Che from Turn10 studios has made the statement that motion blur at 60fps isn't necessary. This statement was made due to the decision by Turn10 to disable motion blur in Forza Motorsport 2 (a previously announced graphical feature).Some visitors are having a difficult time understanding why this is incorrect due to the common mantra about 60fps being "all the eye can detect". While this isn't totally true (a typical eye can detect refresh changes in the 72Hz range, and some eyes much higher) lets assume that the typical eye cannot detect frequency changes above 60Hz.

The first major point is that refresh rate tells us very little about the rate of animation. e.g. You could capture a football player running at 24 frames per second and display that on a 60Hz display and the 24fps running motion would appear jerky--even though the monitor is refreshing faster than the eye can detect.

Further, it must be remebered that a display rendering a 3D scene has to first overcome the obsticle of recreating 3D space and spatial motion on a 2D imobile screen. Second, a display must also adapt to the fact that objects can move across the screen ("animate") so fast that the rendered output, even at 60Hz, is missing significant gaps in animation substance.

The below graph represents 2 scenarios.

Scenario #1: No motion blur. 60Hz on a 720p display. The numbered columns represent a 1280 wide screen broken up to 60 columns, each consisting of about 21.3 pixels. The first frame (1/60) is the beginning frame, and the second frame (2/60) is the ending frame; in Frame1 the object is still and in Frame2 the object has moved to its new point.

Note that while the refresh rate is 60Hz, the object itself has bypassed 9 columns during 1/60th of a second. The display without motion blur doesn't represent or compensate for the missing information. The ball appears to teleport from one point to the next. Extrapolating this across 6 frames (1/10th of a second) the ball will blip, or teleport, to 6 points across the screen and disappear.

Scenario #2: Motion Blur; 60Hz on a 720p display. The numbered columns represent a 1280 wide screen broken up to 60 columns, each consisting of about 21.3 pixels. The first frame (1/60) is the beginning frame, and the second frame (2/60) is the ending frame; in Frame1 the object is still and in Frame2 the object has moved--and the data "lost" between screen refreshes has been similated.

Much like a camera or the human eye, data that could not be clearly captured in the refresh period has been simulated with blur, representing the movement data that is missing.

This is akin to taking a picture (with a 1/60th shutter speed) through a window as a ball passes by. Although it may be passing by at a high rate of speed greater than 1/60th second for the small window, the camera would detect the motion and record a "blur" in the picture.



While increased game framerate and display refresh rate will decrease this issue (120>60>30>15), for a 1280x720 display to completely resolve the lack of source material it would need to render at 1280fps with a 1280Hz refresh rate to account for fast moving horizontal objects. There is a point of diminishing returns, but as the graph illustrates, an object moving at 210 pixels horizontally per frame will cross the screen in 1/10th of a second and teleport 6 times. Putting this in the context of a display 36" wide, that would mean the object moves 6 inches per frame and has NO intermediate data between points.

Ps- I should point out the pictures of Che playing on a 3 system / 3 display setup actually demonstrates the importance of motion blur. By wrapping the displays to the perephrial vision, where the eyes daylight viewing rods and cones are far less dense, Che is getting an excellent perception of motion blur because the human eye isn't capable of sensing the same degree of clarity on the perephrial portions of vision. While not a substitute for motion blur, having the fastest moving objects (i.e. objects to the right and left move MUCH faster in screen space than objects in the far distance dead ahead) this sort of setup allows for a nice sense of motion blur due to the nature of the eye itself.

The Xbox, PS2, and GCN did use some crude motion blurring tricks in some games (interestingly MKDD!! even used DOF!). I haven't played GT3 in many years so I couldn't comment on that.

By teleporting it means the object just "moves" from one spot on the screen to the next. Imagine this: there is a UFO hovering on the far left of you 42" Plasma, and in 2 frames period of time it moves and stop on the far right side of your 42" Plasma. Without motion blur the UFO will do this:

Frame1: On the far left
Frame2: In the middle
Frame3: On the far right

ALL the movement data from left to center to right has been lost because it didn't appear in the render frame "snaptshot". When Frame2 "snapped" the object, it was in the middle.

Yet with a video film camera (like movies and TV use, as well as typical cameras taking consecutive shots with a 1/60th exposure time) you would see the UFO in the middle of Frame2, but the difference being that you would also see "streaks" of motion.

Why?

Just divide the time between Frame1 and Frame2 by 10. The UFO spends equal time in each of those 10 frame segments during the exposure time.

That is why it is technically inaccurate to render the frame without rendering the calculated velocity (motion blur).I know people who cannot see the difference with 30fps, does that mean it every game should be 30fps? Typically once you SEE an effect (e.g. 60fps with Motion Blur) and then see the same game or style of game without the effect it takes hold.

Depth of Field, Motion Blur, HDRL, and so forth are techniques to simulate how the eye works in a 3D world in a 2D screen. Displays don't have light intensity, so they simulate HDRL through biasing light and bloom to react how your eye would. Displays don't have depth, they are 2D, so DOF simulates the effect of looking at an object and non-focused objects looking hazy. And Motion Blur accounts for the disparity of displays with limited refresh rates not representing missing motion that film and the eye would naturally pick up (because we all know that an object doesn't move 6 inches instantaneous between frames but gradually moves throughout the frame transition, see animation tweening).

If Motion Blur is useless at 60fps it is nearly as useless at 30fps for the reason motion blur is compensating not only for the limitations of display frequency but as well as RENDER frequency.Developers make errors all the time! Developers also meet deadlines, budget limits, and hardware limits all the time as well.

The fact FM2 dropped from 12 cars to 8 cars is almost certainly due to performance. Would the game be better with more cars? Seeing as they spent over a year -- maybe 18 months -- designing their game with 12 cars at a time in mind it surely seems it was the goal and design plan.

It could use a crude form of motion blur, but it may / may not look very good. Like HDR, there is not "real" motion blur on current displays. Sure, a SEDs display could do a rough comparison to real HDR, and a 600Hz display and a game rendering at 600fp would do a pretty good job of doing motion blur. But as it stands now we are just using various techniques that do a good job of faking it. With HDR we use Iris effects, tone mapping, and bloom to simulate what the effect of HDR would be on a still image. With motion blur you can use basic vector math, velocity maps (which use the depth buffer and post processing of the framebuffer to distort the framebuffer), or accumulation buffers. i.e. There is no such thing as "real" motion blur on current displays -- just better and worse techniques.I see a lot of Che bashing.

To make it clear: Che didn't release the 12 car, 18 track, motion blur, etc PR. That was the Turn10 development leader, Dan Greenawalt.

Further, Che is a MS employee. Almost everything he says passed through PR first and he is TOLD what to say. That is his job.He has been told by his bosses to strategically break information, both positive and negative, in the fashion his bosses desire. He would be instantly fired if he made a comment like, "8 cars" or "No motion blur" if his bosses did NOT direct this information.

Why do you think he says he has info for Friday and then turns around and says "maybe next week"? It is because he was told to tell people it was coming, and THEN told it wouldn't be and HE had to tell everyone. If he was a loose cannon he would just leak the juicy stuff.Every game without motion blur (and even with in many cases) has "teleporting" when an object quickly moves across the screen. It is a reality and limitation of technology.If you get into a fast tailspin where you are doing 360s every .5 seconds, your screen space will progress 12 degrees every frame at 60fps. Assuming a 90 degree field of view, an object that enters the screen on the left as you spin will be on the screen for 7.5 total frames before it exits on the right as you spin. This means the object is moving 170 pixels per frame from left-to-right. Lets say your TV is 42 inches wide, that means the object is moving over 5 inches per frame with no intermediate data.

170 pixels, 5 inches, 12 degrees.This isn't an issue of whether people can enjoy the game--I have said many times I expect FM2 to be a good game. I also quite enjoyed CBFD on the N64 and it had horrible framerate issues in MP.

The issue isn't whether FM2 or other games are bad games.

The issue is downplaying a feature (your formerly bragged on!) as well as misinforming the public about the technical aspects of said feature.

I have spent a bit of time defunking inaccurate and misleading information about RSX, Xenos, Cell, and Xenon in the past. Op you are aware that I spent a lot of time disecting the E3 2005 PR about "2x faster" and what not that Sony slides had and thus far the games on the market have proven me right: The Xbox 360 GPU isn't half RSX, but in many cases can be even faster.

So this is no axe to grind or effort to defend one platform over another. It is simply my continued goal to cut through FUD and present fair, objective discussion on a matter. If I am wrong I am wrong -- but not because I am taking up the Xbox Evangelizing cause or have been bought out by Sony.

I haven't been following the game hardly at all. I do know they are using some very convincing volumetric lighting though that gives a great effect at the speeds the cars travel that cannot be conveyed well in screenshots. The last video I saw of F1 was in the summer and I haven't read a thing about it since. Sorry Ken. History says the F1 series is average, but I am hoping next gen reinvigorates the franchise and the devs get a new chance to show what they are made of.

I thought the following post from another forum would be helpful to those who still are confused about the need for motion blur to aid object velocity

-------------------------------------------Two issues: Display refresh rate versus object velocity.

I can notice the difference between 30fps and 60fps. Even games that overage over 100fps on my display (75Hz) and Vsync enabled I can detect some hitching when their are minor drops (e.g. BF1942 with a 6800GT is capped at 100fps and mainly stays there but may see very, very short dips). Tearing bothers me much more than 30fps, and an unstable high framerate than a lower locked one.

So I can "see" a display refresh rate difference, and the impact it has on fluidity, but I am not as sensative to it as I am to other factors. In most games it doesn't impact my gaming experience much.

But I think the "60fps solves all problems" mantra (currently being pushed by Turn10) is very misleading and confuses the display refresh rate (and the associated fluidity of the screen) with object velocity -- two very different problems.

60fps may be substantial enough for your eyes to resolve all motion velocity issues, but I must say not for mine. Not even close. See the following attachement for an example of the issue imo:



A1 / Frame1: The Ball is not on screen.
A2 / Frame2: The Ball has entered the screen space about 50 pixels.
A3 / Frame3: The ball, in 1 frame's time the ball has moved nearly 1000 pixels from left to right.

B1 / Frame1: The Ball is not on screen.
B2 / Frame2: The Ball has entered the screen space about 50 pixels with associated blur due to motion.
B3 / Frame3: The ball, in 1 frame's time the ball has moved nearly 1000 pixels from left to right. Not that motion blur is present expression the object velocity and motion during the duration of the 1/60th exposure.

In Example A, the problem is that the object blips across the screen. It is impossible for your eye to compensate for the missing motion (as a camera or the eye would) because there is no data for the eye to interpolate. As far as they eye would be concerned in this scenario it is just a circular object (UFO?) popping up on the screen for 2 frames and dissappearing. Little, if any, sense of motion is conveyed.

In Example B, the object's velocity is considered. The ball is moving at a very high rate of speed and during the 1/60th exposure of the frame the places the ball was during the frame are represented.

And that is the difference: Example A (60fps without motion blur) treats moving objects as if they appear at static, singular positions during the frame.

In Example B, which is more realistic, an object is expressed as its placement during the entire exposure and not as an arbitrary point.

Now this is an extreme example, but there are similar conditions you will see in a racing game. A fast turn will see the gamers field of view change very quickly, and a spin out could see > 10 degrees (over 150pixels) of change in the centerpoint on a 720p display (about 4 frames from center to off screen). And most commonly are objects on the perephrial portion of your field of view. While driving down a straight away at 200MPH objects in the center of the display and at a great distance away have very little relative movement on the screen. But objects on the far right and left of the display are moving EXTREMELY fast as they pass by. And object 25% from the far left or right in Frame1 may not even be on Frame2 due to the speed of the car.

So what Che/Turn10 has said, that at 60fps there is no need for motion blur because 60fps recreates all the blur, is not true at all.

YMMV with your eyes and what you are comparing/contrasting it to. Granted a lot of racing fans have yet to see a 60fps racer with "propper" motion blur so it is hard to get excited about it. But there is a reason why Bizzare and Turn10 were both aiming for 60fps AND Motion Blur.

It seems both feel short, one on 30fps with and the other 60fps without.True, just like any other artistic effect (HDR and Bloom, Lense Flares, Reflections, etc) they can be illconceived, misapplied, a poor technologically implimentation, or just artistically lacking. I do think BC's motion blur in PGR3 was well balanced and don't see why Turn10 couldn't have gotten some advance from them.I obviously won't argue with your eyes! But they are not mine.

And I would say that statements like, "All I know is, at 60 fps, motion blur is not needed and wouldn't enhance the smoothness much (if at all)" sound very, very similar to the:

"All I know is, at 30fps, the game is smooth and 60fps is not needed and wouldn't enhance the smoothness much (if at all)".

And while this is my opinion, I am a very firm hunch that by the Xbox3/PS4 gamers will be demanding motion blur at 60fps for an improved sense of motion. 30fps with, and 60fps without, won't match up to the graphic-centric "desire". Of course the portion of the market demanding such is small, likewise the segment demanding 60fps. In the FM2 case there is no game pushing them to this standard. Once a technically solid racer appears that does both I think people will be more inclined to demand both. IMO of course (as what people what/demand, well, is hard to gauge... Wii?)Motion blur isn't necessary by any stretch, neither 60fps. A game stands on a collection of merits.

For me it is a selling point. FM2 is one of the games I have been looking forward to and might compell me to a purchase. The PR handeling of FM2 is pretty poor, especially the delay+significantly cut content and features.

On the other hand I think their rebalance of the lighting, toning down of the HDR, and toning down of the reflections has done a TON for the graphics. Right now graphically it looks fine to me (a good next gen racing game... ableit I will wait to see it in motion to make my final judgement!) So I am not dogging FM2, I am mildly surprised at the progress they have made. But I am annoyed that they market a laundry list of features... and then fail to deliver on many.

And even more annoying when they make factually incorrect statements to sick on the "haters" as Che keeps saying.

Reading comprehension. The point is a technical one and discrediting yet another example of MS/Sony FUD that they heave on gamers and they dutifully spread their FUD.

In regards to this thread the point isn't whether FM2 will have it, but the question: Is it needed? Isn't 60fps all we need? And the facts are a resounding no, this isn't true.

You can discuss FM2 in the other thread (which I left to post here because some posters a. don't seem to comprehend certain points being made and b. a clean thread devoted to a single technical issue wouldn't get lost, or detract, from the discussion).

At the end of the day 60fps doesn't resolve object velocity viewed on screen, and that is the point of this thread.

Exactly my point.

You came in here, without fully reading what was written, misunderstood the discussion, went off topic and were "telling me how it is" without even comprehending the point of the thread and engaging the thread discussion.Hence you need to reread the thread (or read it for the first time) because this isn't a plea to some developer to add a feature. It is a technical discussion about motion blur and why 60fps render and refresh rate do not resolve motion compensation issues for fast moving objects.

Your comments about Turn10 are off topic, and telling me to "get over it" is very much out of line as this is the correct forum to be discussing technology and whether PR-tech speak is accurate or not.And the technical forum is here to allow those with insight to explain technical matters, explaining the merits -- or lack thereof -- of the marketing people's PR for those who are interested in the topics. The fact of the matter is some of us like discerning the facts instead of being sheeple, "ZOMG! RSX has 60% shader opps per cycle and 200% bandwidth!"

This forum is here to answer those very questions, and be a repository of information so when these questions come up again they don't need to be debated endlessly.Please don't tell me how I am being rude for telling you to go reread the thread because this statement absolutely confirms you didn't read (or read and didn't comprehend, or skimmed without comprehending, etc) that point.

Pointedly: 60fps will not give you fluid motion in regards to objects moving at a high rate of speed across a display.

Fact. End of story.

If you disagree with this fact, you can start by reading the following points and explaining why it is technically incorrect:This is a clear example of how 60fps isn't "fluid motion" as you incorrectly suggest. As an aside, the choice isn't "MB or 60fps" as you can have both, they are not incompatible technologies.