Use of After Effects Fractal Noise for Astronomy Videos

Published on 6 November, 2024

Sam Chatterjee

Introduction

The universe is indebted to the Adobe After Effects Fractal Noise. Err….I am not on high.

What I mean is, most of the Documentaries and videos on Astronomy are made in After Effects and with an extensive use of fractal noise. And to know or understand our Universe, you have to resort to Astronomy.

In a previous article I discussed how to create starry background in a space scene and a spiral galaxy touching a bit of fractal noise in the process. In this piece, I would deal with more applications of fractal noise for making other extra terrestrial objects, especially the stars.

The fire and flames of the stars that we see in the astronomy videos or documentaries are due to their nuclear fusions which add the atoms of lighter elements to yield to the atoms of heavier elements. But, this process releases enormous amount of energy in the form of heat and light what we see as the radiations emitted by the star.

The sun, a mid sized star and the only one in our solar system, loses as much as 4.5 million tons of mass every second due to its nuclear fusion. But that’s no big deal. It will still radiate for a few more billion years.

And let me now put down my physics student (6th grade) hat and turn to After Effects for creating such a star blazing with its nuclear fusion.

Let’s come straight to the point. Referring to After Effects CC 2022, let’s create one HD i.e 1920X1080 composition.

1. Multiple Layers added an After Effect Composition and Fractal Noise applied on them

I have added a few layers, 3 in fact. With Solid Color as Black, added fractal noise to all of them.
I have tweaked some of the settings and then added Time Expressions to the Evolution to make the noise animate over time. Let’s first see the parameter settings and then the animations.

Time Expression differ in values to make the different in animation more evident and the evolution out of phase.

You may play around different settings like Fractal type, Contrast, Brightness and others to strike a suitable one or somewhat close.

2. Color Corrections with an Adjustment Layer

Now that you have made the base, it’s time to add colors to these fractals for getting close to the star cores with nuclear fusions. I have used two different color correction effects for doing this. I have renamed the Adjustment Layer as the ‘Color Control’.

Lumetri Color
Curves

The reason why I used Lumetri Color before applying Curves is it helps you attain the color temperature much better than with the help of Curves alone.

The color I attained in the header image of this article was done using Photoshop’s curves too, along with AE’s curves. This made me realize Photoshop’s Curves is much more advanced compared to the After Effects’. And that’s obvious, as Photoshop is an image based program.

Let’s examine one by one.

2.1 Use Lumetri Color for Color Correction of the Layers with Fractal Noise

Temperature 57.5
Tint 7.8
Exposure 1.0
Contrast 25

If you compare this with the color in GIF animation above, you could see that there is a difference evident in terms of contrast. The highlights and shadows are now more pronounced. The change in hue at this stage will be much more easier to get close to what we want.

Needless to say, you can play around as long as you want to get to yours one. The idea is to watch out for the images or videos online get to as close as possible. Let’s now look for the Curves.

2.2 Apply Curves to change and refine the Color/ Hue

Since the color or hue of extremely hot zone is high with red and warm tone, there would an upward bulge in the red curve in the middle area, while a downward curve in the blue curve in similar region.

You can even think of adding keyframes to the Curves, if there is a camera animation, from warm tone to a warmer as the camera move closer.

2.3 Star Core after Color Correction on the layers with After Effects Fractal Noise

Nuclear fusion is very common in the videos on Astronomy, especially while showing a star core.

Clearly, After Effects Fractal Noise plays a functional role in simulating such scenes. Let’s now do a little bit of compositing.

3. Compositing for the Space Scenes – the Star Flames or Flairs

Let’s first have a close look of an image of the Sun. It’s released by the NASA and can be found in a Wiki Page.

If you watch out closely there are flames and flairs around the Sun and for that matter every star. The flames rise up quite a few million kilometers from its surface.

In reality, these are not fire or flames in the sense we call something fire or flame here on the earth.

The ‘flames’ or the towering structures leaving its surface is called prominence. It’s the vast region of solar plasma made up of Hydrogen and Helium gas and trapped in highly unstable electromagnetic lines of force or fields. These lines of force keep on changing and can last from hours to weeks or even months.

U mm…let me again keep aside my love for physics and focus on compositing for star surface with the help of After Effects Fractal Noise that we’re dealing with.

3.1 Apply CC Sphere to make the layer (Pre-comp) with Fractal noise look like a Star

Needless to mention that I have made a precomp with the multiple layers that I applied fractal noise on. Now let’s apply CC Sphere on that precomp.

I have changed a few settings and marked them. Do take a note and play around if you want to make it otherwise.

3.2 Create a Texture Map for Flares from the Star Surface – First Add Fractal Noise

A few tweaks I have made to the parameters, that I have marked. Besides, I have changed the Offset Turbulence to 960, -850 and the Complexity to 10 that are not marked here.

Also, I have added a time expression to Evolution i.e time*50.

3.3 Add Turbulence Displace to bring a ‘Flare texture’

Pretty simple. I have changed the Offset Y Coordinate to 500 and added a time expression to the Evolution i.e. time*80.

3.4 Add Unsharp Mask to sharpen the ‘Flares’

3.5 Apply Distort > Polar Coordinates to Make the Texture Map Circular

Now this is the look of the Map that we would be using for the Star’s outer flares. But for that we have to create a couple of Masks.

4. Mask In and Out the Flare Texture Map to Create Star Flares

This Flare Texture Map requires masking and color correction in the background of the Star that we created. Clearly, this texture has a sim vertically upward that we have to get rid of. One way is to clone this map and rotate in different angles. Let’s do that and Mask in and Out.

Let’s see the image below and analyze.

4.1 Duplicate the Flare Texture and Rotate in different angles

Clearly, the sim has shifted. It’s still visible in this image, but won’t be so while animating. I have made them + and – 90 degrees. But try differently, may be 113 and 286 or something you like them to be.

4.2 Create Two Concentric Masks punching in a hole at the center to ‘hold the Star’

The outer one or Mask 1 to be Added, while the inner one or Mask 2 to be subtracted. The Feather amount could be same, but the expansion would naturally be different for two different diameters.

4.3 Add Brightness and Contrast to make the Flares more pronounced

I have assigned 40 as the value of Brightness, keeping contrast at 0. Let’s not forget to check on Use Legacy (Supports HDR).

5. Final phase – Add Glow layers over and beneath the ‘Fractal Noise Fusion’ layer

Quite a few things took place here. I have added two Solid layers (white), renamed as Glow and Glow2. One over the ‘Fractal Noise_Fusion’ precomp and another beneath.

5.1 The layer ‘Glow 2’ over the ‘Fractal Noise_Fusion’ precomp and its breakdowns

Just like before, I have created a couple of masks one with ‘Add’ mode while the other with ‘Subtract’ Mode. The Feather and Expansions values for both ‘Mask 1’ and ‘Mask 2’ can be seen in the screenshot. After masking in and out, you have to add some color or tint.

I have applied Fill over this Glow layer to change the hue. With the picker, you sample star surface and pick the warm tone to

conform. This brings a warm tone to the Flare. You can use other Color Correction effects to reach out to what you aim at achieving.

5.2 The glow layer below the ‘Fractal Noise_Fusion’ precomp and its make

This time I have applied Curve to manipulate the color. Note that the halo behind the star may be cooler in tone than the flares rising up from the surface itself.

Conclusion

After Effects fractal noise has tons of applications, in case of making Astronomy videos or the documentaries. I have just scratched the surface to simulate the nuclear fusions that are common to every Star.

I haven’t touched upon the Camera movement and their rendition in 3D space. That’s no big deal I guess, since this is a 2.5D program and not 3D. You have limited options in terms of camera animation.

Mostly the camera moves in Z space giving and impression of traveling to or away from the extra-terrestrial object.

Another thing I must point out. You may consider bigger comp size for using fractal noise and other texture maps than your final render. It offers a better room for camera movement in space.

I will come up with another piece on the space scenes with After Effects shortly. Till then, good bye.

Please don’t forget to share this piece if you find it useful.