So there I was, breaking in my GeForce 3D Vision glasses with a few stimulating rounds of Call of Duty 4, when my wife asks me why I was "wearing those silly goggles".

After explaining their function, the response I got kind of stumped me - aren't games already in 3D? Yes, I guess they are, but these 3D worlds are presented to us on the plain old 2D surface which is our PC monitor, so there's no depth of field, and thus the brain isn't tricked into thinking it's a real three-dimensional environment.

Enter the Geforce 3D Vision glasses and the Samsung 120Hz LCD monitor, here today to quite literally add another dimension to the video gaming experience.

3D movies and games are not a new concept, in fact I remember seeing my first 3D film almost twenty years ago with the red-and-blue tinted glasses, but this particular system combines the latest technology in the field with the marketing power of Nvidia, one of the world's biggest graphics card manufacturers. Even 3D gaming hardware has been on the scene for a while - IZ3D is an alternative product that's been out for a few years now.

How does it work?

The concept is quite easy to understand, in fact the system Nvidia have used is actually really simple. First and foremost - for the brain to be tricked into perceiving a three-dimensional picture, your eyes must each receive an image of the world from slightly different perspectives (as they do when they're inserted into your head). This gives us depth perception; the ability to distinguish between close objects and those that are far away. Given this, the GeForce 3D Vision system starts by rendering two different environments - the first from the perspective of the left eye, and the second from the perspective of the right eye. What happens next is the tricky-dicky part.

The two different environments mentioned above are displayed on-screen in alternating frames. In other words, the first frame would be from the left eye perspective, the second frame from the right eye, third from the left and so on ad infinitum. If you were to look at these images being displayed on-screen without the glasses on then you'd mostly see a blurry mess as the two different perspectives overlap each other. What happens now is that the left-eye perspective needs to be displayed only to your left eye, and likewise for the right. This is where the "silly goggles" come in to the picture.

The glasses work on a 'shutter' system, that is - at any one time, you can only see through one side of the glasses. When the left eye perspective is displayed on-screen, only the left hand side of the glasses are see-through. Then when the right eye perspective is displayed in the next frame, only the right eye can see the screen. This 'flipping' between eyes is done many dozens of times per second so your brain doesn't actually notice it happening, but rather it combines the two perspectives as one cohesive and three-dimensional image.

The monitor that you need to view this on isn't really anything special. The only requirement is that it can display a 120Hz image - i.e. refresh the image on-screen 120 times per second. Most modern LCDs only do 60 - 75Hz, so it's likely that your current monitor will not fit the bill. The monitor has to be capable of 120Hz because it needs to present 60 images per second to each eye - anything less would be flickery and hard to watch.

Installation

Getting the 3D system up and running was pretty painless. The drivers on the CD weren't compatible with the graphics card I was using (a Nvidia GTS 250) so I had to download the latest drivers from Nvidia.com, but it's always a good idea to use the latest drivers for this stuff anyway. After installing the drivers and plugging in the control unit a setup wizard took me through the steps to configure the glasses, which basically consisted of turning them on and ensuring they worked.

The control unit serves a number of purposes. It is an IR transmitter which talks to the wireless glasses to syncronise the shutter timing, it has a button on the front to turn the 3D effects on and off, and it also has a scroll-wheel on the back which you can use to adjust the amount of the depth-of-field effect on-screen (i.e. for a shallower or deeper 3D effect).

Gameplay

It was pleasing to see that there's no special setting up or patches to install to get 3D games to work with these goggles. The only adjustments necessary are provided to you through an on-screen overlay. This is displayed when you start up a game, and it instructs you on what graphic options to fiddle with to get the best 3D effect. Nvidia must have spent a lot of time testing and documenting a wide variety of games and how they worked with the glasses. Remind me to apply for a job there one day!

To get a true sense of what the system was capable of, I tested them against some titles from my standard suite of test games, namely Call of Duty 4, Fallout 3, Crysis Warhead, Race Driver GRID, and Trackmania Nations Forever.

At this point it is probably prudent to point out that I can't actually show you any 3D screenshots as you'd actually need the 3D glasses to view them, in which case you could just play the games and see for yourself. So anyway...

The good

Buy these glasses if you are a racing fan. There's no two ways about this. Race Driver GRID was so intoxicatingly mind-blowing in its realism that I spent most of my time with the glasses playing it. I definitely recommend the dashboard view for this, even if it's not your preferred camera view. I know it sounds cliché, but it really is like you are there, in the game. Immersion is something which I definitely think is underrated in the video game market. Good games, like good books, movies or theatre, should temporarily suspend reality for the viewer and take them on a journey, and these glasses definitely do that.

The other racing title I tried - Trackmania Nations Forever - unfortunately isn't a supported title and suffered from major glitches, however - the parts of the game that did decide to work in 3D looked even better than GRID. The detail of the cars was truly mesmerising, and it added another layer of sheen to an already graphically beautiful game. Hopefully the next instalment in this series fares better in 3D.

One other very good thing about this system is the screen itself when it's not in 3D mode. If you haven't seen a 120Hz screen in action you owe it to yourself to check it out. I honestly spent a full minute swirling the mouse cursor around in circles in windows the first time I enabled 120Hz mode because I just couldn't believe how smooth it was. Playing games at 120 frames per second with 3D effects disabled also has to be seen to be believed, and should be deeply considered by all those people who miss playing on their big old 100Hz CRT monitors - especially you hardcore Counter Strike nerds.

The bad

Do not buy these glasses if you are an online first-person-shooter fan. Do buy the monitor though (as above). For just single player FPS games, the 3D effect is still pretty cool, although not as effective as for racing games. For online FPS games however, it's more of a distraction and your performance will suffer. In Call of Duty 4 in particular, motion was severely jumpy when 3D was enabled and it makes it incredibly difficult to aim accurately.

More generally, even the games that did look good in 3D had numerous problems, most common of which were artefacts, or crazy blur effects that flickered randomly on the screen. Not conducive to a good experience.

Other abnormalities were common such as mismatching images, especially outdoor scenes with clouds. When a cloud is rendered for one eye but the not the other, it gives you a headache rather quickly when you try to focus on it. In fact for most games you'll start to get a bit of eye-fatigue in less than an hour of playing. I'm not sure if there's any way around this unfortunately.

My last complaint is that enabling 3D mode drops your video card's performance significantly because it has to render two different environments - meaning you'll lose up to half of your precious frames per second. This won't be a problem for those with the latest and greatest Geforce GTX cards (the system doesn't work with ATI cards by the way) but even my relatively grunty 1GB GTS 250 started to struggle a bit on some games, particularly Fallout 3 and Crysis.

Conclusion.

At $499 for the glasses and an extra $700 for the monitor, I'd hazard a guess that most of you wouldn't purchase these on a whim. If you really are an avid gamer, and you have the spare cash, then I say go for it. The 120Hz monitor will enhance your computing experience on many levels, and the 3D effects in-game can be seen as just an added bonus. For the rest of us, those twelve hundred pingers could finance many other worthy purchases.

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Our thanks to PlayTech for providing the review samples.