| I've always had a strong interest in the use of particles for the oomph and wow factors that it provides. I am embarking on a series of tutorials on the use of particle systems. Specifically, I'll be looking at the particle systems that are installed with Adobe After Effects.
The first in the series of tutorials will cover a little of Particle Playground and Shatter to create a stream of particles that fly on to form a shape resembling a map of the world. You will need the production bundle bundle of Adobe After Effects. Take a look at the completed movie (in the green bar above) to see what's in store for you.
The project file includes all the materials you will need for this tutorial. Yup. Everything you need is created within AE itself - no external files.
We'll start off by using Particle Playground to fashion a grid of dots. We'll then transform this grid into the shape of a map of the world. For these parts, we'll be using Particle Playground's Grid, Layer Map and Persistent Property Mapper features.
Start off by creating a square-pixel, NTSC D1 composition and name it PP_Map_01. Then create a Solid and name it PP_Layer. This will be the compositing where all the action for part 1 occurs. We'll need to create another composition where we will create a circular shape with the Quick Mask Tool. For this, create a 6x6 pixel composition and name it, Shapes. Create a White Solid of the same dimension. With the Solid already selected, choose the Elliptical Quick Mask Tool and double-click it to create circular mask on the White Solid. This shape will be used as the particles that form the grid.
Nest the Shape Composition into the PP_Map_01 composition and click on its eyeball to switch off its view. We'll be using this nested composition as a Layer Map. As such, we do not need to view its source layer. Select the PP_Layer and apply Particle Playground. By default Particle Playground uses its Canon property to shoot off particles and its other particle emitter, the Grid is off. Since we're going to need the Grid property, we'll switch off the Canon. To do so, set the Particles per Second value to 0.
To switch on the Grid, we'll need to have positive Width and Height values. To set the values to be identical to the layer's dimensions, create an Expression for each of the properties, Width and Height by typing "width" and "height" for the respective properties.
Our Composition Window is still empty. To fill the grid, we need to specify the number of columns and rows for our particles. The Particles Across and Particles Down properties does the job for these two properties. Set the value for Particles Across to 70 and Particles Down to 50. Our composition is now filled with lots of red pixels. The red pixels are the default particles in Particle Playground.
To replace the default particles with the circular shape that we created earlier, we need to set the Layer Map property to point to the nested composition, Shapes. To do this, twirl down the Layer Map arrowhead and select the Shapes layer for the Use Layer property. The shapes will now fill the composition window.
We will want to switch off the built-in gravity settings in Particle Playground. Otherwise, our particles will gravitate towards the bottom. To switch off gravity, simply set the Force property for Gravity to 0. We will also want to prevent Particle Playground from creating more particles after the first frame. To do this, we need to create keyframes at the first and second frames in our timeline for the Particles Across and Particles Down properties. At the first frame, create a keyframe for both properties. Leave their values at 70 and 50 respectively. Go to the second frame in our timeline and set the values of both properties to 0. Convert all the keyframes to Hold keyframes. To do this, select all keyframes and press CTRL+ALT+H.
The next step is to fashion our grid to fit into the map of the world. I have already prepared a map for this task. Look for the footage item, bGEMs_Map. Nest this into the composition and switch off its view property. We will use the luminance values of the map to selectively switch off particles that we do not need. In the Persistent Property Mapper section of Particle Playground, click on the Use Layer as Map dropdown list and select the bGEMs_Map layer.
For the Red Channel, set its selection to Opacity with the following values, 0 for Minimum and 200 for Maximum. This extreme value for Opacity is to ensure that all the particles are fully opaque. Your Composition Window should resemble the following image.
We're now done with the first part of the tutorial. We'll move on to using Shatter to disperse the particles. Before we do so, take note that you can use any shape and color for the particles. The grid that you eventually end up with is also dependent on your choice of a black and white image.
We'll look at using Shatter's Custom Shatter Map property. The Custom Shatter Map allows us to define the shape of the particles that Shatter emits.
Create a new composition with an NTSC D1 square pixel resolution. Name it PP_TimeRemap. Nest the PP_Map_01 composition here. Apply Time Remapping by pressing the key combination, CTRL+ALT+T. Delete the second keyframe. This procedure will freeze the first frame of the nested composition. The rationale for doing so is to prevent Particle Playground from rendering frames subsequent to the first frame. All we need is the first frame, the map of the world defined with our shape. Without this procedure, the entire rendering process will take considerably longer.
Now create a new NTSC D1 square pixel composition and name it Shatter. Nest the PP_TimeRemap composition here. Apply Shatter and change its View parameter to Rendered. Within the Shape section, select Custom for pattern. For the Custom Shatter Map property, select PP_TimeRemap. What we have done is to tell Shatter that we want to use a custom shatter map and which layer in our composition to use as the custom shatter map.
Temporarily change the View to Wireframe + Forces to view the custom shatter map and the current force. We will be working with Force 1. Force 2 is switched off by default. The Force is visually represented by the blue circle in the Wireframe + Force view mode. It's size is defined by the Radius and Depth properties. Its location is set with the Position property.
We will now set keyframes so that our Shatter occurs at the 2-second mark and ends at the 10-second mark. There are a number of ways to do this. But the most efficient way, for our current needs, is to animate the position parameter. While in Wireframe + Forces view mode, set a keyframe for Force 1's position such that Force 1 is outside of our Composition Window. I've set mine to [-300,270]. Then move the Timeline Indicator to the 10-second mark and change the value to [390,270]. Initiate a RAM Preview to see the results. Switch to the Rendered view mode before rendering your movie or to perform a more comprehensive RAM Preview.
That's all there is to it. For further experimentation, go to the Shape composition and create a new shape or use one of the alternative shapes I've provided. Switch to the Shatter composition to view the results. Additionally, within the Physics section, set Mass Variance and Randomness to zero. You'll see that the particles now fly off in an ordered manner. To have the particles fly towards the camera, set Gravity inclination to 90. To have them fly away from the camera, set Gravity Inclination to -90. And don't forget that Shatter is a pseudo 3D plugin. It works well with the 3D camera. Suggestions for a beauty-pass include; CC Force Motion Blur, Glow and Radial Shadow.
That's it for now. Peace and God Bless.
--Roland R. Kahlenberg
Please feel free to discuss this technique in the After Effects forum at Creativecow.net
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