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Filed under: Motion Graphics •Tips •

After Effects Tips 5: Going for a Scroll

It seems such a simple idea: a banner scrolls across the top or bottom of your comp, repeating the same few words over and over, and doing so seamlessly for as long as you need.

Here’s how to create such an animated banner in After Effects, using either the Offset (or Motion Tile) effect or the Autoscroll animation preset. If you have After Effects CS4 and would like to follow along, download the CS4 project file: AE-Tips-5_scrolling_CS4.zip

The Big Picture

The finished animated banner will loop seamlessly. This version was created with the Offset effect, but Motion Tile can create the same seamless loop.

Here’s the basic idea and workflow:

• You create a “setup” precomp that will hold the text that will scroll, making sure the precomp is at least as wide as the final comp.
• Nest this precomp into the Final comp and apply the Offset (or Motion Tile) effect.
• Don’t try to perfect everything at once; start by doing a rough layout and test the process, then go back and forth adjusting sizes, spacing, scrolling speed and motion blur to taste.
• If you need the banner to loop seamlessly, see instructions on page 2 for looping Offset or Motion Tile.

The Setup Comp

The first step, no matter which effect you use, is to create a precomp to hold the text (or text/graphics) that will scroll. The advantage to having a setup comp is that you can easily adjust the spacing around the edge that “wraps around.” You can also easily create multiple layers or add icons or logos.

For this example, let’s assume the final comp is D1 (720x486) and 15:00 in duration.

The precomp needs to be at least as wide as the final comp (720 pixels or wider) - otherwise it won’t fill the width of the Final comp and the effect won’t look like an “endlessly long layer.” However, if you make the precomp exactly 720 pixels wide, then as soon as one word scrolls off the left side, the same word will immediately scroll in again from the right side. This tends to be a little predictable, so create a wider precomp; this also gives you a little wiggle room to scale down the layer in the second comp if you later find the text is too tall.

As for duration, make sure it’s plenty long enough to fill the Final comp’s duration. Since the precomp is basically a still image, go ahead and make it a minute long so it never comes up short.

If you don’t have enough text to fill the precomp (let’s say you just need to repeat “Breaking News” or “New Releases”), then simply duplicate the text as many times as you need. Consider adding a bullet, icon, or tiny logo between each set of words; this not only adds interest, but helps the reader know where one phrase stops and another starts.

Our setup precomp is 1200 px wide and contains two phrases, with a red star between them (above). Notice we left some space on the right side, so that the last word would not butt up against the first star when the banner is scrolled. The timeline has a total of four layers (below).

In this example, we used two sentences and added a red star between them. The precomp is 1200 px wide; the width is determined by the length of the text, not by any magic formula. We aimed to create the text and icons at the final size, so we don’t have to scale it down in the Final Comp. The height is 60px, for efficient rendering.

If you move your elements flush with the precomp’s left edge, then you can more easily tweak the width of the precomp in Composition Settings > Advanced tab by setting the Anchor to left edge (the next figure below).

If you keep your elements flush left in the precomp, you can easily add or trim a few pixels from the right side of the comp in the Composition Settings > Advanced tab by setting the Anchor to the left edge.

Once you’ve made a good stab at the Setup precomp, nest it into the D1 Final Comp and position it where it needs to go. At this point, you might decide the banner text is too large or too small, or you don’t even like the font, so edit back and forth until you’re satisfied.

Option 1: Using the Offset Effect

To animate the banner, you apply Effect > Distort > Offset to the setup layer that is nested in the Final Comp. Offset is a super easy effect with one parameter you need to be concerned with: the “Shift Center To” effect point. The default value will be equal to the center of your layer (width and height). So in our example, this value will be 600, 30 (half the width of 1200, half the height of 60). The result is that the layer is not shifted using the default settings.

The default settings for the Offset effect shifts the center to the center of the layer, so nothing will appear to happen at first.

If you’d like the banner to start off with the first phrase of your text appearing flush left in the Final Comp, edit the Shift Center To value until it looks like the left edge of the precomp.

To animate the banner:

• At 00:00, toggle on the stopwatch for the Shift Center To parameter.
• Move to the end of your comp, and scrub the X value for Shift Center To; add the Shift key while scrubbing to move in bigger increments. If the second X value is a negative value, the layer will shift from right to left, which is the more usual effect.
• Scrub the timeline, and focus on where the precomp wraps around itself, making sure the spacing looks consistent and the edge is seamless. You may need to revisit the precomp and make some small adjustments.

As the banner scrolls, check the wraparound point carefully. Here, we have too much spacing at the end of the second phrase in the precomp, which causes the spacing at the wrap point to be inconsistent (above). To fix this, either take a few pixels off the width of the precomp, or tweak the position of the elements until it looks even. Tweaking the text tracking is another easy fix (below).

• RAM Preview the Final Comp and adjust speed to taste by adjusting the value of the second keyframe. (If you need to set the speed in pixels per second, check out the Autoscroll preset on Page 2.)
• If you want a little motion blur, you’ll need to apply it using Fast Blur or Directional Blur. (The Offset effect does not honor the Motion Blur switch.)

Now that you have a handle on using the Offset effect, let’s see how the Motion Tile effect compares, as well as show you how to make the banner seamless loop…

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