2005-03-02

 

Ambient occlusion

Ambient occlusion is really cool. Yeah, precalculated occlusion for animating objects is fake, but with some hacks it's still very cool. Why I didn't use it before? :)

Here, a small shot comparing no-AO with AO (super small because it's still work-in-progress, I'm not sure if my teammates would be very happy with me showing big screens :)).

Ah, at the bottom there are "my" soft shadows that I've written about earlier, but nothing can be seen in such a small shot. Oh well; shadows will be the story for another day.

Comments
This is going to be awesome :)
 
Heh, the hard part is not showing work-in-progress shots, but actually finishing and polishing the demo :)

Thanks for the comment, anyway.
 
I have a question: as i've read, ambient occlusion is tracking rays of light that bounce of off other surfaces. So the amount of light in the scene should be higher when AO is on. So why in your AO shot, pieces of the character apear darker than in non-AO shot?
 
Not really.

AO is basically calculating how much each point on some surface is "open" to light. In essence, it calculates the illumination if the object would be surrounded by many lights such that their total intensity is some needed value (usually somewhat brighter than "white").

Now, whether it's such simple AO, or AO that also accounts for some light inter-reflections, is only an implementation question. In my current implementation, I calculate only direct visibility, with no interreflections.

The reason why non-AO shot is bright is that it doesn't have any shadows. Hence the "insides" if the character are bright (but logically, they shouldn't be). Why it doesn't have shadows, is another question of course :)
 
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