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MaxLevelArt
Participating Frequently
April 30, 2019
Answered

Realistic Neon Flicker [noob request]

  • April 30, 2019
  • 1 reply
  • 12913 views

Hello!

I'm fairly new to After Effects and I'm using the most recent update [16.1.1 (build 4)]

I'm trying to create a neon light that begins inactive, then flickers with increasing frequency, until it becomes 100% active.

I could animate each key frame, but I know there has to be a more efficient method. I know I can use the wiggle expression, but I can't find a way to animate the parameters to achieve this effect. I tried using the Slider Control, but that didn't work because I couldn't figure out how to make the effect go from inactive, to increasingly active, to 100% active.

I've seen several tutorials, but none of them show a way to do what I'm picturing. I considered clipping the layer and pasting an "off" version at the beginning, and an "on" version at the end, but I would genuinely love to learn and know if there's a way to accomplish my vision with a single layer.

Thank you for taking the time to read and respond.

This topic has been closed for replies.
Correct answer Rick Gerard

Bear in mind that neon is either on or off. It doesn't "fade" up and down, which is what all the various suggestions are doing.


If you want to get absolutely accurate about a neon animation there would be just a couple of frames where the start and end of the tube would have a different intensity and color as the AC voltage is applied.  Neon light flickers all the time at the same frequency as the current. Try shooting a neon sigh at 100 fps and see what you get. When designing a visual effect it is always a really good idea to look at some actual footage of the thing you want to create. There is lots of footage of neon tubes available.

My point is that a realistic startup always involves an arc pulsing at the start and end of the tube to get the ionized gas to light up. If the power supply is tired the arc will start and stop causing the light to flicker on and off as the arc starts and stops, but there is no difference in the intensity. The arc always makes noise, and the transformers handling the load almost always also make a little noise and that sound reinforces the visual effect of the startup flicker.

This video has a closeup of the electrode energizing the neon.

Unfortunately, the random time expression would not give you anything that actually looks like a neon tube flickering as it turns on. A similar approach to the expression I already posted would give you the on and off startup required to create a fairly realistic neon light startup. Modifying value1 and value2 to zero and 1, then multiplying the result by 100 would do the trick. Something like this:

If I wanted a one-second random startup for a neon tube without the other nuances that would sell the effect I might use this expression:

t = easeIn(random(time,5)/2,0,1);

Math.round(t)* 100

But the effect would be much more believable if you synced it to an audio effects track.

1 reply

Kyle Hamrick
Community Expert
Kyle HamrickCommunity Expert
Community Expert
May 1, 2019

There's definitely value in learning how to do things with expressions, but this example is short enough that keyframes are probably the best route.

M
MaxLevelArtAuthor
Participating Frequently
May 2, 2019

Thank you for taking the time to respond

That's fair, but I would really like to know how to do this for my own knowledge. I just learned about the random() expression, so I'm going to give that a try.

    R
    Community Expert
    Rick GerardCommunity Expert
    Community Expert
    May 11, 2019

    Yeah, I understand this function you've helped me create, but I'm already asking myself how I could make it terminate to zero after a given period of time. I know that I could just clip the layer (which is what I've done in my comp), but I'm still curious because I know that knowledge would come in handy some other way.

    I was pretty intimated at first, but I'm beginning to understand the basics after watching guides and tutorials on YouTube for a few hours. I will take your advice and look into the basic JavaScript math methods before doing anything else with AE.

    Cheers!


    the easiest thing to do is to split the layer where you want the light to turn off, remove the expression from the new layer and animate the property that is turning the light on and off. Don't waste an hour creating an expression when 1 or 2 keyframes will do the trick. If you plan on making money as a filmmaker you have to value every second of your time. I could modify the expression and test it. It would probably take me 20 or 30 minutes, or I could set the CTI to where I want the neon light to turn off, press Shift + Ctrl/Cmnd + d, then press uu to reveal all modified properties of the new neon layer, delete or turn off the expression and set the property that turns the light on and off to zero and I'd be done in less than a minute. 30 minutes, even for a newbie, is worth at least $35 so unless I had about a hundred of these layers to do in the next three weeks, working out an expression and saving an animation preset is a complete waste of money and time.

    On the other hand, every hour you spend studying techniques and methods when the author is a professional that has good workflow habits and creative approaches to solving problems will save you hundreds or even thousands of hours over a career. That study time can be worth tens of thousands of dollars per hour when you look at a career in the film making business. Please take the time to vet your trainers, make sure they know what they are talking about, and only spend time with tutorials and articles produced by professionals with good workflow habits. Unfortunately, more than half of the new tutorials and articles I see these days are presented by amateurs and they usually leave out critical information or propose inefficient or dead-end workflows. Bad habits are very hard to break so please, vet your trainers...

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