City Lights Effect in 2D Animation

[John Carrington]

maybe try using fractal noise as a track matte for the twinkle and adding a glow for the luminance

[Darby Edelen]

Where are your source files coming from? Video? Renders?

Your best option is to get a matte of the lights somehow and use it to add in additional light. How you get that matte will depend on what sources you have at your disposal.

Also, the lights themselves aren’t actually twinkling. It’s an atmospheric effect, so you don’t want to think of it as ‘lights twinkling’ so much as ‘little bits of atmospheric mumbo jumbo interfering with the lights.’ Lights that are farther away will be more affected by the mumbo jumbo 🙂

Fractal Noise isn’t necessarily a bad option for this, but you’d need very high frequency fractal noise animated with a fast evolution.

Would it be possible for you to provide a still image from a particularly difficult scene?

Darby Edelen

NVIDIA
Santa Clara, CA

[Patrick Algermissen]

I don’t have AE on the computer I’m using right now, so I can’t check this. However, here’s what I would try (similar to what John said):

For your stars, apply fractal noise to a solid.
Adjust the brightness & contrast settings in the fractal noise effect (and whatever other settings are necessary) until you get little white points over black.
Then, you can animate the evolution with an expression (time * someValue) to get the twinkle.
Apply glow to this for a starry look.

Hope this helps!

Patrick Algermissen
Poem Pictures, Inc.
http://www.PoemFilms.com

[Eric Ransdell]

Thanks to everyone for their advice. The source files are coming from Maya Renders output as .psd animation sequences or hand-drawn .psd still city backgrounds. I’ve been using AE for almost a year and don’t have a huge amount of experience with setting mattes. Tried John and Patrick’s suggestions using fractal noise/luma matte and it works, although the lights seem pretty dim even when AE’s glow or Trapcode’s starglow are applied. But I’m interested in figuring out how to pull a matte from the background itself and then fill the windows in with light. It’s the middle of the night here in China, so if you guys wouldn’t mind checking back tomorrow I’ll post again with links to a couple of our backgrounds and you can see what you think.

[Amir Sharafeh]

I’m not sure if I understand this right. Is this a still shot or a pic sequence? Is this also shot in daylight and you are trying to make it a night shot with lights flickering? Have you looked at possibilities in 32 bpc and then adding a glow, because the glow will punch up in 32 bpc. As far as your “window” comment you would have to most likely roto or mask out windows with a light feather and throw a regular glow on them so they will all look illuminated, but 32 bpc is your best bet as far as glowing frame(s). I just wanna understand everything that I asked and I’m sure with a picture it will become clearer. it seems like a fun seq. in AE. Put up your BG pix and make a comment so I can look once it’s posted.

[Darby Edelen]

[Eric Ransdell] “The source files are coming from Maya Renders output as .psd animation sequences or hand-drawn .psd still city backgrounds.”

I believe there should be a way to render another PSD sequence out of Maya with the lights pure white and everything else black. This may be more complicated in Maya than other packages, I’m not very familiar with Maya.

For hand-drawn PSD still backgrounds, try painting a black/white matte of the lights in Photoshop.

Your options in AE outside of the ones I just outlined are to create your matte by operating on the color channels of the image (perhaps using Calculations, Channel Mixer, Levels, Curves, Tint or others). If the lights are more/less saturated than the surrounding image you could even create a matte based on saturation if you re-map the RGB channels to HSL (Channels > Channel Combiner) and then use the Saturation (Green) channel. There are lots of options, the best one will depend on your footage… and even then there may not be a great one.

Darby Edelen

NVIDIA
Santa Clara, CA

[Eric Ransdell]

Here’s the link: https://flyfilms.com.cn/city_style_examples.php

One was screen-grabbed at third res, but otherwise they should give you a pretty good idea of the city we’re trying to light.