Ambient Occlusion by Mike Blackney
Rawn (RawArt)
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Ambient Occlusion by Mike Blackney http://www.filterforge.com/filters/4517.html  |
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| Posted: October 10, 2007 5:34 am | ||||
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Rawn (RawArt)
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This one could be very useful...I can't wait to try it out.
Do you have any samples of this in use? Rawn |
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| Posted: October 10, 2007 5:35 am | ||||
Mike Blackney
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Sure thing  Here's a brick texture: |
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| Posted: October 10, 2007 7:48 am | ||||
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Mike Blackney
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And a kinda wood panel texture: |
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| Posted: October 10, 2007 7:48 am | ||||
| Kraellin |
mike, uhm, i think this is good, but i cant really tell. i tried to look up 'ambient occlusion' and almost went to sleep. it seems to be one of those terms that when you look it up you have to look up 20 other things just to understand the first one. lol. so, about all i could tell about it was that it has something to do with lighting, especially lighting of the normal map (which i dont really fully understand either), which in turn supposedly gives a better lighting model/result. Ya can't sell art to artists!
Craig |
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| Posted: October 10, 2007 8:06 am | ||||
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Mike Blackney
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Heh yeah it is one of those terms. I think it's probably intentionally obsure so that only the pros will do it, or something.  Occlusion just means 'to hide' and the ambient is talking about ambient light. So it really means, 'hide from ambient light' and it's used when talking about pit and crevasse shadowing.
Everywhere that there's a crack, pit or dimple on a surface, the pit is shadowed because the only light that can reach the deepest part of the pit to reflect back is light from directly overhead. This means that all the ambient light (which is light that bounces around the atmosphere and off other objects, rather than direct light coming straight from a light source) tends not to reflect and pits look darker. Here's a great primer with images of why you might want AO in game texturing: http://www.gamasutra.com/features/20040319/hill_pfv.htm I hope that's understandable...  |
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| Posted: October 10, 2007 8:18 am | ||||
| Kraellin |
ok, i get the idea of it if not the exactness of it. it's basically, then, just a way of doing better shading/shadowing based primarily on an adjustment of the normal map using another array or mapping onto the normal map... i think. Ya can't sell art to artists!
Craig |
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| Posted: October 10, 2007 8:30 am | ||||
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Mike Blackney
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Yeah, except that until recently more often than not people have rendered out ambient occlusion using their rendering app and taking a good ten minutes for a high-quality version. Using the normal to make an AO map is reasonably new and since CrazyBump recently started offering it I figured FF could do it no sweat   |
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| Posted: October 10, 2007 8:38 am | ||||
| Kraellin |
i'll take your word on it (not being a 3d person, myself...yet) Ya can't sell art to artists!
Craig |
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| Posted: October 10, 2007 9:03 am | ||||
Carl
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Very clever filter [ like all your filters ] and interesting about lighting - had a look at your web site very impressive - one comment though veiwing your site [ using IE 7 ] the sub-heads in a number of places partially overlays the text above making them almost illegiable I'm going to live forever or die trying
........Carl |
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| Posted: October 11, 2007 2:18 am | ||||
| Nic74 |
LoL I started to work on an AO filter couple of days ago based on crazybump too:-D You did a good job but I would like to have some control over the levels. Usually you dont want the gray middle tones (not all pictures is high contrast like the default picture ).
I got overboard with my filter. It started like an AO, but I wanted all in one and made old dirt look and now its to messy and to publish. The AO effect is basicly created with highpass and multiply in my case... if you want you can check out a preview. http://www.filterforge.com/forum/read.php?FID=14&TID=4118 |
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| Posted: October 11, 2007 10:30 am | ||||
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onyXMaster
Posts: 347 |
We have a working AO implementation stashed
It could use some support for bent normals for even more realistic lighting, along with proper handling of seamless (ray wraping) and non-seamless (range limitation) cases. But most importantly, it needs a new rendering UI logic, since it's slow as hell for the first block due to the amount of precalculations needed, but then it gets faster and faster -- might be some sort of a cached data which has some kind of "precalc" progress bar, with intermittent storage much alike the relighting scheme that was recently discussed in a neighboring thread. |
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| Posted: October 11, 2007 12:18 pm | ||||
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onyXMaster
Posts: 347 |
By "working AO" I mean _real_ diffuse lighting AO with random sampling, controllable noise level and stuff, not edge detection-based tricks like the high pass mentioned above
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| Posted: October 11, 2007 12:20 pm | ||||
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onyXMaster
Posts: 347 |
Note: Above posts do not imply that this code will be released in _any_ future versions. Currently, it's "not ready for production". | |||
| Posted: October 11, 2007 12:22 pm | ||||
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onyXMaster
Posts: 347 |
A small example of AO.
Surface without AO: 
Surface with AO:  |
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| Posted: October 11, 2007 1:06 pm | ||||
StevieJ
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The shadows look much nicer, but the highs look depleted.....probably because of the plateaus in the sample.....would like to see it on a sphere..... Steve
“Buzzards gotta eat.....same as worms....." - Clint :) |
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| Posted: October 11, 2007 1:15 pm | ||||
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onyXMaster
Posts: 347 |
Yes, the plateaus are the problem here -- any flat surface that is close to horizontal orientation works like a mirror
4 "compressed spheres" (i.e. a half of a sphere with surface Height set to 25) with AO:  |
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| Posted: October 11, 2007 1:25 pm | ||||
| Kraellin |
i also notice on this last, something i've seen when working with the noise components... lighting doesnt just re-light or re-shadow or highlight or diminish, it also is changing the basic shapes and forms at times, or at least the 'apparent' shapes and forms. i would think this would be something to avoid in a true lighting scheme. it's kind of cool in an artistic view, but for true lighting, particularly in 3d environment, i'm not so sure it's desirable.
p.s. when i said 'last' here, i was referring to the stones images, not the spheres. that spheres one was posted while i was writing. Ya can't sell art to artists!
Craig |
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| Posted: October 11, 2007 1:29 pm | ||||
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onyXMaster
Posts: 347 |
I don't think that I get what you're talking about, Craig -- how lighting should _not_ change the form? | |||
| Posted: October 11, 2007 1:34 pm | ||||
| Kraellin |
onyx, look at the two stones images you posted. they are not exactly the same in form any more. the lighting actually changed the shapes in places. you can tell they are the same image because mostly the forms of the two line up exactly, but not everywhere. do a side by side comparison and you'll see what i mean. or better, do them in layers and with a lowered opacity settign on the top one. Ya can't sell art to artists!
Craig |
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| Posted: October 11, 2007 1:51 pm | ||||
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onyXMaster
Posts: 347 |
Ah, _that_ one
Well, AO vs flat lighting _must_ change the result, shouldn't it? |
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| Posted: October 11, 2007 2:52 pm | ||||
| Kraellin |
hehe, well, i suppose if you changed everything to white or everything to black, the form/shape of the image would change Ya can't sell art to artists!
Craig |
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| Posted: October 11, 2007 3:30 pm | ||||
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Mike Blackney
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onyXMaster: Wow, AO in a future version would be just awesome! I can imagine it'd be a lot easier to make realistic textures.
Nic74: You're right, the AO for photos was rushed. This filter is really built to be used on normal maps firstly, and support for other images I put in to make sure that the default preset looked like ambient occlusion I had a look at your version and holy smoke it looks neat. Please submit it!
Karl: Thanks!, and thanks for the tip on my website. I'll get onto that! |
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| Posted: October 11, 2007 9:46 pm | ||||