ThisNewGuy said:
CrystalShadow said:
That's a partial truth.
But I'd say you need to have a look at that video again. Yes, the remote 'vanishes' between movements, but it reappears again in the same starting spot, primarily because the guy holding it keeps moving his hand to the same spot.
And keep in mind that the the demo at the end was specifically designed to show developers used to the existing Wii dev software that the new system (motionplus) could still do the old stuff, but was more reliable in seperating certain types of movement from eachother.
(notice the last section, where you get things like down. Downleft, Down-right etc. - Is introduced by the statement: 'Livemove 2 can do TRACKING but it can ALSO simultaneously do everything that previous livemove products could do)
In other words, the reason he's demonstrating the stuff at the end it to show that his 'product' (the Livemove dev kit) can still do the old stuff with the new motionplus system, and do it better than the old one could.
The Wii remote (even with motion plus) primarily recognises movement, but it can get an absolute reference point at least some of the time.
The Wii remote's original specification is a 3-axis linear accelerometer. It can measure rotation along 2 axes by virtue of being able to use the earth's gravity as a reference direction. But this same force of gravity makes it very difficult to extract actual motion in certain directions from motion induced by the force of gravity itself.
(believe me, I've tested the raw output from a Wiimote, and have a fair idea what it does)
Hence, forward stabs, and rotation about the axis of the remote aren't really possible.
Motion plus adds a 3 axis gyroscope to the equation, meaning you now have a direct 3 axis reading of the rate of rotation, as well as linear movements. Now you can be determine exactly how the remote moves with a high degree of certaintly.
What's missing? knowing where the remote is in absolute 3d space. But guess what? The Wii remote has always had a system for determining this... It's the IR camera on the front of the remote. The one that makes the onscreen pointer possible!
As long as it's pointed at the screen, it can give you a measure of distance between the remote and the screen, x and y position relative to the sensor bar, and the rotational angle of the remote. (in theory, you could build a more effective arrangement of IR leds than the sensor bar, and get more accurate meansurements than the existing one.)
Have a look at the Wii Sport's resort videos with regard to the sword-fighting demo. - Notice it gets you to point the remote at the screen at the start of the match?
This is to get an absolute reference point for the remote's position. After which, you can follow the exact movements of the remote by acceleration readings alone.
This approach is known as dead reckoning, and it's used, for instance in aircraft navigation when GPS isn't available.
You take a known starting point, then use measurements of relative motion to determine your position - It has a disadvantage that errors in measurement slowly make the actual position drift apart from the measured one, but with accurate sensors you can go quite a while without needing to confirm your absolute position.
Does Sony's system work better? It's possible.
But don't delude yourself into thinking it's MUCH better than Motionplus technically, because it isn't.
The difference is between absolute and relative tracking. Neither is definitively better than the other, and if you have a known starting position and accurate sensors, relative tracking has the advantage that you don't need an external reference point.
With absolute tracking, the system knows where it is only relative to an external point. More reliable in some ways, but if you lose sight of the reference point, you immediately lose your position.
Both have advantages and disadvantages...
The fact that it reappears in the same spots reaffirms that it only recognizes motion. The IR pointer simply positions the wiimote to an absolute position on screen. The PSMotion Control is absolutely free, so if your hand is resting on the side, the "sword" or w/e on screen will start out at the same exact spot. With the WiiMote Plus, it sets an absolute position (in the middle) of the "sword" so it just gets inputs of relative motion to determine movement.
The only advancement of Motion Plus is that it recognizes movement much better than the original WiiMote. It recognizes different motion upon immediate change (so you can swing left and the immediately swing right, and it'll recognize that), but it does NOT recognize the position of your controller in the 3d space. It simply puts an absolute "sword" on screen, and it moves to your movement.
The IR does tell the Wii the distance, but that's not to know the position of the controller in 3d space, it's to set the absolute position of the controller so that it can recognize depth movement. It doesn't see where the controller is like the PSMotion Control, it simply tell the Wii "the controller is 5 meters away, set the 'sword' to this distance so when controller moves in depth, move the difference on screen (ie. Z = -5)." Also, the IR is very rudimentary so that it doesn't know the position at all, it's just an invisible tape measure.
So to put it in an example:
Wii Motion Plus: if your hand is resting on the side of your legs, the "sword" on screen will be in the center (or where ever the developers decide to put it in the beginning). If your hand moves, the "sword" moves with it. But if you want seemless movement like in video games, you have to restrict your "sword" to a set of preset movements, so that it's not 1-1 tracking afterall, but the Motion Plus recognizes movement so well, that devs can put a LOT of presets and the Motion Plus will recognize every subtle differences and display those presets when called.
PSMotion Control: if your hand is resting on the side of your legs, the "sword" on screen will be placed exactly in your hand. You can move it or just stay still and the Motion Control and Eye will track its 3d position at all times and can recognize very minute movements and position so that it's complete 1-1 3D tracking, not just motion tracking.
I think the PSMotion Control might be better than the Motion Plus, but only games will tell. For now, all I can say is that they're different. So when you say that Sony is just copying Nintendo and that Sony isn't bringing anything new, you just might want to check up on that.
Sigh. It's different, yes. But not by enough to say that they can do radically different things.
OK. Compare this video: http://www.joystiq.com/2009/06/03/watch-the-playstation-motion-controller-in-action/
With this one: http://www.youtube.com/watch?v=acND4sO3pJs
(look closely, because this second video shows several different cases. One where the controller clearly resets to a standard position, one where it appears to determine a starting position from the IR sensor, then do relative tracking, and one where it pins the actual 3d coordinates of the controller in a single place. Using the most restrictive case to argue about the overall capabilities isn't very accurate.)
The IR does tell the Wii the distance, but that's not to know the position of the controller in 3d space, it's to set the absolute position of the controller so that it can recognize depth movement. It doesn't see where the controller is like the PSMotion Control, it simply tell the Wii "the controller is 5 meters away, set the 'sword' to this distance so when controller moves in depth, move the difference on screen (ie. Z = -5)." Also, the IR is very rudimentary so that it doesn't know the position at all, it's just an invisible tape measure.
Sorry. Had to pick on this one individually, because it's fundamentally wrong from a base technical perspective. The Wiimote's primary sensors (in the case of using motionplus alongside it) are 3 linear accelerometers, and a 3 axis gyroscope.
The linear accelerometers can determine linear movement in the X,Y, and Z directions. Even the Wii remote by itself can tell you this. - In theory, it means it should be able to tell you the movement of the remote in any direction (but not the orientation). If you move it up, down, left, right, forward or back, all cases should be detectable. (so you already have depth information.) The reason that doesn't work, is because you have the force of gravity acting on the sensors at all times. And because you have no way (with an unenhanced remote) of conclusively determining the orientation of the remote, you don't know which part of the force is due to gravity, and which is due to motion of the remote. THAT is the original technical limitation.
With a gyroscope as well, which the motionplus module provides, you can now get accurate information about the rotational angle of the remote as well. Thus, you can track the relative motion of the position of the remote accurately.
More to the point, the cursor movement of the Wii is done with the IR system. This means you can get a pretty accurate X and Y position, and a reasonable guess at the distance from the screen, and can probably deduce the rest from the motion sensors.
Once you have a starting coordinate, relative motion alone is sufficient until the margin of error becomes too large.
So what does Sony's video show?
It shows quite clearly that Sony's system does indeed recognise the 'position' of their controller at all times.
The Wiimote most certainly does not. - It recognises motion.
But you might want to check the logic here, because these two cases are pretty similar.
An absolute reference will tell you the exact position of an object with regard to the point of measurement (the camera, in Sony's case. Of course, their Eyetoy itself has been around for a long time, and this seems to represent a hybrid And of course it is limited by the accuracy of the sensor, and assumes nothing gets in the way). - Granted, because the camera in this case is in a fixed location, and provides a video feed, they can do the neat trick of mapping their controller position directly onto the video feed.
But in fact, from a technical perspective, this is pretty similar to the IR camera on the Wii (Which incedentally, has a resolution of 1024 by 768, and can capture motion at 100 frames per second. Due to bandwith limitations though, it generally provides the coordinates and intensity of up to 4 IR sources in the image. The Wii only uses two of them.), the reason Sony's system so much more impressive in apparent function, is because the Wii's IR camera has a field of view of maybe 90 degrees at most, and that's focused at the front of the controller, while the IR LEDs in the sensor bar are telling the Wii remote where it is in 3d space (From the IR arrangement the Wii uses, you can determine an accurate X and Y position, and a considerably less accurate Z position, as well as determine a 'roll' angle for the remote - but you can't distinguish 'pitch' and 'yaw' easily if at all, and you can't really detemine from the IR data alone wether the remote is upside down.), but only so long as the LEDs are within this narrow field of view.
The Playstation setup is essentially reversed. The positioning LED's are on the controller, while the camera determining positions is on the TV side. Obviously, you need a more complicated LED setup here to be able to tell one side of the controller from another, but the general principle is pretty similar to the IR camera the Wii uses.
You really want to see how similar the IR function is to the technology that sony has implemented? watch at 2:22 as he's shining a virtual torch around... That's the same principle as the onscreen pointer for the Wii.
And the first person shooter demo. Great. Except... That's almost identical to Red Steel.
Here's some more demos
Stacking blocks: That's a tricky one, but you don't need absolute position data to pull it off. Accurate relative motion would do it pretty much just as well.
Whiteboard / drawing example: Uh HELLO? I've witnessed the Wii pointer doing this. Accuracy is a good point. But the general idea? - Try the photo channel.
Selection / RTS comments - ahem. Do I even need to explain this one? The cursors being used are so obviously similar to the Wii's pointer that it should speak for itself. (I've always maintained the the Wii was the only console that had the input required to do RTS well, and the comments here just prove my point. - Pity no developer has ever bothered to try it. But I guess with Sony's new system it becomes a moot point.)
Sword demo: Hmm. Remind you of anything? Because it certainly reminds me of something. The character is likely generated using Inverse Kinematics. Other than that, it's very close to the Wii dev kit video's demo. (watch the motion of the Wii guy's arm's relative to the sword on the screen when he's hitting that dummy.) - And watch the character in sony's demo - It's posture does not match how the guy controlling it is standing, even if the hands are in the right place.
Throwing star examples: Pretty much the same in most regards as the Wii motionplus examples of similar motion
Bow and arrow: Hard to comment on this one, since it fundamentally relies on two controllers. Although it's likely that given how the system works, you'll temporarily lose tracking (for a split-second) doing this particular motion.
Fundamentally, you could duplicate it with motionplus, but it does pretty much rely on dual controllers. I would be quite interested to see how Sony's system interprets his posture when he drops down on one knee like he did at the end of this...
A lot of fun, sure. But there's nothing it's doing that is fundamentally unique except perhaps mapping it directly back onto the live video feed that the system is getting the information from in the first place.
If this works better than motionplus, it'd be because of presision, not fundamental capability. (and by precision I mean wether you can easily put something within a 1 cm space, or a 1 mm one...)
I can prove what a normal Wii remote can do, because I've experimented with it's raw output myself.
I'm quite curious to see just what the real-world consequences of the gyroscope in the motionplus module are on this raw output, because I already deduced ages ago that a simple way to overcome the limitations the controller had (before I ever heard of motionplus) would be to plug in the nunchuk (which has an accelerometer of it's own) and strap it to the remote using a bit of wood so that you cannot move them independently of eachother anymore.
You now have two accelerometers with fixed motion relative to eachother, and you can (in theory) calculate proper motion now. This, essentially, seems to be what motionplus does.
Different implementation, same result is what it comes down to in the end.
Place the Wiimote at a position where the sensor bar is visible, and just to be safe, making sure it's level. (due to limitations on determining Pitch and Yaw of the remote from IR data) You now have a known starting point and angle.
After that, the gyroscope and accelerometers can tell you enough to determine an absolute path from relative motion alone. At least, until your measurement error becomes too large, at which point you need a new 'fix', otherwise things become too inaccurate.
In any event, One to One control is doable by both, as far as I understand the underlying technology. - What Sony's got here could be (much) more accurate, but that doesn't mean it can fundamentally do anything that Motionplus can't. (and Sony's demonstration pretty much proves it.)
That's not to say it's a bad system, because it clearly isn't. And Nintendo suffers inherently because the Wiimote has issues by itself. (again, i've experimented with it's raw output. I am accutely aware of it's limitations. - And I quickly established what would overcome most of those problems (roundabout begin 2008), which pretty much seems to be what motionplus is. - Nintendo claims the reason it's being done now, rather than back then is a cost issue.)
So let me be absolutely clear. Sony's video does not fundamentally demonstrate capabilities that motionplus is incapable of replicating. It does however suggest it will probably do it with more consistent accuracy.
So well done Sony. Now go and do something useful with it...
