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An Introduction to Motion, Part 3Particles of the first part
Particles, as you're probably aware, aren't just for creating explosions. They're also useful for fluid effects, clouds, waterfalls, fog, dust storms, fairy dust, rain, snow flurries--pretty much anything that involves a bunch of little things moving around in a composition. Motion itself ships with a hundred-some-odd individual particle presets, including all of the aforementioned, and then some. Nevertheless, the good folks at Apple, being perhaps a bit less anti-social than you and me, perhaps a bit more tasteful, have left out a number of important categories, chief among these being the "Bloodsport" category--you know, those gushing fountains of blood that make life worth viewing on the TV screen.
I myself am in the process of assembling my own library of Bloodsport particles, which I intend to share with you when it's complete. In the meantime, I'll show you how to get started on your own, with, as always, the intention of teaching not just the specifics of this particular effect, but methods for working with particles in general. For this exercise, we'll create a somewhat exaggerated gout of blood that shoots upward and outward (toward the camera) in pulsing spurts, as if from some horrible neck wound. And we'll make it out of just one image--a tiny blood drop created in Adobe Photoshop--to keep things simple for this initial tutorial.
And before we get started, if you're not yet familiar with Motion, you might want to go back and have a look at the first two introductory tutorials in this series:
? Part 1: General Overview (covering particles, masks, text, animation and filters)
? Part 2: Behaviors (covering a wide range of topics related to Behaviors)
Starting from scratch
Rather than just walk you through a modification of an existing particle preset to create the blood effect we're working on today, I thought I'd go ahead and show you how to do it from scratch. It sounds like it might be more difficult than working with an existing preset, but it's actually a bit less troublesome.
All particle systems--whether 2D or 3D--include two common elements: an emitter and the particles themselves. The emitter is (usually) an invisible point or shape from which the particles shoot. The emitter is the gun, the particles the bullets. The particles themselves can be any type of images, moving or still, and you can combine multiple images and image types in a single particle emitter. (Note that when using multiple images for a particle system, the options available for controlling the particles are different. We're using a single visual element for this particle system.)
So, to begin, we're going to create the image for our particles. Since we're making a gushing blood particle system, we want our particle to be small, red and blobby. I've done this with both still images and moving images, and either one works fine. For a still image, use a program like Adobe Photoshop, and make sure you save it with transparency. You can use native Photoshop files or other formats that support transparency, such as TIFF. (Just make sure you rasterize any layer styles used in the image before bringing it into Motion. And for a moving image, make sure you render with an alpha channel using a QuickTime codec that supports alpha channels ("Millions of Colors +"), such as Animation or "None." Here's an enlarged view of the image I'm using for my particles.
The actual size of your particle image should be anywhere from 5 x 5 pixels to 15 x 15 pixels. Anything larger than that, and you're just wasting processing power because you'll need to scale it down for the effect to look right. Smaller particles will give you more of a granular effect; larger ones will give you more of a fluid effect. It just depends on what you want. And speaking of processing power, you're not going to see much of a difference between moving and still particles when they're at this tiny scale, so you might as well use a still image; it will work more smoothly and take up fewer resources than a moving image.
After you've created this basic particle image, open Motion, and create a new composition. Set the duration to whatever length you want for your particular particle system. Particle systems aren't necessarily confined to the length at which they're created, but if your system incorporates any keyframing--such as fading out or trailing off at the end--then these parameters will indeed be of a fixed duration. (Note, however, that the duration of the particle image/movie itself does not have to match the duration of the composition. If it comes up short, they'll simply be looped throughout the duration of the particle emission.) Also make sure that you adjust your play range to match the complete length of your project. (Do this by dragging the little Play Range triangle in the mini-timeline all the way to the right, as seen below.)
Now that you have your new composition, import your particle image just as you would any footage, and place it in your canvas.
Select the image in the Layers palette.
And then click the "Make Particles" button up in the top tool bar above the canvas. (Alternately, you can also just hit the "E" key on your keyboard, and it will convert your image into particles.)
Related Keywords:apple motion, particles, animated blood
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