidelity but that crushing will bring out whisps and knots you didn’t even know were there.

I think you could get there with Turbulence FD ($$) or Blender (free – I’m not a blender guy but the sim engine looks eerily similar to TFD) but it can take a while to get the look you like and you will look up from the computer and the day is shot.