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Hard Choices: Stereoscopic 3D

Four eyes good, two eyes better?

Our resident hardware dreamweaver/bubble-burster Jeremy returns with an examination into whether 3D glasses and 120Hz monitors are what PC gaming needs. For more Hard Choices - including the only answers you need on processors, graphics cards, hard drives, monitors and motherboards - please click here.

I've got a hunch about stereoscopic 3D. I reckon it's on a 30-year cycle. According to the annals of history – otherwise known as Wikipedia - every 30 years or so sees a blip in the graph measuring interest in 3D before things revert to the long-term flatline.

So is the latest round of 3D flicks and games just a temporary craze? Or is 3D here to stay and just about to assimilate your PC?

The timeline starts in the 1890s, when British inventor William Friese-Greene apparently patented a system for capturing and displaying motion stereoscopic pictures, perhaps while researching into an automatic machine for polishing shoes.

Anyway, fast forward roughly 30 years to 1922 and you have the first known paying audience for a 3D flick. Add another 30 and you hit the 1950s and arguably the golden age of 3D movies.

Next up is the 1980s and another temporary blip, one which I personally can just about remember courtesy of some prepubescent memory tendrils – yes, I am that old. Which brings us neatly to the present day and the recent resurgence of 3D blockbusters.

See those stupid glasses? That's you, that is.

Intriguing, eh? Along the way, of course, stereoscopic 3D found favour as a genuinely useful tool for things like military aerial photography. And porn. Ah yes, porn. Ever the innovator. Even the Nazis made a few propaganda flicks in 3D, and they didn't mess about.

All of which begs the questions whether 3D movies are here to stay this time and if so – and much more critically – is stereoscopic 3D therefore the next big thing on the PC?

I'll spoil the rest of this post right here and say the answer is negative. 3D movies, in my expert and peer-reviewed opinion, are bloody awful. And stereoscopic 3D is not going to become the norm on the PC any time soon.

However, that doesn't mean it's not interesting to have a think about the problems with 3D technology. Moreover, just because 3D isn't going to entirely assimilate the PC, it can still make for some occasional fun in the right format. And if you're going to fork out, you'd better know how the options compare and where to spend your money.

So, let's get the numpty bit covered. What is 3D? We humans have two eyes. Each eye views the world from a slightly different position and and captures a slightly different image. Your monkey brain receives these offset images and composites them into a single mental picture with depth and perspective.

Result? Glorious 3D. So, the basic requirement for any 3D technology is a different image from a suitably offset perspective for each eye. The question is how you achieve that.

For bona fide 3D movies, that's a pain, because it means you need two cameras offset roughly like human eyes. You can kludge it, but the result is usually that cardboard cut-out effect where objects look like flat boards arranged at different depths. Actually, that can apply to movies made the right way, too, but I digress.

NVIDIA's idea of 3D gaming, apparently

As it happens, computer games are perfect for stereoscopic 3D. If you have a software engine rendering a 3D model of the world in real time, it's a very simple step, philosophically if not in terms of performance, to render it twice from two different angles and thus generate depth and perspective for not just the whole image but for the objects in it, too.

Even better, with a software 3D engine, it's pretty trivial to tweak the z-buffer values for objects and thus dynamically adjust the depth of view or, er, 3Dness of the image, to suit your preferences.

The difficulty is getting the two images to hit the backs of your eyes separately, in the right order and fast enough to create the illusions. Right now, there are two different widely options for the PC. Both involve wearing a pair of silly glasses.

Glasses-free technology, that works thanks either to similar principles to those animated rulers you had at school or more advanced head-tracking malarkey is emerging, but it's early days. From what I've seen, it's still a bit crap.

So let's talk about the stuff you can buy and that works fairly well. Option one we'll call passive polarised. The idea here is to have polarised filters in front on your eyes. If we're talking linear polarised light, you offset the filters by 90 degrees. Then you pump the image being generated by the display for each eye through the corresponding polarised filter and bob's uncle is poking you in the eye. Or something.

These days, circular polarisation is used which allows for a bit more freedom in terms of head tilt than linear polarisation. Anywho, the main advantage of polarisation is that you only need cheap, passive glasses with filter lenses. And so we have throw-away glasses for 3D cinema.

Yes, you can buy 3D laptops, but do you really want to?

The problem is that it puts all the burden on the display. For PCs, that means LCD panels with polarised filters built into them. Even worse, with all the polarised 3D monitors I'm aware of (shout out if you know differently) you effectively lose half the resolution in 3D mode. That's because the polarisation is done in alternate scan lines of pixels, one for each eye.

You also lose some brightness and vividness, which is always the case any time you stick a filter in front of a light source. The alternative is to make the glasses do more of the hard work, which is exactly what happens with active shutter technology. The mechanics here involve glasses fitted with liquid crystal lenses that can be switched to either allow light through or block it.

At the same time, the entire display alternates between the images for each eye. The tricky bit is refreshing the screen fast enough for fluid motion since double the frame rate is required to feed individual images to each eye and then getting the glasses and screen correctly synced.

However, it doesn’t actually require much from the display. You can use a standard LCD panel. You just need electronics to support high refresh rates.

Currently, there are a number of polarised 3D monitors on sale, such as the LG DM2350D (you can read my review here). I'm not a huge fan – they're dim and you can see the loss of resolution along with a slightly odd comb effect due to the alternate line tech.

In that context, we don't have to worry about software support for polarised screens. Which leaves us with active shutter technology. The 800 pound gorilla is obviously NVIDIA and its 3D Vision technology.

I've experience of both the first generation 3D Vision and the revised version with so-called LightBoost. It's certainly the best stereoscopic 3D solution for the PC I've tried. It's fairly easy to set up and the game support is as good as it gets.

The results in terms of visuals are also probably the best 3D images I've seen. What's more, any 3D Vision-compatible monitor will support 120Hz refresh in 2D mode, which if you haven't tried it is bloody lovely for everything from just pushing windows around the desktop to gaming.

Right now, NVIDIA's 3D Vision kit is your best option

The only problem there is that there aren't currently any monitors with high quality IPS or VA panels that support 120Hz (before someone pipes up regards a certain species of 27-inch Korean screen with an IPS panel and 120Hz overclockability, that's a whole different ballgame and one you can expect to hear about from Alec soon).

In any case, I struggle to buy into the stereoscopic-3D-on-a-PC-monitor proposition. I'm not convinced that it truly adds much to the experience on a desktop screen. But I am convinced the glasses involved are silly and that eye discomfort is common with extended use. Part of the problem is that with a screen so close, the fact that you're faking visual depth via a screen surface fixed focal point gets your brain and eye muscles in a right tizz.

That said, where I think 3D gaming really works is with an HD projector. You can now get a 3D compatible high refresh HD projector for about £500 and it really is a lot of fun. Using a projector also makes the need to wear glasses somehow less intolerable. Gaming on a projector is only ever going to be a niche activity you do occasionally, so throwing some glasses into the mix isn't enough to spoil the novelty.

As it happens, the second-gen LightBoost 3D Vision stuff is particularly good and really is pretty vibrant, but you will need a LightBoost compliant screen. Of course, all of that only applies if you have an NVIDIA graphics card or are willing to buy one.

So what of AMD's HD3D tech? I have to be honest here and say I haven't used this at home, only courtesy of some AMD arranged demos. So, I don't have a great deal of insight regards stability and game compatibility.

What I can say is that in traditional AMD style, the whole thing is a bit fiddly. You'll need a 120Hz display with DisplayPort connectivity. To that you add a Radeon HD 5000 series or higher GPU. For most games, you also need some middleware drivers that depend on third parties as much as AMD.

Overall, I think you'd have to be pretty committed to AMD to choose HD3D over 3D Vision. Stereoscopic 3D is also one area where NVIDIA's sometimes suspiciously close relationship with developers can only help. I also think stereoscopic 3D as a broader tech for the PC will remain niche as long as you have to wear glasses and tolerate compromised image quality.

But if you've got a bit of cash to burn I wouldn't cross you off my Christmas card list if you forked out for some 3D Vision kit. Worst case scenario, you can stick it on ebay come 2040.

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Jeremy Laird