Creating an Animated Volume Meter : Adobe After Effects Tutorial

A CreativeCOW Adobe After Effects Tutorial

Talid Al Khatib
Damascus, Syria

Article Focus:

One of the most fun and useful things in Adobe After Effects, is linking the motion of your project components with music. In this tutorial from Talid Al Khatib, we’ll create a “volume meter” that responds to your music.

Movie

Project zip

Part One: Creating the Volume Meter

Create a 320*240 composition.

Import three solids: red, yellow, and green, each the size of 50*70 and arrange them as a volume meter:

Now we need to give it the look of real volume meter. Let's pre-compose the three solids, by selecting them, and pressing Ctrl+Alt+C and choose the option “move all attributes into the new composition” and name it volume meter.

Import a new solid the size of the composition and lay it over our new pre-composition.

On this new solid we’ll apply the grid effect, from the Render group. Give the Border the value 4, and the corner the value 226, 128, so there are no vertical lines over our volume meter.

Change the track matte of the volume meter layer to "Alpha inverted matte" and you'll get something like this:

Now again, precompose the two Layers, let's name them volume meter (again) and apply the Glow Effect from the Stylize group, and we have our volume meter.

Part two: let it move!

We need this volume meter to respond to music, lets import a sound file, drag it to time line, and then right click it.

From keyframe assistant choose "convert Audio to keyframes" and you'll have a new layer called "Audio Amplitude". Click the small triangle on the next to the layer, choose effects, then click the triangle next to "both channels" you'll see a stop watch next to the word "slider". keep it opened, because we'll need it soon.

On the volume meter layer, apply the Linear wipe effect from the transition group, make the wipe angle 180.

Alt click the stop watch of the "transition complete" and drag the pick whip from transition complete to the slider in the Audio Amplitude Layer:

You'll notice that this is not the result you wanted as the red area is moving slowly and in the opposite direction.

Let's correct this by going to the transition complete, where we see the following expression written:

thisComp.layer("Audio Amplitude").effect("Both Channels")("Slider")

Press the expression -so you can edit it- and at the end of it write *-2+100, so our new expression will be:

thisComp.layer("Audio Amplitude").effect("Both Channels")("Slider")*-2+100

If you don't care to know what this addition did, it's ok but if you do, here's what happened:

When we gave a transition angle of 180, we meant that we wanted the transition to be from up to down, then we linked it to the audio keyframes. The problem with those keyframes is that when there is no sound, they have the value of zero, and they have greater value when the sound is louder. So, by adding 100 to the transition, it makes the transition has a 100% value when there is no sound, by multiplying it with a minus number, it moves. Let's say that the music keyframe has the value of three, the result of the transition will be: 3*-2+100=94.

Why -2 and not -1? Because the differences between keyframes values are very small, so we have to "amplify" these differences by multiplying them.. you can try other numbers, but the result will be very extreme and not realistic.

Part three: 3d it...

Our job is technically done, but we still can add some fun to our composition.

Create a new composition, and drag comp1 to it. Duplicate it three times, so we have four copies of it. Name the layers: front, back, left right, and turn them into 3d layers.

Give the four layers the following transform values:

front: change the y position to 95
back: change the z position to 50, change the y position to 95
right: give the y rotation a value of 90 degrees and the x position the value of 185, change the y position to95.
left: give the y rotation a value of 90 degrees and the x position the value of 135,change the y position to 95.

now add a new layer, make it 3D layer. give it the following values: position values: 170,203,0

Add a new spot light, with the option cast shadow turned on. from the material option of each layer, activate the cast shadow option.

Add a new camera, and add the following expression to the position property of the camera: [Math.sin(time)*z,y,Math.cos(time)*z]

where z is the zoom value of the camera, and y is y position of the targeted layers, in our case the expression goes like this:

[Math.sin(time)*507,120,Math.cos(time)*507]

You'll notice that the camera is now moving in a circle around our volume meter.

enjoy it...

*tip of the day: for the expression guys, instead of writing the long boring: Math.paw(time,2) just write: time*time.. it will do.

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Comments

Creating an Animated Volume Meter
by gareth holloway

Cool tutorial.
Although the 3rd part didn't work for me for various reasons.
1: When I added the 3d transformations they just went in all directions and didn't look at all like a 3d version.
2: I couldn't rename each duplicate of comp1. Dunno if this was my lack of knowledge but anyway.
3: When adding a new layer I didn't know what kind of layer to add (As mentioned earlier).

So part 3 I failed at but I got some cool knowledge from the rest thanks.

Creating an Animated Volume Meter
by Jared Brown

There is a section close to the completion of this tutorial where you say "now add a new layer, make it 3D layer. give it the following values: position values: 170,203,0."

What kind of layer are you telling us to create? Is it a shape layer, solid, null object, adjustment? I'm new to this program and I'm stoked to learn it. These tutorials are good I just need to know what type of layer? I can't get it to work properly for some reason using a shape layer. Does the order of the layers matter too? Should this additional layer be below the front, back, right and left?

Thanks!

Creating an Animated Volume Meter
by Ryan Brien

Thanks for the great tutorial. Here's a video I created using this tutorial.

http://www.youtube.com/watch?v=ISXRmwI-v54

Creating an Animated Volume Meter
by Leonardo Boher

Very useful tutorial!!! Thank you very much for sharing your knowleddge :) I'm pretty new using After Effects but I'm learning plenty of things these days :)
I have a little question. I have used other scripting values instead the ones you mentioned in the tutorial (obviously, those values can vary depending on how I have created the 3 solids about its dimentions). As I can see, *number means like a coarse amount of -number and +number. My question is about the minus numbers and the plus numbers. They seems to adjust the range of the effect. - means the lower value and + the top value, am I right?