Constructing a Planet in Adobe After Effects 6.5
Bryan Preston, Office of Public Outreach
Adobe After Effects is generally thought of as a motion graphics
or title creation program. But one of After Effects' more unheralded
features is its ability to support the creation of true animations
and special effects, the kind you can use to bring a little extra
pop to your planetarium shows and presentations. For instance, though
After Effects is a 2-dimensional animation program (meaning you
can't build true 3D models in 3D space), you can use it to make
some very 3-dimensional looking animations, and it does have a 3D
camera with 3D lighting built right in. This tutorial will show
you how to build a planet using nothing more than flat 2-dimensional
textures and a little bit of After Effects' deep capabilities.
First, we need the textures, and NASA has helpfully
posted them on the web. You'll find them and much more at NASA's
Observatory web site, which has earth textures based on the
data from a couple of NASA's earth science satellites. Since they're
NASA data, they're in the public domain. You can use them as much
as you want without having to pay royalties (you already paid the
“royalty” on April 15th ). Once you're on the Earth Observatory's
page, scroll to the bottom and download two textures—the daytime
earth texture with clouds and the night lights texture. Make sure
to get textures of the same resolution, for our purposes the ones
that are 2048 pixels by 1024 pixels will do. After Effects will
accept imagery of any size and will render to any size (from tiny
web movies to DVD's to IMAX and everything in between), but you
want to make sure in this case to get two texture images of equal
resolution. We're going to make a planet out of them, and that's
easier to do if they are a matching pair.
Once you've downloaded the images, open up After Effects. You'll
need to import the two textures, and to do that go to File/Import/File,
navigate to the images and click OK. Note that they have shown up
in your Project window, and if you click on them individually After
Effects will pop up a little thumbnail image and tell you a little
about them—their resolution, etc. Now you need to make a Composition,
which is where all the action in After Effects takes place. To make
a new Composition, go to Composition/New Composition
in your menu, or just hit Control+N. You'll get
a dialogue that lets you set the parameters for the Comp—set it
to NTSC D1 720x486, .9 pixel aspect ratio, 29.97 frames per second,
length of 10 seconds. You're working in TV resolution with a TV
frame rate, but After Effects can also work in film resolutions
and frame rates.
You have a Comp now, so the next thing you need to do is start
building your planet. With one of After Effects’ built-in
plug-ins, it’s surprisingly easy. First, click and drag the
daytime texture into your Timeline. Note that it
has shown up in your Timeline as well as in your Comp window, and
that it’s flat. It looks nice, but not very planet-like.
To make it look like a planet, we need to wrap it around a sphere.
With the texture selected, go to Effects/Perspective/CC
When you click on that effect, two things happen. First, in your
Comp window the flat texture gets wrapped around a sphere that is
lit from the left. Second, your Effects Window
pops up and shows that you’ve applied the CC Sphere effect,
and shows you that you have some parameters you can adjust. In the
Effects Window, as well as in the Timeline if you twirl down the
Effects twirly-gig on your texture layer, you can mess with the
effect’s lighting and camera controls. You can also make the
planet rotate, make it larger or smaller in the screen and tell
it whether it should render only the sphere’s exterior, interior,
or both, and with or without internal shadows.
For our purposes, resist the temptation to fiddle with all those
controls and focus on the Light parameter. Twirl it down and you’ll
see that by default After Effects has lit the sphere from –85
degrees. I don’t know why that’s the default. It’s
sort of like the default red text that After Effects generates when
you apply that effect—it’s most likely there to force
you to change it. Who uses red text as a default style? Who lights
their planets from –85 degrees?
We want our planet lit from a more pleasing and dramatic angle,
so change the Light Direction from –85 to
+54. There are two ways to do that. One, just click in the Light
Direction wheel until you get to +54. Two, click on the –85
itself and type in 54. Either way will give you the same result,
which is to move the light from one side of the Earth to the other.
To make the scene even more pleasing, we should change the height
of the light, from its default 40 to 13. Turn off the Ambient light
by clicking on its default setting and typing in 0. If you’ve
done it correctly, your planet should now look like this (note that
the planet appears slightly elliptical here because we're displaying
a video image on a computer display, so pixels that are supposed
to be non-square are shown as square):
Now let’s make it rotate. First, in the Effects Window twirl
down the Rotation parameter. You’ll see three
wheels, for X, Y and Z. Three dimensions in a 2-dimensional program!
You could mess with all three dimensions and create a dizzy earth,
but you don’t need to for this tutorial. We’ll only
need to rotate in the Y-axis, so just click on the little stopwatch
next to the Y-axis wheel. Go to your Timeline and with the layer
selected, and hit the U key. You’ll see a little diamond has
appeared in the Timeline. That’s a keyframe, and you created
it when you hit the stopwatch. Keyframes are what you use to make
things go in After Effects. Hitting the U key exposes all keyframes
set on a given layer—the more keyframes you set to create
effects, the handier the U key becomes. To make our planet rotate,
we’ll need to set another keyframe at the end of the Comp,
so hit End and your time marker will move from
the start of the Timeline to the end. Above the Y-axis wheel there
are a couple of numbers, 0 and +0.0. The first 0 denotes the number
of rotations, the second set denotes degrees. We just want to make
the planet rotate twice, so click on the first zero and type in
2. If you click and drag the time marker in the Timeline, you’ll
see that your planet is rotating. You can hit 0 on the number pad
on your keyboard, and you’ll start building a RAM preview
of your animation, which will show rotation on your planet.
But a rotating planet without some nod to the night is kind of boring.
So first hit Home, then click and drag your second texture image
from the Project Window into the Timeline, and make sure to place
it below the texture that you’ve already turned into a sphere.
You’ll see the night texture in the Comp Window, but flat.
Apply the CC Sphere effect to it the way you applied it to the first
texture, and your texture will disappear. It’s actually behind
the first texture, and by clicking on and off the little eyeball
icon in the Timeline next to the first texture, you can see that
your night lights texture is there, is a sphere and is lit from
the left. The problem is, you can’t see the night texture
unless you turn off the day texture, and that doesn’t help
sell the sphere as having a night side rotating into day. We need
to see the night texture transition gradually from darkness into
Before doing that, though, we need to make it rotate. Do that the
way we did the first, making sure that your first keyframe is at
the Comp’s start and the second keyframe is at the end, and
that you’re rotating the sphere twice. Its speed should match
pixel for pixel with the first sphere, otherwise the effect won’t
So now we have two rotating spheres, the day side covering up the
night side. We need to make the transition from night to day, and
the way to do that is with a luma matte. Matte
channels tell a layer what parts are to be seen and what parts are
to be invisible, and we can use one here to make the lit part of
the dayside earth visible while making its dark side invisible,
which will reveal the night side with lights.
To build the matte, we’re going to build a sphere out of nothing.
Go to Layer/New/Solid, and click. In the dialogue
box that appears, make the Solid white and give it a size of 2048x1024
to match your texture layers, and change its pixels from .9 to Square.
Use CC Sphere to turn this layer into a sphere, and line it up with
the daytime sphere so that it covers it and their edges meet precisely.
Light it from +54 degrees.
This new sphere is your top layer, and if you click on the Switches/Modes
box at the bottom center of your Timeline, you'll notice that the
settings change. In the column called TrkMat,
set the daytime layer's matte to Luma Matte “White Solid 1” (or
whatever you named the solid you created in the previous steps).
Voila! You can now see the dayside of the earth on the right and
the night side toward the left. Scroll across the Timeline and you’ll
see that it’s animated and the night side is rotating smoothly
into day. To change the transition region’s lighting, adjust
the light on the White Solid’s CC Sphere Effect. If you want
to make the night side a little more visible, increase its Ambient
light from 10 to 50 or more.
Using this effect, you can create space scenes that include camera
moves, sunrises—just about anything. You can project your
rendered animation onto your dome or screen, surround it with slides
or other graphics, and add a little bit of realism to your shows.