|Creating the Light Storm
The light storm effect is a simple principle. We will open up our shutter all the way to 360 degrees and drag stuff across screen. With motion blur clicked on, this will create a smear of color that we can later add effects and bend around objects. This has proven to be the most useful clip in my digital spice rack.
To start we will make a color wall of splotches and paint blips to smear across the screen. 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. Change the color and brush settings for different densities and featherings. Make sure to use white in your masterpiece so that we have a 100% bright value to react to Trapcodes Shine later. The finished work should resemble something your three-year-old would paint on the wall with crayons.
Next, select only under the composite paint pull down so that we have areas of transparency. Save a frame with its alpha (I called it Whoosh 1) and import the still into the project. 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) and import into your project.
Create a new 2 second comp in your preferred size. I use NTSC D1, 720 x 486. Drag your two still paintings into the comp. Now comes the fun part.
Drag Whoosh 1 just out of the left side of frame and set a key frame. Go up to the 20 frame mark and drag the painting all the way to the right just out of frame. Now scale down the height values at the beginning and end of the shot with a key frame in the middle set at its full height. This allows the whoosh to enter and exit frame as a sliver while expanding in the middle.
Do the same with Whoosh 2. Now copy the clips and alternate them across the two second timeline so they overlap. Start some at different entry and exit heights to change it up a bit. Preview the shot and adjust to taste.
Click on the picture to view larger picture.
There are no rules here. Make some of the clips longer than twenty frames to vary the speed of the light storm. Note how the splotches of color react differently to the blur. You may even want to go back and write over your painting with bigger or smaller splotches until you reach the desired effect.
I used add in transfer modes to really beef up the light values when they pass over each other. You can experiment with different transfer modes or even add more effects.
When you are satisfied with your whoosh motion across screen, pre-compose the layers and add Trapcode Shine to the whole thing. Play with the ray length and boost light settings. In the Shine effects panel, the transfer settings will really affect the look of your light storm. Select none if you want to lose your original colors and let shines colors take over.
Render out this two second clip with its alpha and you now have a handy light storm that you can use for many different applications. You might want to render out a generic raw version of your colored light storm without shine applied to allow for more flexibility later.
Bending the Light
Now we can drop our light storm into our scene. I use Bezier Warp under the distort effects panel. With Bezier warp you can precisely bend the light storm to fit the scene while key framing the motion to sync with objects or figures. If you need to change the direction of the light storm, set the width scale to (minus) -100%. You can also rotate the light storm into a start position for bezier warp.
Bezier warp is simple to use. Move all of the vertex and tangent handles into position to achieve the desired bend. The image can get a little chunky when tangents are crossed in an abnormal way. It takes some practice but I have had no trouble bending the image 180 degrees although I might have trouble twisting it into a pretzel.
A soft edge mask may be needed to soften the ends if your light storm finishes in the middle of frame as in the hockey puck illustration.
As always, use transfer modes to taste. You can also use your new light storm clip as a displacement map, track matte or as a compound blur element. Dont be afraid to add more shine to the already shined light storm for some interesting results.
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