Ambient Occlusion with the Node Editor Revisited

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Fake screenspace AO: Render time: 5 secondsBlender’s ambient occlusion renderer produces wonderfully lighted scenes at the cost of LONG rendering times. Mike Pan has created a setup in the Blender node editor that will reduces rendering times by a factor of 60 while still giving very acceptable results.

Mike writes:

Based on inspirations from matt ebb, crytek GmbH, and various papers, I manged to create a robust, easy-to-implement screenspace AO with blender, so here it is! My very own fake ambient occlusion using nothing but nodes!

This method, screen-space ambient occlusion with composite nodes, is also known as z buffer ambient occlusion, or depth buffer occlusion, or image based ambient occlusion, 2d shadow, and z-awesomeness!

Mike is not the first to do this; previously we reported on Matt Ebb’s method for creating an unsharp mask and ambient occlusion using the node editor. And while we’re talking about the node editor anyway, here’s also a trick to mimick Sub Surface Scattering effects.

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    • Eonmach

      Really, positively cool use of nodes, very helpful for my proyect IceQ. Since I changed my mind of working in my short clip code named “IceQ” in Yafray to the internal, due to noise problems and time consuming rendering…
      This is what I needed…

    • unstable

      Would be cool to see these nodes bundled as a new standard node in Blender.

    • http://www.rgbk.org Bmud

      The thing is… the new SVN builds of blender have some sort of not-yet-discussed fancy ambient occlusion that’s A: faster, and B: completely smooth.. :O

    • http://www.mbproductions.biz Mike

      Well whether there’s a new hard-coded AO in the new Blender or not,
      I can appreciate this method.

    • http://sgbzona.blogspot.com/ sgbzona

      nice… I like it.. testing now….

    • KevinW

      well… meh… I have never had speed issues with the normal AO, while I compliment the effort, the quality loss for speed increase really does nothing for me.

      I usually use AO around 2-6 on HD renders. Textures let you get away with this. When I need high settings, I bake it or use yafray (which tends to be way faster in skydome mode).

      I am sure someone will find it useful so thanks for sharing!

      –
      KevinW

    • http://blendernewbies.com Kernon

      This is awesome! Even with its limitations, it can still be a tremendous time-saver for pre-vis. It should do fine in most cases, though. Thanks!!

    • Arek Bal

      Heh… it actually inspired me… and I spent whole day on just doing some abstract node animation. Node Animations – that’s an advantage in compare to mapzone. This technique is cool, nodes are cool. :)

    • Gryphon

      A couple of notes for users who might be unfamiliar with nodes:
      -The “subtract” node used is actually the mix node found in Add>Color… change “mix” to “subtract.”
      –The “sharpen” node is actually the “filter” node in Add>Filter… change “soften” to “sharpen.”

    • Charles (chuzzy) E

      Wow, truly impressive. First Vector blur and now ambient occlusion is simply amazing.

    • claas kuhnen

      mh the shadows look very very dark.

      not sure if that compares to AO?

      I am curious why and how pixels3D was able to provide a lightning fast AO shader
      with raytraced shadows and now NOISE in it. They use a REYES render engine.

      it would be great in case Blenders AO could better use HDRI images.

      for stills you could use bake to speed up rendering.

      claas