The Great Simulated Optics Debate *spawn

@sebbbi

Ok that motion blur would require eye tracking to be applied truly realistically/correctly, it was said before and I got it, but I don't think that for this reason it should be removed/eradicated from games.
Motion blur even if applied approximately can still be useful/helpful.
Do you agree or disagree?
What's you opinion as a developer on this?
 
The area where motion blur is applied depends on where the player is looking at so yeah, you need eye tracking.

If you're looking at something that isn't moving there is no blur regardless of where you're looking. It only blurs if you're focusing in/out or if you don't have good clear vision.

Motion blur refers to things in motion...;)

Now if you're talking about motion blur produced by fast movement of the eyes then that is a different issue...
 
If you're looking at something that isn't moving there is no blur regardless of where you're looking. It only blurs if you're focusing in/out or if you don't have good clear vision.

Motion blur refers to things in motion...;)
When tracking an object, any other object on a different motion vector will exhibit motion blur. If you are following a car in a racing game, the crowd behind will be heavily blurred. This can only be realistically created in current games by selectively blurring the crowd - 60 fps is not fast enough to generate natural motion blur - and of course seeing whether the player is looking at the car or the crowd is essential to know where to apply the moblur.
 
When tracking an object, any other object on a different motion vector will exhibit motion blur. If you are following a car in a racing game, the crowd behind will be heavily blurred. This can only be realistically created in current games by selectively blurring the crowd

Of course..

60 fps is not fast enough to generate natural motion blur

And where did you get this information from?

and of course seeing whether the player is looking at the car or the crowd is essential to know where to apply the moblur.

Um what? As I said it doesn't matter where you look ie if an object is static which in your example it's the car there is no blur and if an object is moving in the background there is blur. If a tree falls does it matter if you saw it fall or not? No...it still fell regardless...

Sooo....you still blur the stuff that moves regardless whether or not the person's eyes are looking at it. Why is this so hard to understand? Are you trying to save processing power or something? :LOL:
 
"If a tree falls in a forest and no one is around to see it, is there motion blur?"

If the forest was in a game you blur it regardless if there's anyone around to see it...because if the game is running then somebody turned on the console and is playing the game...and because you can't predict where they're looking at any given moment when no eye tracking is involved.. ;)
 
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^^^
Alas you didn't appreciate the paraphrase :(

BTW, if technically possible, employing MB only when the camera it's looking could be a better choice than apply it at all times.
Since eye-tracking it's not used why no use camera-tracking!?

EDIT

Maybe I am talking nonsense but it would be nice to be wrong anyway :)
 
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And where did you get this information from?
Playing games at 60 fps with strobing motion. Fast movement (determined by screen size, viewing distance, and angular velocity across the FOV) isn't smooth at 60 fps.

Um what? As I said it doesn't matter where you look ie if an object is static which in your example it's the car there is no blur and if an object is moving in the background there is blur.
If you are looking at the car, you need to blur the crowd. If you are looking at the crowd, you need to blur the car.

Sooo....you still blur the stuff that moves regardless whether or not the person's eyes are looking at it.
Yes. It's still perceived even if in the peripheral vision.
 
I know in real life we don't have havoc physics (we do have physics, but not the simplified-havoc version of course), but imagine if you have something exploding, sending a box, undamaged, bouncing in a room, spinning on it's Y-axis, in typical havoc physics fashion > if this we to happen in real life then I'm sure that the box would have motion blur as our eyes can only track certain movements.

So that is an example of something that would always have 'motion' blur; even if you tried to track it with your eyes.
 
Games don't simulate what our eyes see, they simulate what a camera sees. People still haven't figured this out after all these years of 3D games?

The only time I've seen the "what your eyes see" discussion come up is in regards to the Oculus Rift, which actually does simulate actual human vision, so devs avoid things like motion blur and lens flare like the plague.
 
Games don't simulate what our eyes see, they simulate what a camera sees. People still haven't figured this out after all these years of 3D games?
They can do both, although I think it's more usual for devs to try to get what's on TV from the console to mimic what's on that TV from other sources.
 
Anybody here ever seen game footage on a Low-Percistance-Display. I guess it is supposes to fool your visual system into not perceiving the strobing of non-MBred footage 60fps mentioned here.
 
Playing games at 60 fps with strobing motion. Fast movement (determined by screen size, viewing distance, and angular velocity across the FOV) isn't smooth at 60 fps.

Define smooth.

But I think I better understand this point of view.

The use of motion blur may be a question of assets that do look too rough, litteraly, because of the limitation of current screens so this cinematic disguise is supposed to erase this flawed motion into something...not rough, something more slick, better, perfectly representing the "idea of next gen title", a perfect, a "pristine motion blur".

But it's not a real (as in crude) motion anymore. It may not be a motion anymore but it's something appropriately better: it's a perfect symbol of a motion.

The artist represents the world into his drawing with its own personnal interpretation of the reality. But the final painting always must be perfect: the artist "adds an extra layer of polish".
 
Define smooth.
A continuous visual representation of the object in motion from one position to another across frames.

Consider pong where the ball can move 1/10th the screen between frames running at 30 fps. When moving it's fastest, it's basically jumping around the screen and the brain can't track continuity. This is basically the problem with low framerate and low temporal resolution making it difficult for the brain to quickly process the scene. If you replace the static ball graphic with a smear from one point to the next as if the ball was being filmed by a camera with 1/30th second shutter speed, it'd be much easier to track what was happening as 1) the ball is easier to find from frame to frame as it's bigger and 2) the trail points the direction vector of the ball so you can predict where it'll end up.

If the display refresh was 1200 fps at the same linear velocity of the ball, no motion blur would be needed as there'd be enough temporal resolution for the eyes to track the object itself. Obviously there'll exist a sweet-spot where refresh speed provides smooth motion for everything that's happening within a game. For slow games, 30 fps is enough. For others, 60 fps is enough, although for some, higher than 60 fps is required. That also depends on how fast things are moving. An FPS with a fast turning rate needs a lot of temporal resolution. Actually that's a good case of where temporal resolution is immaterial. Fixing your eyes front and turning your head, the world is a blur. Exactly the same effect is achieved at 30 fps with a hugely smeary blur effect.

I think a piece of evidence proving the value of motion blur is a still photograph. Where a subject is tracked at speed and the photo taken such that the background exhibits motion blur, we can tell from the static image which direction the object is moving. How? By the direction of the motion blur. Why would a brain be clued up to interpret a directional blur as directional information rather than think something's wrong with the background? Because the brain experienced that itself via the eyes when learning to interpret visual information about the world.
 
If you are looking at the crowd, you need to blur the car.

This is where it gets tricky. When you're driving fast the amount of motion blur in the background should be proportional to the distance the objects are from your viewing position. Stuff on the roadside that are closer to the car will have more blur compared to stuff further from the car. It's analogous to data on the edge of a disc moving faster than data closer to the center. To do realistic blurring you'd need to account for this.

The other part that you describe is a different kind of blur and it's not motion blur. The car isn't moving but since you're focusing on the road side stuff you have "defocused" the car.

So I guess if you want to do realistic simulation of overall blur then you would need eye tracking but if all you wanted to simulate was realistic motion blur from the viewpoint of the camera then you do not need eye tracking.

^^^
Alas you didn't appreciate the paraphrase :(

Actually I thought it was brilliant...:smile:
 
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Shifty Geezer said:
Fixing your eyes front and turning your head, the world is a blur. Exactly the same effect is achieved at 30 fps with a hugely smeary blur effect.
Sort of. 30fps is low enough that you can usually perceive temporal jumps directly regardless of how much MB there is.
This is where it gets tricky. When you're driving fast the amount of motion blur in the background should be proportional to the distance the objects are from your viewing position. Stuff on the roadside that are closer to the car will have more blur compared to stuff further from the car. It's analogous to data on the edge of a disc moving faster than data closer to the center. To do realistic blurring you'd need to account for this.
Adjusting the degree of blur according to distance from camera is extremely common. It's pretty basic actually, fairly obvious if it's not done. Anything less is VERY crude motion estimation.
 
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