ViewSonic’s V3D231 – Passive 3D vs. 3D Vision
Passive S3D vs. active shutter 3D Vision
The ASUS display is brighter out of the box compared to the ViewSonic display because it needs to compensate for the active shutter glasses dimming the screen’s image with 3D Vision. When actually comparing 3D across the two platforms, the passive polarized glasses with a less bright screen still delivers a brighter image than even the greatly improved 3D Vision 2. However, there are some things that the prospective buyer needs to know about Passive 3D before declaring it the “winner” versus the active-shutter 3D Vision.
We are comparing the passive 3D that ViewSonic uses for the 60Hz V3D231 display to Nvidia’s more expensive active shutter glasses with the 120Hz ASUS VG236H. The ViewSonic V3D231 is a 60Hz passive ‘FPR’ display, also called ‘line interleaved’ display. With these type of displays, half the vertical resolution per eye in S3D mode is expected.
Polarized Passive 3D
Polarized glasses have the advantage of being relatively inexpensive – more expensive than the cheap throw-away anaglyph glasses but much cheaper than the active shutter glasses chosen by Nvidia. AMD calls their implementation of stereoscopic 3D, “HD3D” and polarized 3D glasses and passive displays seem to be more popular with them and their partners than using the active shutter glasses and 120Hz displays which they also support.
Polarized passive 3D cuts the resolution in half horizontally because a passive S3D system takes one HD image and splits it in two. The result is that from an original 1080p image, each eye now sees a 540p image which is half of the combined resolution that an active system offers. This loss of resolution results in less detailed images than the active shutter system. In addition, the missing lines can be annoying if the user fixates on them or sits too close to the display. Plus, text may be difficult to read in some games and passive 3D adds unwanted aliasing due to the loss of half of the vertical resolution compared with the 3D Vision’s full 1920×1080 resolution per eye.
The surface coating is the standard anti-glare matte finish that ViewSonic uses on all of their LCD/LED models. The polarizer film is special. In a traditional display, there is just one orientation for the front polarizer film and one orientation for the rear polarizer film. In a polarized 3D display, the alternating rows will have opposite polarization. This is the way that content to each eye is controlled spatially for the V3D231 rather than time multiplexed as is done in the active 3D that ASUS uses for 3D Vision. The lenses always stay open in the polarized glasses while they are alternately switched on and off with the active method.
Creating S3D with active shutter glasses and 3D Vision
Using shutter glasses to create 3D Vision, each eyepiece consists of a single LCD screen that uses a polarizing filter. The screen can be made either transparent or completely dark by varying the voltage sent to it. As the frame of an image is shown on the main display, one eye’s LCD will be transparent while the other will be black. When the next frame appears, the orientation of the lenses is switched and the screen that was black will now be transparent with the voltage toggling, and it is synchronized with the main display’s refresh rate using the IR emitter (or USB port for the wired glasses). This is called, “alternate-frame sequencing”.
Simply put, 3D Vision works by sequentially displaying offset “left” and “right” versions of each frame in a game, and blocking the vision from one eye or the other by darkening the shutter glasses in synchronization with the display. Putting on the glasses and switching on 3D Vision immediately darkens the scene compared to 2D, and you will definitely need a bright display to compensate. The ASUS displays are excellent in this regard and much brighter than the ViewSonic display because they need to be.
Using a 120Hz display means that the monitor can refresh the image 120 times a second vs. the standard 60. With alternate frame sequencing, it happens so quickly that the brain merges the images together creating the 3D effect. The downside is that the eyes are now only seeing the image 1/2 the time, so the image looks dimmer than usual so you have to really increase the display’s brightness.
Some sensitive users report headaches simply from the opening and closing of the active shutter glasses. This is not an issue with passive polarized glasses since the lenses are always open.
The Software and Support
First of all, one needs to realize that the ecosystem that Nvidia has developed for 3D Vision is far more robust than other solutions for gaming. ViewSonic uses the bundled TriDef 3D software for its passive 3D. We still have at least 60 PC games installed and here is what Tri-Def found by scanning our hard drive:
It only found a handful of games and any other game that we wanted to add, we had to add manually. There are over 400 games supported in 3D by the TriDef software but it is not intuitive like with 3D Vision where almost all of the work is done automatically by the driver. Fortunately, TriDef has active forums where the users help each other and can also get help from TriDef reps in working around issues.
As you can see above, there are plenty of hot keys provided by the software. We played through quite a few games in our library to get a feel for passive 3D but are going to stick with Resident Evil 5 as an example of decent quality S3D with both TriDef and 3D Vision software. And we played with a HD 6970 as well as a GTX 580 to see if the experience was any different. It wasn’t. We also used a HDMI 1.4a cable as well as DVI; the HDMI cable has the advantage of carrying the audio to the display’s built-in speakers.
The TriDef 3D software suite is a relatively easy way to experience S3D. It will even convert 2D photos and videos into 3D but you won’t get the kind of effect that you get with actual 3D footage. Gaming with TriDef 3D is more complicated than gaming with 3D Vision. If the TriDef software scan does not find the games you want, you have to add them manually. TriDef software has predefined 3D profiles for many games that you select from a dropdown list. When a game is not listed as many of ours were not, we had to check out Game Profiles forum on TriDef’s website.
With the profile installed, the game is launched from the TriDef’s Ignition or from the user’s own self-created shortcut. It is generally more work than simply clicking on the game shortcut and having Nvidia’s drivers automatically handle everything.
The above image was taken partly through the polarized lens of the clip on 3D glasses. Let’s look closely at a small part of this scene also through the polarized lens.
If you look even not so closely, you can see that every other horizontal line of resolution is missing. That is how the 3D effect is created. Each eye gets 1920×540 resolution – the right eye getting a different view than from the left eye. It is rather obvious and very annoying to someone who is used to the full 1920×1080 resolution to each eye with 3D Vision. The only advantage that the passive display has, is that the image isn’t darkened as much as with the original 3D Vision.
Most gamers will have no issues playing first person or third person shooters and the Left 4 Dead series looks quite good. However, with half of the vertical lines of resolution missing, RPG players or players playing games with a lot of text may have issues with its readability.
Worst of all, with this kind of passive 3D, the player is locked to a very specific body and head position. If you move your head very much while playing, you will get all sorts of visual artifacting. And it is very important to sit at the right distance from the screen; about a yard away seemed to be the best distance for the overall best 3D effect.
Performance Issues
There is a common issue of framerates taking a significant hit when 3D in enabled with passive 3D or with 3D Vision’s active shutter method. Here is what you can expect playing Resident Evil in DX10 with fully maxed settings at 1080 with a Core i7-920 at 4GHz and a GTX 580 in regular 2D:
Not bad. 138.6 FPS average in the variable benchmark. Now let’s play it in 3D using TriDef’s software:
It could be that VSynch is being forced by the TriDef drivers as we are now averaging below 60fps – 56.8 – with the same system, the only difference is that we are playing in S3D. We got a similar slowdown with our HD 6970.
AMD’s HD3D
We asked AMD about HD3D and the ViewSonic V3D231, and about HD3D in general. At the time, they hadn’t yet received one for testing.
There are a few ways to send S3D signals to this monitor. The most obvious method is to use HDMI 1.4a. This is more of a plug and play method, as our driver will detect the HDMI 1.4a capability and expose our Quad Buffer to the application or middleware. In this format the driver sends a full resolution ‘framepack’ signal across the HDMI connection, and then the monitor takes that signal and converts it to a line-interleaved format for display on the panel. The drawback of this solution is that you are limited to 24Hz per eye at 1080p over HDMI with this monitor (but can do 60Hz per eye at 720p).
The other way to do it is to force a specific format over DVI or HDMI. This method is less plug and play for most users because they need to have knowledge of the format that the display supports (eg. Line interleaved, checkerboard, side-by-side, etc), and then make a corresponding setting in the S3D software they are using. In this case, we know that the monitor is line interleaved, so we can make this setting in TriDef middleware output options.
Deus Ex: Human Revolution is a very good looking game in S3D and we asked about it also:
For Deus Ex, TriDef middleware is not needed for Stereo 3D as it is one of our first native HD3D titles. This means that the game renders the left/right image pairs and hooks into our driver directly with our Quad Buffer API. So if you launch the game outside of TriDef using an HDMI 1.4a connection, the Stereo 3D option should show up in the game. Deus Ex also has support for a limited number of line interleaved monitors, but they do this by EDID detection.
We were interested in OpenGL titles which are not supported by 3D Vision:
Regarding Wolfenstein: this is only supported by iZ3D middleware, and only in line interleaved mode (no HDMI 1.4a). We plan to expand OpenGL support in the future.
Finally, we wanted to know what the HD 7970 brought new to HD3D:
As for the 7900 series, there are a few things. First, it is the most power single GPU card on the planet. This is great for HD3D, because you are potentially driving twice the number of pixels (for full resolution 3D monitors). The increased video memory (3G) also helps here, especially if you want to turn up the quality settings while doing S3D gaming. Also on the hardware side, we’ve included support for ‘Fast HDMI’ – this is an improvement to the HDMI physical layer that increases bandwidth and enables 60 Hz per eye at 1080p on supported displays (you’ll probably see some at CES). The rest are driver level improvement that coincide with the 7900 series launch – support for HD3D in conjunction with both CrossFire and Eyefinity (a real enthusiast configuration).
We appreciate AMD’s feedback and comments. Well, we have completed our testing of the ViewSonic V3D231 with a strong emphasis on gaming and 3D and it is time to head to our conclusion.
Were you able to adjust convergence and separation/depth for the games w/ Tridef drivers? If not then it reminds me of AMD’s HD3D support that does not allow for some games to be adjusted at all from its super-shallow default S3D (about 2 centimeters deep) which is more like 2.1-2.2 dimensions rather than 3.0 full dimensions.
Yes, take a look at page 4 of this evaluation and especially this:
http://alienbabeltech.com/main/wp-content/uploads/2012/02/re5settings.jpg
There are plenty of hot keys. The 3D effect is very similar and each kind of 3D has its own supporters.