[Continued from Page 2]

Making the Gradient
We'll skip the Custom Shape tab, although isn't it nice to know that you can your particles can have a custom shape? We're headed for the next tab, which is Scatter Wipe.

Go to the last pop-up in that window and select Custom from the pop-up: we're going to create a Graffiti gradient that's going to invisibly direct our particles from behind the scenes.

Down in the timeline, twirl down the 2D Particles Advanced track, where you'll find the Wipe Gradient track. Set the Media pop-up to Gradient, which will open the Boris Gradient controls.

(Note though that the default is for the Wipe Gradient media to be the same media as the track itself. That's not what we want, but it's clue that you can in fact use ANY kind of track to manipulate the wipe function, including a movie. Future tutorials will look at this very option.)

The white gradient marker, or "color stop," is highlighted,indicated by its triangle "hat" being filled in. In that state, any clicks that you make just below the gradient bar will add a new white marker.

For now, just slide that white marker to the middle of the gradient. Then click the black color stop on the left to activate it, then click below the gradient bar on the right side, about as far in as the black color stop is on the left.

Above the bar are little diamonds that indicate the midpoint of the gradients. By adjusting those and the indicators below, you should wind up with a gradient that looks something like this.

Note two things. One is that you can save this gradient for using later, or load a previous one that you've made or otherwise have on hand, such as the gradients in the Video SpiceRack.

The other is that, while we're using a grayscale gradient to invisibly direct particles, you can also make visible gradients of any colors you want, for things like the surface of letters, or background slabs on lower thirds.

Click image to play movie. 500K. Hey, maybe I should have named this effect "Sands of Tim" after all.

Click again on the 2D Particles Advanced track to bring those controls back to the front. We'll make one more quick change, which is to ramp up the Wipe Gradient parameter to around 1600 or so. This serves to slow down the timing of the wipe, which we'll play now. Load that thing to RAM, and play it. (Select Preview> Preview to RAM, or hit control-zero on peecee, command-zero on Mac.) You can see what it looks like here, by clicking on the image.

Notice as my version plays that the background is blurred. I didn't do this in Premiere (which I used to render my effect), but in Graffiti itself using the technique I hinted at before.

This movie is a pretty nice simulation of our title turning to sand as it falls inward from the edges as the gradient directs. It's a variation on a Displacement Map, which uses gradients to move the pixels in a visible layer according to the luminance values in the displacement map.

We're using it in one of the simplest ways possible: the visible pixels on our text layer that move first are the ones mapped to black on the gradient, and the ones that fall last are the ones mapped to white. As the gradient progresses from black at the edges to white at the center, our wipe moves in exactly the same way, from the edges in, with gravity pulling the particles down.

Next: A Tweak and a Cheat