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Ambient Occlusion with the Node Editor Revisited

11

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.

About the Author

Avatar image for Bart Veldhuizen
Bart Veldhuizen

I have a LONG history with Blender - I wrote some of the earliest Blender tutorials, worked for Not a Number and helped run the crowdfunding campaign that open sourced Blender (the first one on the internet!). I founded BlenderNation in 2006 and have been editing it every single day since then ;-) I also run the Blender Artists forum and I'm Head of Community at Sketchfab.

11 Comments

  1. 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...

  2. 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

  3. 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

  4. 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. :)

  5. 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."

  6. 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

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