Topic: could this be a wii game?

[willie1234]

hey - this is a pretty sweet article about drawing free form in 3d space and then producing plastic models from the drawing.  in this case furniture.
http://slashdot.org/article.pl?sid=06/10/29/1540241&threshold=3

It made me think, aside from actually producing real objects as this article does, could we get a Wii game where you draw 3d models (using the wiimote) that you can then interact with in a game of some kind?  This would be tremendously cool to me.  Even if it were a non-game, doodling type of application.  Ie. a 3d model of Microsoft Paint would be fantastic.

thoughts?

[Edfishy]

Sounds like a good idea for a downloadable "Paint Channel" to me.

[zakkiel]

The Wii does not detect displacement directly, so unfortunately, no.  

[willie1234]

not sure what you mean by displacement.  do you mean exact location in 3d space? if that is the case, then a mouse also does not relay exact 2d location (like drawing pads do for example), only movement in a direction, which the wii can also do in 3d.  

So while not perfect, I think it would be workable for as a mini game, or channel as EdFishy suggested.

[zakkiel]

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not sure what you mean by displacement. do you mean exact location in 3d space? if that is the case, then a mouse also does not relay exact 2d location (like drawing pads do for example), only movement in a direction, which the wii can also do in 3d.

No, a mouse detects displacement from an origin. In reality, there is nothing that will detect absolute position, only position relative to something else (like a starting location). It's one of the symmetries of space time.

The Wii does not detect displacement. It can sense acceleration, which could in principle be used to tell you displacement, but unfortunately the Wii accelerometers do not have the precision to do this for even much less demanding applications than decent 3d drawing.  

[Smoke39]

The Wii remote doesn't just have accelerometers.  That's what the sensor bar's for: to get more information on the actual position of the remote.  The nunchaku attachment only has accelerometers.

[willie1234]

smoke, that's what I understood too.

[zakkiel]

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The Wii remote doesn't just have accelerometers.

You are  mistaken.  

[Smoke39]

That black bit on the front of the remote houses an IR sensor.  It uses the angles of the lights emitted from the ends of the sensore bar to calculate its position relative to the bar.

[Kairon]

But the IR camera can only detect the lights (and thus extrapolate it's ROUGH 3D position (extremely rough, because the accelerometers aren't able to detect the full extent of G-foirces humans can put it through)) if it's pointing at the screen....hmmm....

This seems cool, but it actually seems not intuitive at all...

~Carmine M. Red
Kairon@aol.com

[KDR_11k]

The camera is used for pointing, things like batting in Wii Sports where you hold the remote in a way that it cannot see the IR bar are controlled by the accellerometers. And I'd be surprised if those things couldn't be used to determine displacement since noone cares about accelleration alone, only the resulting displacement.

[Kairon]

I think I read somewhere that the Wiimotes can only detect acceleration up to two G's, which we humans can exceed... like when we swap a fly for example?

Thus, if we ever accelerate the Wiimote beyond 2G's it no longer has accurate information on how fast its moving and can no longer be sure of where it is.

NOW, if we want to know distance from a reference point, then we need the IR functionality. This is why we need this for pointing: distance let's us know it's 3-dimensional relationship to the sensor bar and by proxy the TV. This way we can detect distance from the IR bar to replace our limited knowledge of acceleration and get a better idea of where the Wiimote is in 3D space: are we drawing a circle that is perpendicular to the plane of the tv or just drawing a line?

Either way this is getting way too complex and with too many caveats to make drawing 3D models in empty space in the real world and having them come to life in the virtual world a simple proposition for players OR for developers.

~Carmine M. Red
Kairon@aol.com

[Ceric]

2G's sounds to few.

[zakkiel]

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And I'd be surprised if those things couldn't be used to determine displacement since noone cares about accelleration alone, only the resulting displacement.

Acceleration tells you force, which you care about a great deal in, oh, every Wii Sports game. The reason you can't use the accelerometers for displacement is, as I said, they aren't accurate enough. A small error in acceleration creates small errors in velocity, which add up to big errors in displacement. For example, consider moving the controller from rest a foot to the left, and stopping. If the accelerometer makes a small positive error at the start and a small negative error at the end, it will think you haven't fully stopped moving and will register the Wiimote as continuing to drift to the left in perpetuity. You would feel like the game brush was on ice, constantly slipping around. You could of course set the program to force any velocity below a certain threshhold to zero, which would prevent drift but would also prevent it from reading any slower motions - of exactly the sort you would use in a drawing game. Which is why every game that uses the accelerometers requires quick movements, I'm guessing.

[UltimatePartyBear]

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If the accelerometer makes a small positive error at the start and a small negative error at the end, it will think you haven't fully stopped moving and will register the Wiimote as continuing to drift to the left in perpetuity.

But it updates many times a second.  It would not continuously make the same error even while it was sitting still.  Even if it did, gravity is also a constant force on the Wiimote, and it doesn't have that kind of effect.

[KDR_11k]

Yes, errors could mess that up but accellerometers are already being used in that way and the error is not enough to make a difference. Remember that the mouse the Wii tech is licensed from doesn't use an IR marker bar and instead uses rotation by tracking multiple accellerometers.

[zakkiel]

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But it updates many times a second.

Yes. However, most accelerations for hand movements are very brief, so exactly how often becomes a relevant issue - you need to update at least several hundred times per second just to avoid sampling errors from bandwidth restrictions. To compensate for sensitivity restrictions, you would need a lot more bandwidth.

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Remember that the mouse the Wii tech is licensed from doesn't use an IR marker bar and instead uses rotation by tracking multiple accellerometers.

One of the engineers in the Iwata interviews specifically said they couldn't get around the IR bar specifically because they couldn't get it accurate enough otherwise. There are, of course, accelerometers small enough, accurate enough, and with sufficiently high bandwidth to get around this restriction. Thus far, the ones I've seen that meet all three criteria range in thousands of dollars. I would be interested to see the link, since 1) I hadn't heard that the Wiimote was based on a 3d mouse, and 2) the only 3-d mice I've heard of that tracked displacement used external references. There are, of course, gyroscopic mice that can detect orientation with great accuracy. Different technology.