What is the goal of ambient occlusion?

I didn’t know what it was until I read the release notes where it says ‘dirt filter’ then I realized that all the splotchy noise in the pictures was actually intentional.

Why is the goal to emulate all the problems with film? I always thought that blur, grain and noise was something to be avoided in photography, and one of the reasons why 3D art is so nice.

I realize that there is skill in being able to reproduce all the imperfections of a photograph, but is ‘skill’ synonymous with ‘art’?

If you put the samples on “16”, then it won’t be grainy.

The goal is to simulate GI, a type of ambient light that occurs in real life, creating soft, subtle shadows on objects.
It is used for indirect light, and can also help show the modeling, if it looks too flat.

trying to correct - it’s not GI, it’s more a distance-based shadow. AKA dirt shader, because it produces darker areas where geometry is closer together, be it different objects or wrinkles and folds on one object.

it also isn’t intended to produce film grain. the grain is only seen on surfaces, and if your sampling is low.

last but not least - while real photographers/film makers tend to avoid grain/blur etc. to a certain extent,3D artists try to fake it for the ultimate realism - simply because the eye is used to look at real film, which in any case has imperfections. common 3D graphics tend to be too perfect and clean, so that the human brain doesn’t accept them as “real”- (which is ok if they aren’t meant to be photo-realistic)

Can you use AO to get more realistic soft shadows? I tried the tutorial in the manual where you duplivert a bunch of spotlights with the goal of making shadows that are sharp at the base and blurry further away. Unfortunately all I ended up with was a whole bunch of individual shadows. Instead of looking like a big sun shining down, it looked like a whole bunch of tiny suns shining down, made all the worse by the dozens of specular reflections from all the ‘suns’ I had in my ‘sky’. So my picture went from looking unrealistic to looking even-more-unrealistic.

Ugh, all my attempts look nothing like the nice pictures here.

Then it takes a terribly long time to render.

Then it takes a terribly long time to render.[/quote]

More quality = long time to render. :wink:

If you look at a candle in real life, you see a tall white stick with a yellow flame on top - but if you look at a photo of a candle you see a tall white stick with a white blot on top, possibly with lines sticking out of it, and maybe even a multicoloured lens flare if the candle is bright enough.

Since you’ve seen both of these all the time, you see both of them as “real” and “normal”, but if you were to see a candle in real life with an overexposed flame and lens flare you’d definatly not think it was real!
In the same way, if you were to see a normal candle with a yellow flame in a photo you’d think it was fake.

When you see a CGI render, the brain thinks it’s a photo, not a real object - so to convince the brain that it’s real and not faked, you have to make it look not real, but like a photo of a real object.

This means faking flares, focal blur, motion blur, etc - even though they make it look less like reality, they make it look more “real”.

So we have realism, making something look real, and photorealism, making it look like a photo of something real.

I did that too. It happens when you don’t have enough spotlights. It’s the same in the GI hemisphere bit where you use dupliverts and an icosphere to do GI. With a level 2 icosphere you see all the overlapping lines but on level 3, they disappear.

In your case, just physically subdivide your mesh i.e. don’t use the subdiv levels because that won’t work. Possibly widen the angle of your light too - that way more lights interfere.

Thanks. I guess the reason I didn’t do more points on my icosphere was because of the extremely long rendering time it was taking. I had a higher level icosphere but it was taking so long to render that I just pressed escape right away and changed it back to 2. Then later on I never thought to change it back to level 3+.

I guess another skill I will have to develop here is patience, heheh.