Under the hood with Nintendo's 3D baby ~ CK

Tomorrow sees the UK launch of the Nintendo 3DS, the world's first video game console capable of glasses-free 3D. Will this new display technology add some depth to gaming, or is it just another gimmick? New Scientist has been testing the device to find out.

The 3DS has two screens, just like its predecessor the Nintendo DS. The bottom touch screen hasn't changed much, but the top screen is now wider, and more importantly 3D. There's no denying that the 3D effect makes a stunning first impression. Boot up the device and you're presented with a menu of options accompanied by 3D animations on the top screen that seems to float behind the display. The 3D effect mostly goes into the screen, but objects can also appear to pop out above the console.

Games look equally impressive. Titles like Street Fighter and Resident Evil are essentially shrunk-down versions of the Xbox 360 and PS3 games - quite literally, because the 3D effect makes characters look like miniature figures - while 3DS exclusives like Kid Icarus really show off what the console can do.

(Image: Noah Berger/Bloomberg/Getty)

The 3DS also comes with some built-in augmented reality (AR) games that overlay virtual characters on the real world, courtesy of the pair of cameras built in to the outside case. These can also be used to take 3D photographs, while a single camera on the inside lets you take 2D pictures of yourself.

Hold still, this will hurt

So Nintendo seems to have delivered on their promise of 3D games in the palm of your hand, but how does it work? All 3D displays work by sending one image to the left eye and another to the right, but the 3DS achieves this without the need for specialised glasses. That's because the splitting is done within the screen itself by a device called a parallax barrier, which sits in front of the LCD screen. The left and right eye images are interlaced across the screen, but the parallax barrier ensures that each eye only sees one image, creating the stereo vision effect. Watch the video above to see it in action, along with the AR games and 3D camera - unfortunately we can only film it in 2D, but you get some idea of how it works.

Of course, this parallax technique only works if your eyes are in the right place.
The 3D effect is best when looking straight at the 3DS from a distance of around 30 centimetres, though this can be adjusted with a "volume" slider to the right of the screen, which varies the 3D depth or can even turn it off. That's fine when the console is still, but some games use the internal accelerometer and gyroscope sensors to track your movements, making it easy to lose the correct focal point.

I had problems even when the console was stationary. Every time I used the 3DS, even for a short period, I'd experience sharp headaches that would take some time to fade. But anotherNew Scientist reporter took the 3DS home for a week, and his children had no such problems - "Wow" was their only reaction to glasses-free 3D.

You know, for the kids?

Nintendo warns that children under six should not use the 3D effect, and provides a parental lock system to disable it. "We've looked at all the research and evidence out there, and that has suggested that children under the age of six shouldn't view 3D images at all," explains Nintendo marketing manger James Honeywell.

Ultimately we are trying to act as a responsible company. We just want to make sure that we are giving parents all the information they need to make that decision for themselves

The built-in health and safety manual also warns gamers to take a 10- to 15-minute break every half an hour when using the 3D effect, and to avoid it all together while travelling as a passenger in cars or on public transport. But will people actually heed this advice, since young children on long journeys are prime consumers for handheld consoles?

I raised these warnings with Bernard Chang, honorary secretary of the Royal College of Ophthalmologists, who explained:

Very little is known about how vision develops in children - we don't have full knowledge of how it actually works

So Nintendo is erring on the side of caution. "I suspect that it's mainly precautionary, because this sort of technology hasn't been around for us to see what happens with it, " says Chang. While children can safely watch 3D movies, most only last a couple of hours - 3D games have the potential to be played for much longer. Chang adds:

If you're using that sort of screen day-in day-out, does it have any potential side-effects on your vision? Nobody really knows

3D is good for you

Using the 3DS could even be beneficial, helping to diagnose problems with 3D vision. "If a child can't actually see the image as three dimensional that might pick up problems earlier" he said. As for my headaches, Chang suggested they would go away over time:

Headache from straining your eyes is quite a common thing. There's a learning curve to seeing 3D on the screen, I'm sure

Vision concerns aside, the 3DS is a genuinely impressive piece of kit and the start of a new era for 3D. It's not the first commercially available device with glasses-free 3D - Fujifilm has a range of cameras that can both capture and display 3D - but if it replicates the success of its predecessor, the best-selling handheld console of all time, it's likely to be many people's introduction to the technology.