• Adobe After Effects

  TIP: How to create a Digital Interference effect…

  Posted by Eric Barker on March 20, 2009 at 9:30 pm

  In playing around with some things, I found a pretty good way of creating a Digital Interference/Horizontal Tearing effect, and thought I’d share it with the forum, in case anyone wants to do something similar in the future. To summerize: it involves using a the “Displacement Map” effect, mapped to precomposed layer which uses the “Fractal Noise” effect set to “blocks”. There’s a little more to it than that, so I’ll go into more detail.

  1) Create a new comp, name it “precomp_Digital Interference” (I use “precomp_” to denote compositions that are nested inside of master layers).

  2) Create a gray solid, value “808080” (50% gray)

  3) Create a black solid above the gray solid. Name the layer “Interference”.

  4) Throw the “Fractal Noise” effect on the “Interference” layer. Set the Fractal Type to “Dynamic Twist” and the Noise Type to “Block”, and lower the complexity to 2 or 3. Under the “Transform” attribute in the effect, uncheck “Uniform Scaling” and set the width to around 150, and the height to about 50.

  5) Animate the fractal noise effect either by setting keyframes, or (more conveniently) create an expression: “time*1000”, which will automatically animate the evolution no matter how long you make the comp.

  6) set the blending mode of the layer to “Add”

  7) Create another black solid, name it “Interference Mask” and put it on the top of your comp.

  8) Add the “Fractal Noise” effect to it. This time, set the type to “Basic” and noise type to “soft linear”. Boost the contrast up to about 400, the brightness down to around -60, set the scale to about “200%” and the complexity to 2.

  9) Once again, animate the evolution property by adding the expression “time*200”

  10) Turn off the “Interference Mask” layer, and set the matte type of the “Interference” layer to “luma matte”. This will create an extremely feathered mask so that the interference only occurs in certain areas of the screen. You can play with the attributes of the mask layer to make your interference be more or less uniform.

  11) Create a new composition, this will be your master comp. Throw in any footage you wish to add the interference effect to. Then throw in the “precomp_Digital Interference” composition, but turn the eyeball off.

  12) Add the “Displacement Map” effect to your footage. Set the Displacement Map Layer to “precomp_Digital Interference”, set the “Max Vertical Displacement” to 0, and set the “Displacement Map Behavior” setting to “Stretch Map to Fit”.

  13) Now you can play with the “Max Horizontal Displacement” to give the footage more or less interference. Animate the setting to increase or decrease the interference over time.

  14) tweek any of the settings until you have something that looks good.

  I used this effect in conjunction with some elements shown in the Old TV Look tutorial by Aharon Rabinowitz, and got some great results.

  Television Producer
  KTVF-11 Fairbanks, Alaska
  video.ericbarker.com

  Eric Barker replied 17 years, 5 months ago 1 Member · 0 Replies
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