LIGHT STORM
The light storm effect is a simple principle. We will open up our shutter all the way to 360 degrees and drag a custom painting across screen. With motion blur clicked on, this will create a smear of color that we can later add effects and bend around objects using Bezier warp. This has proven to be the most useful clip in my digital spice rack.
This three part tutorial will begin with using Vector Paint to create a color wall of splotches and paint blips that we will smear across the screen in part two, a description of Shutter Angle and Motion Blur. In part three we will use Bezier Warp to distort the light storm to conform to our scene.
USING VECTOR PAINT
Vector paint is a powerful tool that has many uses. We will use vector paint in a simple way to create a sloppy painting that will be the foundation for the finished light storm.
Create a 1200 x 300 comp and then drop in a layer of the same size. This will be your canvas. I suppose you could make it wider so it lasts longer when we smear it across the screen in another comp but this is the size I used.
Add the Vector Paint effect to the layer and put your painters pants on. The idea here is to splotch color strokes all over the screen. The reason for using colors is flexibility. You can always dial out the color for a monochromatic storm later.
The vector paint toolbar is self explanatory. It includes hard and soft edge paintbrushes, color selector, eraser, and a selection tool. Vector paint allows only one layer of undo. You must use the arrow in the toolbar as apposed to the undo in the edit menu. The effects menu allows you to change brush settings for different densities and featherings or you can quickly resize the brush by holding down the control key (windows) and dragging until the desired diameter. After some practice, youll be a pro. Make sure to use white in your masterpiece so that we have some 100% bright values that we will affect later. The finished work should resemble something your three-year-old would paint on the wall with crayons.

Use broad strokes and thin lines while making sure that the painting isnt too dense. Youll want some blank space in the canvas so we have transparency in our finished light storm. If needed, use the eraser tool to brush away some of the paint. With the selection tool (arrow) you can modify any of the strokes by lassoing the area or holding down control (windows) and dragging a bounding box around the area. With a paint stroke (or several strokes) selected, you can easily delete, move, change the color, or modify the feathering.
Next, select only under the composite paint pull down which will drop out the background of your solid and allow for transparency. As I mentioned, vector paint has many uses. I wrote another tutorial that explains using vector paint as a powerful masking tool.
Since we will only be using a still picture, set the playback mode to All Strokes. Vector paint has many cool options that we wont go into in this tutorial but just for fun, try selecting animated strokes and do a ram preview. You should see all of your strokes magically write on. Vector paint memorizes the way you painted each stroke and animates them for the duration of the clip with a speed control parameter. You can also make the paint strokes squirm with the Wiggle Control menu.

When you are satisfied with your painting, save a frame with its alpha (I called it Whoosh 1). Using a still instead of the original comp will reduce rendering time later when we wipe it across screen.
Since you are now a gifted painter, go back and repeat the painting exercise with bigger splotches or with more horizontal lines or whatever. Just make this second painting look a little (or a lot) different from the first one. This will allow for more complexity in our finished light storm. We dont want to see the same image pass by like Fred Flintstones window cycling over and over in the background.
Again, save your new painting as a still with alpha (Whoosh 2).
Lets move on to the second part of our tutorial where we will convert our two paintings into a light storm using Motion Blur & Shutter Angle.
Did you miss one of the sections? View:
Part Two: Motion Blur with Shutter Angle and Phase Settings
Part Three: Bending Light and Other things with Bezier Warp
Bill ONeil
www.chicagospots.com
Discuss this technique or others in the After Effects forum at CreativeCOW.net.
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