|CreativeCOW particleIllusion Tutorial
CreativeCOW leader Elvis Deane has been asked a few hundred times now how he blew himself up using particleIllusion, and until now the entire tutorial of how to do this was only available on his video tutorial CD. So, by popular demand, here is how to blow up your friends or family safely and effectively.
You'll need to begin by bringing in some footage as a background. Here we have an "actor" who was shot against a green screen. In my compositing program, I've used the keying tools to remove that green screen, and then saved the clip out as a sequence of images (PNG) with an alpha channel. So now when we import that sequence into particleIllusion, all we have is an actor standing against a transparent background.
In the Background Image options for that layer, uncheck the Hold Last Frame box. This will make the background vanish after it's stopped playing. We'll also change the End box under Sequence/ AVI so that rather than playing for 65 frames, the clip only plays until frame 58. Once we hit Ok and go back to the scene, hitting play will show us the changes.
We're basically trying to create a duplicate of the actor out of particles so that on frame 58 when the background turns off, we'll have a seamless cut between the video of the actor and the particle version of him that will fall apart.
Place a blank emitter on the stage at frame 1, right-click on it and convert it into an area emitter. If you don't have the blank, grab it from the Wondertouch downloads page. Resize it so that it covers the actor entirely on frame 58. At this point, it isn't doing much, but a few changes will get things going.
We'll start by sliding the Active graph over to frame 58, so that the particles only begin to appear on that frame.
Set a keyframe on the Number graph so that 100% of the particles are appearing on frame 58, and another key at frame 59 with a value of 0.
Turn up the main Visibility graph to 100% from its default of 50. This will make it a smoother transition between the video actor and the particle actor, and require less particles to make the effect convincing to the eye.
The real key of the process is in the emitter's Colors tab. Choose Get Color from Layer in the radio buttons under the color gradient. Now the particles will pick up their color from the video clip of the actor and create a duplicate of him. Under the transparency gradient, choose Get Transparency from Layer so that particles appear only where the background image is opaque, in this case where the actor is.
We can't really see anything right now because there are so few particles, so it's time to bump up the particle type's Number graph to something really high. 2000 is a good final number, but if you have a slow system, consider keeping it lower as you work on the scene, then increase it at render time.
If we hide the background at this point, you can see the current state of our particle duplicate. It's a good start, but two things are really needed.
One is much smaller particles, which we can do by knocking the Size graph down to about 5. Ideally, you probably want your particles to only be about a pixel big so that the transition from the video actor to the particle clone is seamless.
The second thing needed is a lot more particles, since right now all we have after frame 59 is a few pixels floating around. That's something you can do at render time, just going to the emitter's overall Number graph, and changing the value at the frame your actor vanishes to 2000%.
Now comes the actual artistic portion of all this. Depending on how you want the particles to move, you can adjust the Velocity, Weight, and other graphs to either make the particles fall away or rise up. A healthy dose of Motion Randomness can really help out in selling the realism of the effect here.
You can also add Force objects to push the particles around after the actor disintegrates and give a more dynamic feel to the scene. Try putting a few small ones on the stage with different Direction and Strength settings to get a more realistic "wind blown" look.
And again, once you're ready, just crank up the main Number to 2000% and render it out. Adding motion blur is something that's very important to getting some realism. Otherwise, it all just looks like a lot of falling dots.
Voila! You've just disintegrated someone. Add some death ray effects, or some fiery particles for the Buffy/Blade look, and you're all done.
Just a side note- If your actor's legs are offscreen and you want the particles to fly upwards as if the wind is carrying their remnants up, you'll run into a bit of a problem. Since there's no video off-screen for the emitter to know where to make legs, and what colour to make them, nothing will appear from where the actor's legs would be.
Copy and paste a duplicate of your Disintegrate area emitter onto the stage and position it offscreen where the actor's legs would be. You'll probably also want to resize it a bit. Rename it Legs, and go into the Properties. In the Colors tab, select Use Full Gradient for both the Color and Transparency gradients. Next pick a series of colours similar those of the actor's pants. Now when you playback the scene, it will look as if the legs are dissolving as well.
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