Ever noticed that Ambient Occlusion doesn’t happen in the real world in lit areas? It’s more of a darkness thing… so why apply it everywhere?

With this Rendertree compound you have AO in darkness and that’s it. Simple! 🙂
Notice how there's no AO in lit areas

Shadow AO compound

Now….. can you spot the differences between these images below?

Diffuse pass, boring looking, no AO:

BAD — Sloppy AO that’s been applied everywhere: (notice how dirty it looks towards the center light)

GOOD — Shadow-aware AO, only exists where it should… in darkness:

Credit where credit is due; this method was originally pointed out by Guy Rabiller many years ago, back when our software was called a 3 letter word.

9 comments so far

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  1. The compound is simple, but very intelligent!. Thanks

  2. Nice tip, very useful for realistic lighting.

  3. nice compound !

    and BTW I just love your site,
    the way snow dots fall and how the
    images smoothly appear when i scroll down.. 🙂
    i know its completely irrelevant,
    but i can’t help myself

  4. A very useful tool

  5. This is brilliant! Silly question though, how do you install this rendertree compound?

    • You can use it without installing by dragging the .xsirtcompound file directly into a rendertree, but you can also install it to your user root under \Data\Compounds\.

      If you don’t know where the User Root is, go to File->Plugin Manager, rightclick on “User Root” (next to a green folder icon) and click Explore. In the folder that pops up, go into the Data folder, then if you don’t see a “RTCompounds” folder, make one and put the .xsirtcompound file in it. After that, next time you open Softimage it will appear as a custom rendertree node if you search for it.

      If you have any problems leave another comment reply.

  6. Exelente

  7. I like that .thanks very much

  8. fantastic! thank you!