Exploration Of After Effects Spiral Filters
by Brian Maffitt, MAFF/x Inc. & Total AE
Chapter 1 - Introduction
Or "This guy again?"
Macintosh 2D and 3D animators have
long been able to map moving textures onto 3D objects. In most
3D programs you can map a texture onto anything and in a variety
of ways: spherical (i.e. mapping the world map from the Apple
Scrapbook onto a ball to make a globe), planar (i.e. mapping
a movie onto a TV screen), cylindrical (a label on a beer can),
cubic (holiday wrapping paper on a box). In After Effects you
can rotate a plane in 3D or, if you have the Final Effects filters
from MetaTools, you can map an animation onto a sphere or onto
Note: There's also
procedural mapping, in which the texture is based on a mathematic
algorithm, but we won't go into that here.
By mapping an animation onto an
object, moving elements appear to move across the object's surface.
There are limits to the kinds of animations you can do, however
current mapping techniques basically wrap an object with a texture
as if it were a decal. This means that somewhere on the object
a seam will appear. If you want something to travel around an
object, then it had better disappear on one side of the seam
in the same spot that it reappears on the other and it better
have the exact same size, speed, and rotation settings or it'll
Because of these limitations, mapping
an animated helix (think spiral staircase or DNA molecule) has
always been a tricky proposition, and has remained largely an
un-animated phenomenon on the Mac platform. With After Effects
3.0, however, you have very precise control and high-quality
sub-pixel rendering... and with a little grade school math (really!)
you can crank out a complicated helical animation in a jiffy.
a DNA molecule is a double-helix, which is also easy to animate,
as you will see.
Just to wet your appetite, click on this image:
Chapter 2 The FE Sphere
Or "There's nothing to sphere but spheres themselves"
When the European company UDAC
Multimedia introduced the Final Effects filters in 1995, it
ushered in a new age in Macintosh special effects. Half of the
filters were well worth the price of admission, the other half
One of the many gems of Final Effects
version 3.0 is the FE Sphere filter, which takes any After Effects
layer and makes a ball out of it. The tilt of the sphere can
be animated on any axis, lighting effects such as ambiance,
diffusion, roughness, etc. c an be set with great precision
and animated over time, the sphere can reflect its environment,
and it can create ray-traced internal shadows based on the transparency
of the layer. Not even ElectricImage can do that.
All of the fancy doodads are worth
exploring, but you can figure them out easily enough by just
playing with different settings. Rather than dwell on such basics,
this tutorial will concentrate on a few of the interesting,
less obvious abilities of this t ool.
First of all, it's important to
know that the filter is optimized to work on layers that have
a 2:1 aspect ratio that is, layers that are twice as wide as
they are tall. Things at the top and bottom of the sphere are
always going to get squished, but with a 2:1 ratio, things around
the equator will look nicely proportioned. You can apply the
filter to any layer of any proportion, but skinnier layers will
be stretched until they look fat, while wider layers will look
like the titles of a Cinemascope movie that have been compressed
to fit on a TV screen. Stick to 2:1 when possible.
When you apply the filter to a
layer, the extreme right and left edges will meet at the back
of the sphere.
Take a look at this
image (the checkerboard indicates transparency):
When the FE Sphere
filter is applied, it looks like this:
Adjust the z and
y rotation parameters, and you can get a clearer look at the
Every layer maps this way. It might
seem like this is restrictive, but once you understand how layers
interact with each other, there are a lot of possibilities.
So how do I make text "spiral"
around a sphere?
Chapter 3 The Problem
Or, "This is easy,
right? I just gotta tilt it, right?"
Note: I'm sorry
if I'm a little slow in getting to the meat of this tutorial,
but I believe that a firm understanding of the problem is necessary
before one can achieve a solution. If you think this is getting
boring, skip on to the next chapter.
It's fun to apply the FE Sphere
filter to an animated layer in fact, that's when the filter
really begins to shine. If the layer is completely solid, there's
nothing much to worry about beyond pleasant lighting. But if
parts of the layer are transparent a ny part that reveals the
back "seam" then you have to be careful that what's
going on at the seam doesn't look crummy.
Take a look at this AE layer:
The top line has half an "x"
on one edge and half an "o" on the other. The bottom
line has exactly half of an "o" on both sides. This
second one is more or less what we're going for apply the FE
Sphere filter to this layer and this is what you get:
It only takes a little bit of effort
to get a line of type to exit in a wrap-friendly matter; AE
can adjust scale and position with extremely minute precision,
and with a bit of dickering almost anything repeatable can be
wrapped convincingly. It also hel ps to design the type (or
whatever graphic element you want to wrap) in Photoshop, where,
with some judicious use of the Offset filter (or even the KPT
Seamless Welder filter, although it doesn't work with type)
you can fine-tune an element so that it com es in without a
With a helical map it's a differrent
matter. A helical map has to follow some basic rules that are
best illustrated with, well, some Illustrations
At first glance a helix seems simple.
It shouldn't even have to wrap, right? It just needs to travel
around the sphere a few times, never touching itself. As a matter
of fact, a simple, one-twist helix is very simple. If you move
your text (or whatever) across the screen, thus:
Then you get a little helix animation
that looks like the "Introduction" graphic on page
1. Cute, but unimpressive most people want their animation to
corkscrew around the object several times. Well, although it
doesn't look like it, in order for an anima tion to do this,
it needs to wrap:
If your animated element is to
spiral around an object, then it needs to exit one edge at exactly
the same speed, size, and angle that it emerges from the other
side. This is "all" your animation has to do to wrap
Stop laughing. Certainly, this
is not as easily faked as a simple, horizontal move. The slightest
difference in angle, velocity, or scale will throw the whole
thing out of whack.
The Problem, therefore, was "how
can I bring the calculating power of AE to bear on this task?"
With a combination of comps and
filters it must be possible to if not actually automate the
process at least make it relatively painless.
The answer looks complicated, but
it's deceptively simple, and depends on a filter the After Effects
eqivalent to a Photoshop plug-in that we've already mentioned:
The Offset filter.
The music swells.
Chapter 4 The Solution
Or, "Cut to the friggin'
for the sake of simplicity I'm going to be mapping a texture
onto the FE Sphere filter, remember that the results of this
technique will apply to any texture -- cylindrically mapped
onto practically any object -- in any 3D program.
All right. I'm going to show you
how to create a helix-friendly animated layer in After Effects.
If you skipped the rest of the tutorial to get to this part,
welcome. If you waded through all the basics, good for you --
you probably have figured out the a nswer by now.
I'm basically going to walk you
through the process step-by step, so, if you have the RAM, go
ahead and open up AE and follow along. We'll skip the math for
now (it's easy, though).
First, create a new project (duh).
Import the Illustrator file "Unstoppable text" from
the folder "Project Files". A file 4000 pixels wide
and 17 pixels high should be in your project window.
Note: It would
be great to use a continuously-rasterized Illustrator file in
this process; unfortunately, you can't apply filters to a continuously-rasterized
Illustrator file. We need filters, so I make my Illustrator
files as big as I ultimately need th em -- one point size for
every pixel in AE -- and they work fine. AE layer dimensions
are currently limited to 4000 pixels, so a 4000 pixel Illustrator
file (or comp) is as wide as we can go.
Make a new comp (command-n) 4000
pixels wide by 500 pixels tall, and make it 15 seconds long.
Call it "4000x500". I know, I know -- we're supposed
to be using a comp with a ratio of 2:1, not 8:1! What gives?
Don't worry about it. All will
Zoom out (command-minus) until
you can see the entire comp in your window. Drag the file "Unstoppable
text" into the center of the comp, where it should snap.
Check its position--sometimes the snap fails with comps this
size -- the positional values shou ld read "2000,250"
. Adjust them if necessary.
Next, zoom in to the upper left-hand
corner of the comp. We're going to rotate the "unstoppable
text" layer and use its own bounding box as a "ruler"
to align the image. We want the lower left corner of the "Unstoppable"
layer to precisely line up with th e upper left corner of the
comp. It should only take a few seconds of typing in values
to accomplish this (if you have a large enough monitor you can
use the mouse tools as well). The only really important thing
is to turn off "Preserve frame aspect ratio " in the
"scale" setting, because you ONLY want to scale the
width of the layer. You want the corners to align like this:
If you want to cheat, these values
will give you the results you need: Scale -- 100.75% x 100%,
Rotation: 7.36 degrees.
Please don't panic at this point;
once you get how this works you will find that this is not as
complicated as it seems. In fact, the precision of this step
is usually not required -- I've only included it because it
yields the best results.
If you zoom out now, you'll see
that the "Unstoppable" layer now stretches perfectly
from corner to corner:
We've just determined the optimal
angle that the "Unstoppable" layer can travel from
corner to corner without encountering the side edges of the
comp. Reduce the horizontal scale of the "Unstoppable"
layer back to 100%. You won't need to deal with the sca le settings
again. Save the project at this point.
you use this technique, always stay away from the side edges
when possible. The Offset filter will take care of any seams
we will encounter, and the Sphere filter will reduce the horizontal
edges of our file to single points, so try to set up your animations
so that the elements only encounter the top and bottom edges.
You're still zoomed out, right?
Making sure the timeline is set to zero, drag the "Unstoppable"
layer until the upper left point of the layer's bounding box
is exactly in the lower right corner of the comp. Zoom in and
use the cursor keys to align it prec isely. If you want to cheat,
the positional values of 5983, 765 should be about right. Click
on the stopwatch next to the "Position" label to set
Move the timeline I-beam to 14:29
(the last frame in the comp). Zoom back out and drag the layer
so that its lower-right point is aligned with the upper left
corner of the comp. Zoom in to get a better look, and use the
cursor keys to adjust the layer un til it is exactly in place.
The values should be -1983, -265.
Now you have an animation where
the "Unstoppable" layer travels from the lower right
corner to the upper left corner in a straight line that is exactly
parralel to the rotational angle of the layer. Drag the I-beam
around to make sure that the motion is w orking and that all
of the keyframes have set themselves properly. When satisfied,
Note: We learned
in an earlier chapter that the FE sphere filter likes comps
to have a 2:1 ratio. Our Sphere comp will eventually be 1000
pixels wide and 500 pixels tall... but we want our type to spiral
around our sphere four times (this number can be an ything within
reason and RAM. For our purposes we're keeping it simple). The
4000-pixel-wide comp is important: we want four twists in our
helix, and the comp is four times wider than our target sphere
comp will eventually be.
Pre-compose the "Unstoppable"
layer. Call the new comp "Unstoppable Comp" and pick
the "Move all attributes into the new composition"
Now it's time for the Offset filter.
It's located under "Distort" in the "Effects"
menu (I'm not sure why. I guess it didn't fit anywhere else).
Adjust the timeline of the comp to around 7 seconds. Apply the
filter, and change the center from "2000, 250" to
"0, 250". Examine the results.
The Offset filter works by shoving
a layer off one side while wrapping it back on the other. It
works with great precision and in any direction, but for this
exercise we'll only be applying it to horizontal values. The
"Unstoppable Comp" should now contai n two separate
strands of text instead of one long piece:
Duplicate this comp three times
(command-D D D). Double-check that the offset values of the
first layer are set to "o, 250" (already set), and
then set the offset values of the subsequent layers to "1000,
250", "2000, 250", and "3000, 250".
The comp shoul d now look like this:
Note: For future
reference, you only really need to apply the Offset filter to
three of the layers, since the one you start out with will be
set to "2000, 250" by default.
Now we're in business. Create a
new comp, make it 1000 x 500 pixels and accept the duration
of 15 seconds. This will be our source comp for our Sphere.
(IMPORTANT: This would also be the layer we'd render if we were
going to map the texture on to an objec t in another program.)
Drag "Comp 1" (the 4000x500 comp) into the new, 1000
x 500 comp:
Drag the I-beam back and forth
in the time-line, and note that anything that disappears off
of one edge immediately reappears on the other. Interestingly,
it doesn't matter in the slightest if the wider comp is centered
right to left or not -- it will wo rk regardless. And trust
me, AE makes sure that this is pixel-perfect. Save.
Now we need to make the destination
comp for our sphere. Assuming most of you are working at video
res, make a 640 x 480 comp, and call it "640x480".
Drag the "1000x500" into the center of this comp,
and don't resize it. The Sphere filter will take care o f that.
Drag the I-beam to about 4 seconds,
so you can see some text creeping up into the window, and apply
the FE Sphere filter. It's located under "Perspective"
in the effects menu. Adjust tohe radius to ".7" or
thereabouts. Your comp should now look something like this:
Render an animation from this comp
and its motion should look something like this:
(click to play)
Now for the math: 1000 x 500 is
a nice, easily divisible size for a Sphere comp to be. Knowing
we will be using a comp this size, our initial, wide comp should
be a multiple of 1000 -- 2000 pixels wide for two loops, 3000
for three loops, etc. One caveat: you can't have a comp wider
than 4000 pixels, so you'll have to jump through some hoops
to get more than four loops using this method. You can of course
reduce the size of the sphere comp to something like 800 x 400
or even 600 x 300, but this will limit the quality of your final
sphere, particularly if you scale it up. And remember, the wide
comp needs to be a multiple of the width of the smaller comp:
an 800 x 400 destination will need a 1600 x 400, 2400 x 400,
3200 x 400, or 4000 x 400 initial wide co mp.
Of course, there's another method
to add more than four loops with a 4000-pixel comp, but I'll
get to it in the next chapter.
Having fun yet? Was it worth the
wait? Does it even make sense?
Chapter 5 - Advanced Techniques
Or, "Thank goodness
Now that you understand the basic
technique, you can start playing with things. First, let's make
Follow the steps to create the
1000x500 comp in the last chapter. Then create a new 1000x500
comp (call it 1000x500 Mark II) and import two copies of the
original 1000x500 comp. Place them both in the center of the
Select the topmost layer and apply
the Offset filter. Change the offset value from "500, 250"
to "250, 250". Now you've doubled the number of lines
in the comp without changing the aspect ratio, so twice as many
lines of type (2) will chase each other around the surface of
Import this comp into your output
comp (the 640x480 one) and render the results. A perfect double-helix
The hi-res 16-loop helix
This one takes a little patience,
and a lot of RAM.
Once you've created the 4-layered
offset 4000 x 500 comp, create a new 4000 x 2000- pixel comp,
and make its time span something more like 45 seconds. Drag
four copies of the 4000x500 comp into the new, bigger comp,
and spread them out vertically so that the combination of the
four covers all of the available space. It's best to do this
by entering positional data: the top layer should be at "2000,250"
the second layer at "2000,750", the third at "2000,
1250", and the fourth at "2000, 1750".
Now for the patient part. Adjust
the time so that the type is exiting out of the top edge of
each layer--ten seconds should do it. Zoom in to get a clear
view of the seam between the bottom two layers. Select the second
layer up in the timeline and drag its "time-bar" over
to the right about five seconds. Now you should have enough
of a reference to adjust the position of the second layer: apply
the offset filter and adjust the values until the paths of the
lines line up perfectly.
Next, adjust the temporal position
of the second layer (drag it around on the time-line) until
the letters align as closely as you can get them. It's not likely
that they will align perfectly--this is one of theose silly
seams we have to create by hand. Get it as close as you can,
then use the mask settings to shave off a pixel or two at the
bottom of the second comp, and nudge with the cursor keys until
the two layers mesh perfectly. As I said it takes a little bit
of patience, but it can be done. Repeat this process for the
other layers and proceed from there to the Sphere filter comp.
Here's proof of a two-layer seam
operation: an eight-loop double-helix halfway into its cycle.
The Gen-yoo-wine Spiral
This is not really that advanced,
but it may not be obvious: when rendering the sphere, turn it
90 degreed on the x-axis and only render the backside. You'll
get a spiral animation! Much easier than motion tracking or
Don't forget that any layer can
be filtered in AE (as long as it's not a continually-rasterized
Illustrator file) and if you apply a filter to the 1000x500
comp before you spherize it, you can get some interesting effects.
It's easiest to play with distortion filters that effect only
the center of the image (hence the front of the sphere) and
not the edges (don't want to muck up that seam, now, do we?).
The Wave warp filter and the PS Twirl are just a couple of filters
that fit this discription.
Just be sure to pre-compify the
1000x500 comp (or the filter will apply to the whole, wide layer).
A little experimentation and you can get effects like this:
The PS Twirl filter:
The Wave Warp filter (Triangle
The FE Kaleida filter:
and Kaleida again:
And Don't forget 3D programs...
map a spiral layer onto a 3D object andyou can get results like
(Click to play)
This texture was mapped onto a
cone. The camera was located inside the object, oriented towards
As usual, the possibilities are
endless... and occasionally dazzling. Above all, blow the socks
off your clients. Well, that's it! A neat trick to impress your
friends. I hope it was worthwhile. Somebody needs to come up
with an acceptable synonym for "comp".
If you found this tutorial to be
useful, let me know. As always, I welcome all comments.
Special thanks to Total
Training for allowing us to re-print this tutorial