6DOF magnetic trackers have been the standard for Virtual Reality. They are used to track the position and orientation of the head and one hand (normally). Usually the hand tracker will be attached to a “wand” with a joystick and buttons. Polhemus is one of the most famous companies, and they make the Fastrack and some newer trackers with offensive or racist names.
Unfortunately, they cost thousands of dollars, even for old ones.
But a new company called Sixense have created a new consumer priced magnetic tracker, and are hoping to cash in on the motion control craze caused by the Wii, Natal, and PlayStation Move. But they are targeting the PC.
The Sixense consists of a small base station and up to 4 (but normally 2) wireless tracked wands. The limit of 4 is based purely on the wireless RF stuff, the tracking tech could track unlimited controllers. The position of the wands are tracked with 1 mm accuracy within a 6 foot radius of the base station. The rotation is tracked to within 1 degree. Because it is magnetic, there are no line of sight issues. And unlike optical tracking, which has a range of say 75 degrees in front of the camera for the PlayStation Eye, the magnetic tracking has a range of 360 degrees, tracking just as well behind the base station.
The wands are identical, but are designed to be used one in each hand like a Wiimote and Nunchuk. Unlike polhemus trackers they are kind of bulky (but wireless), but it still looks like you could mount one on your head for head tracking without too much trouble, which is what I would do with it. Of course, head tracking
The only downside to full 1 to 1 6DOF tracking like this, is that there is nothing to stop your hand from moving through any virtual objects. They demonstrated a table tennis game where your paddle can go through the floor. There’s no easy way of stopping that. They demonstrated Left 4 Dead 2, and your crowbar can easily go through the skulls of multiple zombies without ever being slowed down, again there’s no easy way of stopping that. I think they even demonstrated a golf game where the club seemed to penetrate the ball on slow swings, which probably demonstrates the difficulty of implementing Newtonian physics when there’s no such thing as “force”. The laws of physics don’t really mention position.
Which is why the Novint Falcon is so cool, as I mentioned in my previous post. It allows the virtual world to exert forces on the user, and thus allows the user to exert forces on the world, rather than just applying positions or velocities. Unfortunately it’s hard to safely scale up something like the Novint Falcon to a 12 foot work area instead of a 4 inch work area, hard to make it 6DOF instead of 3, and hard to make it track more than one part of your body.
But I really want a Sixense tracker.
Currently, Sixense’s product is called Sixense TrueMotion, and you can only get it as a devkit. They were originally planning on releasing in 2009, but they didn’t manage that, probably because of a deal with Razer. You know, Razer, the company that develops precision gaming mice for the PC. You see, Sixense have done a deal with Razer, and Razer will be releasing the Sixense device as a Razer product after Razer redesign the look and performance of the device. Razer have their own wireless tech with very low lag, that they use in their wireless mice, so hopefully that will cut down the lag from the current 40 ms (which still isn’t bad). You can see Sixense in the Razer website’s product list, but ignore the illustrations that make it look terrible (the illustrations even have wires, when the product is wireless) and the comparison table that isn’t very accurate.
Sixense have also done a deal with Valve, that should ensure all future Valve games have support for the Sixense trackers. Half Life 2, and Left 4 Dead 2, have been demonstrated with the Sixense trackers.
To download the Sixense SDK, you actually need to install steam. Then you can click on the Tools tab, or choose Tools from the View menu if you don’t have a Tools tab. Sixense SDK will be in the list. There is supposed to be an FPS toolkit too, but I couldn’t find it.
