I thought that for this article I would look at a hidden gem of After Effects, and it is an effect that you definitely need, and you don't even know it.....yet! The effect I'm talking about is "Offset". Let's take a look at how the Offset effect will save you alot of time and work!

Here is a situation that you probably experience on a semi-regular basis. You are creating a background "look", and want to have some text scrolling across the screen, and you want it to loop until the end of your animation. What most beginners (and some intermediate to advanced users as well) do is create a massive layer in either Photoshop or After Effects, with the text repeated over and over again, then they bring it into After Effects, and scroll it over the entire length of their composition. Well, there is a much easier way to achieve this, and it is by using the "Offset" effect. Let me show you how this works. First, let's create a layer of text, and I'm going to use Photoshop to do it.

I've created the text layer at DV frame size, as that is the comp size we will be using in After Effects, but this will work for any frame size as long as the Photoshop and AE frame sizes match. I'm going to save the image as a PNG file, and now, let's import it into After Effects and drop it into a new composition. You can have After Effects create a composition the same size as your PNG file by simply dragging the PNG file onto your "Create Composition" button at the bottom of the project window.

Now that we have a composition with our PNG file in it, let's add the "Offset" effect to it, and you can find it under EFFECT>DISTORT>OFFSET. As you can see, when you apply the effect, nothing happens. Select your PNG layer in your composition and press "F3" to bring up the effects window. Now you can see the "Offset" effect, and its one parameter "Shift Center to".

What "Offset" essentially does is shift the center point of your layer, and move the contents of your layer accordingly. Let's see this in action. Put a keyframe for "Shift Center to" at the start of your composition, and then jump down three seconds. At this point we are going to put in another keyframe, and we want it to have shifted the center by the length of the frame. Even though I know that the value of the keyframe will be -360 (360-720, which is the width of the frame), let's just say for argument sake I wanted to offset the image by 600 pixels. Instead of pulling out the calculator to figure out what 360-600 is, I can simply type that into the keyframe window in After Effects, and AE will do the math for me. This is a pretty handy Easter egg that works with any keyframe value. Now that we have two keyframes, let's take a look at our animation.

As you can see, we now have our effect "loop" one time over three seconds. The great part about "Offset" is that I could set the "X" value to -50000 if I wanted to, and the layer would "loop" for a long time. The only downside to "Offset" is that applying Motion Blur to it has no effect, as technically the layer is not moving, it's "Offsetting", but a simple "Directional Blur" (EFFECT>BLUR>DIRECTIONAL BLUR) would take care of that.

If there is anything you would like to know about editing techniques, feel free to drop me a line at kevin@reelclever.com, and maybe your question will be the topic of my next article.