New DoF and Motion Blur Technology

wuliheron

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Feb 8, 2011
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http://www.sciencedaily.com/releases/2011/06/110613113850.htm

ScienceDaily (June 13, 2011) — Photographs of moving objects are almost always a little blurry -- or a lot blurry, if the objects are moving rapidly enough. To make their work look as much like conventional film as possible, game and movie animators try to reproduce this blur. But counterintuitively, producing blurry images is actually more computationally complex than producing perfectly sharp ones.

In August, at this year's Siggraph conference -- the premier computer-graphics conference -- researchers from the Computer Graphics Group at MIT's Computer Science and Artificial Intelligence Laboratory will present a pair of papers that describe new techniques for computing blur much more efficiently. The result could be more convincing video games and frames of digital video that take minutes rather than hours to render....

...In that paper, the researchers make the simplifying assumption that the way in which light reflects off a moving object doesn't change over the course of a single frame. For each pixel in the final image, their algorithm still averages the colors of multiple points on objects' surfaces, but it calculates those colors only once. The researchers found a way to represent the relationship between the color calculations and the shapes of the associated objects as entries in a table. For each pixel in the final image, the algorithm simply looks up the corresponding values in the table. That drastically simplifies the calculation but has little effect on the final image.

Adopting the researchers' proposal would require modifying the architecture of graphics chips. "You can imagine really just going ahead and building what they suggest," says Henry Moreton, a distinguished engineer at Nvidia. "But I think that the greater value of the paper is that it points at strategies for solving these problems more elegantly, more efficiently, and more practically. Whether they manifest themselves in exactly the fashion that the paper presents is probably not that likely. But what they did is they pointed to a new way of attacking the problem."

Turning the tables
The second of the Computer Graphics Group's Siggraph papers, led by Lehtinen and also featuring Durand, Chen and two of Lehtinen's Nvidia colleagues, reduces the computational burden of determining which rays of light would reach an imagined lens. To produce convincing motion blur, digital animators might ordinarily consider the contributions that more than 100 discrete points on the surfaces of moving objects make to the color value of a single pixel. Lehtinen and his colleagues' algorithm instead looks at a smaller number of points -- maybe 16 or so -- and makes an educated guess about the color values of the points in between. The result: A frame of digital video that would ordinarily take about an hour to render might instead take about 10 minutes.

In fact, both techniques apply not only to motion blur but also to the type of blur that occurs in, say, the background of an image when the camera is focused on an object in the foreground. That, too, is something that animators seek to reproduce. "Where the director and the cinematographer choose to focus the lens, it directs your attention when you're looking at the picture in subtle ways," Lehtinen says. If an animated film has no such lapses in focus, "there's just something wrong with it," Lehtinen says. "It doesn't look like a movie." Indeed, Lehtinen says, even though the paper has yet to be presented, several major special-effects companies have already contacted the researchers about the work.
 

wuliheron

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Anyone who has tried the currently available DoF in games like metro 2033 knows it can cut your fps in half and isn't all that great looking. Likewise some people just can't stand the motion blur in games like Crysis. With all the lighting effects and whatnot available now this is the final touch needed to create truly cinematic quality video games.
 
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GoodRevrnd

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I don't get the fascination with motion blur. If a truck goes whizzing by you at 40mph, it isn't blurry, your eyes just have trouble focusing on it. It's the same thing in games, the object should just move across the screen quickly and that will provide the difficulty in seeing. Blur is just another level of shit piled on that may be interesting cinematically but is flat out detrimental to gameplay in my opinion (especially FPSs). I'm trying to play a game, not watch a movie.
 

buzzsaw13

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motion blur is the worst thing to come to FPSs for me. I can't play any new shooters because they all have this garbage that makes me want to throw up after playing for 20 minutes
 

wuliheron

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I don't get the fascination with motion blur. If a truck goes whizzing by you at 40mph, it isn't blurry, your eyes just have trouble focusing on it. It's the same thing in games, the object should just move across the screen quickly and that will provide the difficulty in seeing. Blur is just another level of shit piled on that may be interesting cinematically but is flat out detrimental to gameplay in my opinion (especially FPSs). I'm trying to play a game, not watch a movie.

They're called "video" games for a reason. They are movies and some are just less abstract cartoons then others. The problem is games would have to produce something like 300 fps to simulate that truck passing you. With graphically demanding games like Crysis that can cripple computers they wanted people to be able to play it at 30 fps without it looking like an old herky-jerky silent film or bad claymation.

Perhaps if they make serious improvements to the technique you'll find it more agreeable.
 

StinkyPinky

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First thing I do in a modern game is turn off motion blur. Looks like shit and I don't understand how anyone can like it.
 

Markbnj

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I don't get the fascination with motion blur. If a truck goes whizzing by you at 40mph, it isn't blurry, your eyes just have trouble focusing on it.

Well, that is just the definition of "blurry". We're not talking about fog effects. The effect is created by the limitations of our visual sense. It's not just focus. The retina in your eye has a "frame rate" for lack of the proper term. It retains ghosts of previous images, and can only send information about new images to the brain at such and such a rate. So something moving very rapidly through the field of view looks blurry.
 

MTDEW

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Me personally, i was referring to the blur they implement when you turn your head, everything blurs as you turn.
I turn that "feature" off immediately whether im getting 100fps+ or not, cuz its annoying.

Now DOF (Depth Of Field) is just fine if its done right and not used to mask a poor draw distance.
ie: Things in the DISTANCE can blur some to create the DOF effect, but when the blur effect starts like 100yds from your character it looks unrealistic.
 

smackababy

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New motion blur technology: people realized that when you run, things don't get all blurry! That is a feature I want in an action game.
 

GoodRevrnd

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Well, that is just the definition of "blurry". We're not talking about fog effects. The effect is created by the limitations of our visual sense. It's not just focus. The retina in your eye has a "frame rate" for lack of the proper term. It retains ghosts of previous images, and can only send information about new images to the brain at such and such a rate. So something moving very rapidly through the field of view looks blurry.

Exactly. Because your eye does this on its own you don't need a video game "doubling up" on the effect making things impossible to see. Not to mention when they do it, it's always grossly exaggerated, and like another poster mentioned the turn your head blur is flat out awful.
 

supremor

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I also don't get this fascination with motion blur or DoF for that matter. I get that its supposed to make the game more cinematic and realistic or whatnot but they seem to put these features mostly in FPS games and I just find myself asking why would you even want things out of focus to be blurred and fast moving objects to be blurry? I know I like to have a nice clear view of my surroundings at all times whether I'm aiming down the sights or looking at fast moving objects. Needless to say I always turn off crap like motion blur and DoF.
 

Dankk

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Motion blur can be good, when used correctly. Portal is a good example. You don't even notice it's there, unless you're being launched at extremely high speeds, and even then you STILL don't notice it because it's implemented very tastefully. It adds to the feeling of flying around, but it's not obvious enough that it's shoved down your throat.

I remember playing the Crysis 2 demo though, and it was like "HOLY SHIT, LOOK, IT'S MOTION BLUR, MOTION BLUR ALL THE WAY DOWN." That was an example of how NOT to do motion blur.
 

busydude

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Feb 5, 2010
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The only games which put MotionBlur to good use are DiRT series and F1 from codemasters. Other than that.. I don't know any titles that I enabled that option.
 

imaheadcase

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May 9, 2005
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Motion blur looks bad in lots of games, certain games it has potential to look good it it. I can see horror games making use of it for effect..monsters running past you real fast or something. Maybe other games i can't think of.

I just thing devs think they need to use it in every game.

But opinions are just that, i think AA is useless in games so disable that first thing.
 

DeadFred

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Jun 4, 2011
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First thing I do in a modern game is turn off motion blur. Looks like shit and I don't understand how anyone can like it.
same here

Crysis 2 holds the blur crown atm but it looks as though BF3 is gonna try to take it away.
 

Bill Brasky

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Motion blur can be good, when used correctly. Portal is a good example. You don't even notice it's there, unless you're being launched at extremely high speeds, and even then you STILL don't notice it because it's implemented very tastefully. It adds to the feeling of flying around, but it's not obvious enough that it's shoved down your throat.

I remember playing the Crysis 2 demo though, and it was like "HOLY SHIT, LOOK, IT'S MOTION BLUR, MOTION BLUR ALL THE WAY DOWN." That was an example of how NOT to do motion blur.

This is a great example, and you're right; most people don't even notice it WHICH IS THE POINT. Motion blur is supposed to help immerse the player further into the game, not detract from it.
 

wuliheron

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Feb 8, 2011
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This is a great example, and you're right; most people don't even notice it WHICH IS THE POINT. Motion blur is supposed to help immerse the player further into the game, not detract from it.

Exactly. Motion blur is usually not supposed to be noticeable anymore then the makeup hiding the zits on your favorite actress's face. Occasionally it might be used to create a carnival ride special effect, but right now the big problem is how to use it subtly to simply hide the inherent flaws of the technology.
 

destrekor

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Exactly. Because your eye does this on its own you don't need a video game "doubling up" on the effect making things impossible to see. Not to mention when they do it, it's always grossly exaggerated, and like another poster mentioned the turn your head blur is flat out awful.

Way too much visual information is completely absent, and thus the effect can not be naturally produced on a small screen.
There is no real depth, the information cannot be delivered to our eyes in the way our eyes process information (our eyes are constant, yet with a frame-rate of sorts... displays are refresh-based, not a constant stream of photons).

Yes, in real life, we have natural motion blur.
The reason it is artificially produced in video mediums is because of the fact that natural motion blur CANNOT happen due to the restraints of the display system.

FOV, DOF, refresh rate, radiation, and additionally the fact that far more of this information is presented closer to our true center of vision.

There are too many variables that current display technology cannot reproduce, and so our eyes cannot be perfectly tricked. And thus, until our methods of drawing images on a display is revolutionized, we'll have to use artificial means to reproduce the effect.
 

MTDEW

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Oct 31, 1999
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Reading all the replies here, where the majority hate the features and turn them off anyway, yet they are still added to games even though we dont want them shows just how much developers dont really listen to gamers opinions anyway.

I mean, we've all been trying to get them to stop adding an autosave before a long cutscene just before a big boss fight since i can remember, and they STILL do it.
So you have to reload and watch the same cutscene over and over.

In other words..... Why do we even need new DOF and Motion Blur tech when nobody wants it in the first place?
 

Emultra

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Jul 6, 2002
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I always turn motion blur off. Looks and feels better, and saves performance as well. It's a solution to a problem that doesn't exist.