January 12, 2010

Realtime ambient occlusion with AE & Pixel Bender

Ambient occlusion, according to Wikipedia, "attempts to approximate the way light radiates in real life, especially off what are normally considered non-reflective surfaces." Jan-C. Frischmuth, who also did Smart Normal for Pixel BenderFrischmuth explains inRealtime SSAO with After Effects and Pixel Bender:

"Screen Space Ambient Occlusion or SSAO is a method to compute an approximated AO pass in real-time! This is done by using the depth information of a 3D object or scene that has been stored from the Z-(depth) buffer of the renderer.
The disadvantages lie in the nature of SSAO being “screen spaced” which means that it can´t take objects from the off into account, and the result has to be blurred to reduce the inevitable noise. Also there is no ray bouncing, so classic AO is visually superior – but hey… who can argue with “real-time”?"

For related info see previous posts Occlusionist: a new AE filter in beta (unreleased) and Youveelizer filter for UV mapping in After Effects (see comments by Maltaannon). Context for related techniques is shown in How to use UV passes in 2D from VFX Haiku:

How to use UV Passes in 2D from Kert Gartner on Vimeo.

Note: there's new Pixel Bender resources on Adobe.com.

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