I talked about hacking Wiimotes, not hacking WM+. That's what we were talking about: the accelerometers in the Wiimote, that could be used to integrate velocity and then position. The WM+ is only necessary to subtract gravity from the reported acceleration vector. Any precise way to know in which direction is "down" would work equally well.

Uhm, and please tell me which sources you're missing to justify something I said?

@MrHappySquirrel

Of course, we can't comment on the troubles that the real final implementation of any of these technologies will show. We may very well find that the final product doesn't work as well as advertised in crucial use cases. But we can surely talk about vantages and problems that derive from design choices that are publicly disclosed.

i think "natal" is far more advanced tech than what sony showed off, sony's version of motion controls is a slighty more advanced wiimote and "natal" is the future of motion controls.

You're wrong about the Wii MotionPlus ... From Wikipedia (with citations):

"The device incorporates a dual-axis^[13] "tuning fork" angular rate sensor,^[14] which can determine rotational motion. The information captured by the angular rate sensor can then be used to distinguish true linear motion from the accelerometer readings.^[15] This allows for the capture of more complex movements than possible with the Wii Remote alone"

In other words, the device isn't to subtract gravity (which is already possible on the Wiimote) the device is actually a fairly large improvement on the motion sensing capabilities of the Wii

meh, EA and Motion crap can sit in their corner.
Natal fails , PSmotion fails , Wiimote Fails
sorry.

We're (well, I am) nerds. I personally care more about the technology than the games. I mean, I do love playing games, but technology is what borned my love.

you can do that with a wiimote without motion plus already, would just be even more accurate with WM+, the only diff is you can only do 1 at a time with a Wiimote, you know, kinda like a mouse.

edit: now that I think about it, you can do that with 2 Wiimotes, and you can also do that with Natal because it can track 3D depth, so you use 3 fingers from each hand as an input device(though can be a little flawed depending on angle,) you can literally move the blocks front, back, twist, and all sorts of things. hate to break it to you but it can be done with all the controllers, or a PC setup.

I don't know your background, but you probably didn't entirely understand what you just quoted. That wikipedia voice supports exactly my point.

Warning: longish physics divulgation follows.

I'll try to explain, and you can google or research real books for the details: there's a general principle in physics (Einstein's equivalence principle) that says that gravitational forces are locally indistinguishable from apparent forces in a non-inertial frame of reference.

A non-inertial frame of reference is basically your Wiimote when you accelerate it, say by shaking it. The apparent forces are the "inertia" forces measured by the accelerometers, like when in your car you brake, the car decelerates and you feel pushed forward. That forces pushing you forward is the apparent force due to the deceleration, and it is proportional to your mass, exactly like the gravitational force. The equivalence principle says that if the car had all windows painted black so that you can't see the outside, you could not say if you felt pushed forward because th car is braking, or pulled forward by a gravitational pull, as if the car was diving nose down.

The inclination relative to vertical of a Wiimote without WM+ can be measured by its accelerometers exactly because of this principle: if I take the Wiimote and put it at rest on a table, the accelerometers inside won't measure 0: one of them will measure a vertical acceleration of 1g, because it can't distinguish between gravity and the force that it would feel in absence of gravity, but being vertically accelerated (see here about accelerometers).

Or looking at it in the other way: if the Wiimote is at rest, I can read its accelerometers to see which way the gravity pulls, ie its orientation from the vertical.

In the same way if I shake the Wiimote horizontally the accelerometers wil measure an acceleration made by the sum of the "real" motion one and the gravity-equivalent one. Follow the link marked [15] in the wikipedia voice, and you'll be directed to a short movie by the IntelliSense guys showing exactly this phenomenon with accelerometers readings.

On the contrary gyroscopes use a very different mechanism to measure orientation changes, thus they can keep a reference direction, and that's useful because this way not only you can measure rotations with a greater precision, but you can know which direction is "down" in real time.

Your wikipedia says: "The information captured by the angular rate sensor can then be used to distinguish true linear motion from the accelerometer readings". Accelerometer readings = a mix (vectorial sum) of the gravity force and the inertial forces due to the motion. Thanks to the gyros we can extract from this mix only the "true linear motion" component, by subtracting a 1g vertical component and the smaller side components due to rotation.

I hope to have clarified more than mystified.

Update: I stand corrected on one point. That is that WM+ has another good use in position tracking besides pointing down, that is to filter out most of the little jitter that comes from your hands slightly shaking. That's another good feature it brings to the table.

That would work with 2 Wiimotes as long as they keep "seeing" the led bar, so that they can use the IR pointing. But not if the manipualtion requires you to rotate them alot.

you only need to use the IR when you move the blocks front and back(you can also use buttons to reset the distance, it'd be like dragging, basically just like a mouse) all the rest can be done with tilt and twist, with natal, you'd use some voice commands which is logical, my point is that you say it can't be done on any other inputs, but they can all be done, that's all I'm trying to say.

^Maybe I wasn't clear, note that i said "any console interface up to day" as in currently available console input methods. You can surely do that with specialized 3d input methods used in CADs on PCs, and of course in the future you'll be able to do that with Natal motion detection.

Also, you could do all of that with enough button presses (including all shifts, all rotations etc), but I was talking of direct, analogic manipulation.