Need to make your scene look cold? Check out these tips for creating realistic cold-weather breath in After Effects.
Images via Shutterstock
Despite a steady onslaught of major technical VFX innovations, it remains a massive challenge to animate cold-weather breath digitally. A great example of this truth is found in the following clip from The Social Network.
Regarding the effect, David Fincher had a bit to say:
The breath in this is faked. Not that it wasn’t ridiculously cold anyway, but we did not have the humidity that it required to have people’s breath be visible, and I just felt to ask people to stand out in this kind of cold weather and not see the breath was unfair. — David Fincher, via Slate
Creating a vapor effect is admittedly very difficult. People are very quick to see vapor flaws in films. This is probably because we see a lot of different types of vapors on a day-to-day basis. So, to help overcome the struggles associated with the need to create and animate cold-weather breath, we’ve put together a few tips to keep in mind as you move forward.
Tips for Creating Realistic Cold Breath
1. Have It Start 2-3 Inches Beyond Your Subject
Most default particle generators have constant opacity or slow fades over time. However, cold breath vapor works a little bit differently. In cold weather, breath is usually invisible for 2-3 inches beyond the mouth of your subject. Because of this, you’ll want to set your opacity map on your particles to form a curve where the particles will fade in over time instead of appearing all at once.
Another common mistake when working with cold breath is to make all of the fog a consistent shade of light grey. However, in real life, breath doesn’t stay constant in color or opacity. There will be splotches of differing amounts of opacity, leading to a highly texturized and random look.
3. Color for Light
Another mistake people make when animating cold breath is to make the vapor color white. In some instances, this is a completely appropriate way to approach vapor — but in most cases, breath vapor takes on the color of the light surrounding your subject. The best thing you can do when trying to create a realistic breath vapor is simply look for the color of the backlight on your subject. A backlight is typically the light source that gives the color to your subject’s color.
4. Add Some Wind
Breath, like all vapors, is easily affected by wind. So if you’re working on cold-breath replacement, you’ll most definitely see some sort of distortion by wind. When working with breath vapors, you should add in an additional wind parameter to give your breath a second level of believability. Plugins like Trapcode Particular allow you to put in an additional wind parameter to make your wind look more legit.
5. Secondary Swirls Add Realism
In addition to wind, vapors also have a secondary swirl that adds to their believability. Vapors don’t simply push away from a single point — they spin and rotate almost randomly throughout the air. You can create this secondary action pretty easily in After Effects by adding a keyframed liquify effect or turbulent displace effect.
6. Cold Breath Is Sporadic
Cold breath vapor is never consistent. One breath may be very ‘vaporous’ and visible and the next might not be at all. I suggest using a wiggle expression on your particle generator.
7. Cold Doesn’t Puff, It Wisps
Cold breath isn’t made of out-of-focus orbs. Instead, a cold breath puff is typically comprised of fractal-like wisps. In fact, cold-weather breath wisps look a lot like cirrus clouds. In most particle-generation software, you can import cirrus cloud stock photos to be used as the particle-generator source.
8. Less Breath Is More
One common mistake made among indie artists working on cold-breath simulations: adding too much of it. Breath vapors naturally draw a lot of attention on screen, so it’s best to keep the breath to a minimum.
Tutorial: Creating Cold Breath
Created By: Video Copilot
In this tutorial created by Andrew Kramer of Video Copilot, we take a look at how to use Trapcode Particular to create a realistic cold-weather breath effect in After Effects.