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VR Interfaces: Nvidea GeForce 3D Vision


Overview of Nvidea GeForce 3D Vision
At CES 2009, Nvidea unveiled a new 3D, glasses based system that bucked the trend for the year. Rather than going with anaglyph, the main technology showcased by its competitors, Nvidea unveiled a system of active glasses. Specifically, shutter glasses. The frames alternate polarisation to block light out every second frame, so that each eye gets half the screen update rate of any normal monitor, but will work with a normal output stream just fine.

The graphics cards of the computer system send a slight perspective shift akin to the difference between the perspective of each of the two eyes, each frame, building up a compound 3D effect that is superior to anaglyph. The result is a full colour spectrum without undue load on the graphics cards ? each image is sent only once, not twice. Thus, there is no necessity to simplify dynamically rendered screens to work with this type of system.

As a result, viewers can look round the room, and not see anything different, but when they look at any TV or monitor system, it only updates at what is effectively half its normal rate. To combat this, screens with faster refresh rates are required, and likewise a faster sync rate for the glasses. The 3D vision glasses are actually synced to 120hz, and require monitors that operate at 120hz to work properly. They will still work ? sort of ? with screens that refresh at 60hz, the standard monitor type, but each eye gains two frames instead of one, which potentially destroys the 3D effect.

The reason for choosing 120hz as the sync rate is fairly obvious. The glasses halve the refresh rate of any display screen viewed, and 60hz is the minimum safe update speed that does not cause headaches and nausea with continued viewing for most people.

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