3D on your PC


A large range of hardware and software is available to allow you to view stereoscopic 3D images on a PC. One common 3D viewing technique is to use a pair of Liquid Crystal Shutter (LCS) 3D Glasses in combination with a CRT monitor. (NB: LCD monitors are generally not compatible with LCS glasses - see below).

Technical Backgrounder

LCS 3D glasses rely on a sequence of alternating left and right images displayed on a monitor. This is called variously time-sequential, field-sequential, frame-sequential, or image-sequential. There are four main techniques of achieving time-sequential display with PC systems. Here's a quick tutorial if you are interested how these systems work:

(1)   Page Flipping

Page flipping is the highest quality method of producing time-sequential stereoscopic display. It is primarily used with non-interlaced (or progressive scan) displays (which display all the lines of the frame in one go, not half/half as in interlacing).

Page flipping works by flipping between two pages of video memory (of the video card) every time a new image (frame) is to be displayed. One 'page' will hold the left perspective image and the other 'page' will hold the right perspective image. The flipping can be performed by your video card's BIOS (the better solution) or a device driver could be installed which will watch the progress of the video card generating the video signal. The result is a sequence of left perspective image and right perspective image frames.


  • Your video card needs to support page flipping in the BIOS, or you need a resident device driver to do the page flipping.
  • Your video card memory will need to accommodate two images (the left and right) to allow the page flipping to occur. [not a problem with modern video cards].
  • Glasses hardware can be relatively simple
  • full vertical resolution.
(2)   Row-Interleaved Image + Interlaced Display

Interlacing is probably the easiest method and is what is used in (PAL and NTSC) 3D video systems (i.e. field-sequential DVDs and VHS video tapes available from various suppliers).

Interlacing means that first the odd lines of the image are drawn on the screen (the odd field) and then the even lines of the image are drawn on the screen (the even field). If the image is constructed of odd lines from the right perspective image and the even lines from the left perspective image, the interlaced nature of the display will mean that first a right image will be displayed and then the left image will be displayed (left and right images will be alternately displayed - time or field-sequentially). When viewed through LC shutter glasses synchronised with the field rate, each eye will see a different image.


  • Some video cards won't switch to interlace mode.
  • You only get half vertical resolution.
  • relatively simple software-wise to implement.
  • Hardware can be relatively simple
  • very easy to display stereo images by using 3D interlaced images (such as appropriately generated gifs)
(3) Sync Doubling

Sync Doubling (or sub-fields) works by dividing your existing screen into halves (the top half and the bottom half). Your software puts the left image of a stereo-pair into the top half of the display and the right image of a stereo-pair into the bottom half of the display.

After your video card generates its normal video signal, an external black box adds an extra vertical sync pulse to the video signal (at the vertical mid-point of the screen). The monitor will now see the video signal differently from before and will display the first half of the video signal (which used to be the top half of your screen) as a full screen image and then the second half of the video signal (which used to be the bottom half of your screen) as a full screen image. So again, there will be left and right images being displayed alternately (time sequentially). LC shutter glasses can be synchronised with these images to allow you to see a 3D image.


  • Half vertical resolution
  • Hardware is relatively complicated
  • Software needs to be smart to maintain compatibility with existing graphical user interfaces (like Windows).
  • images need to be squashed vertically before writing to video memory.
  • software is relatively simple (apart from compatability with GUIs).
  • you don't need a high speed video card to display flicker-free stereoscopic images.
(4) Line Blanking

A row-interleaved 3D image is displayed by the video card in progressive-scan video mode (i.e. not interlated-scan). A dongle plugs into the VGA port of the computer and the monitor plugs into the back of the dongle. The dongle actively blacks out alternate lines of the video signal. In the first frame it blacks out the odd numbered lines, and in the next frame it blacks out the even numbered lines, and this sequence then repeats. The video signal will then be an alternating sequence of left and right "frames". The dongle usually also drives a pair of LCS glasses.

The line-blanking method could be seen as a method of converting a progressive-scan video signal to interlace-scan, however the resultant video signal is still progressive-scan, it's just that the relevant lines have been blacked out.


  • Half vertical resolution
  • Dongle hardware is relatively complicated
  • relatively simple software-wise to implement.
  • can be used with video cards which won't switch into an interlaced video mode
  • very easy to display stereo images by using 3D row-interleaved images (such as appropriately generated gifs)

There are some animated GIFs at the Catalyst web site which beautifully illustrate the operation of the first three of these systems. If you are having problems with my descriptions, check out the images.

  interlacing: http://www.frostbit.com/Catalyst/interlace.html
  page flipping: http://www.frostbit.com/Catalyst/pageflip.html
  sync double: http://www.frostbit.com/Catalyst/syncdouble.html#syncdouble

NB: Some of their descriptions are a bit wrong in places and exhibit a bias towards the sync double technique which I guess is understandable because their system uses the sync-double technique.

Systems and the Techniques They Use

To my knowledge the following systems support both the interlace and page flipping methods: 3D-MAX (Kasan Electronics Korea), VR Surfer (VREX) & Simuleyes VR (StereoGraphics), 3D-SPEX (NuVision)

The systems from 3DTV corp use the page flipping method (but there is nothing technical stopping them being used with the interlacing method too)

Neotek uses the sync-double technique.

The VR Surfer (VREX) also supports line-blanking.

A comprehensive list of 3D LCS glasses is available here:


I've avoided the topic of flicker so far because it is a bit more complicated to explain than it first may seem.

The following table illustrates what happens with the various 3D display methods with regards to image refresh rates: (borrowed in part from Catalyst's web site)

3D MethodVertical Output Frequency
of video card#
Fields per SecondEffective Refresh Rate
for a Stereo Field Pair
Vertical Resolution
Page Flipping60Hz60Hz30Hzfull

# 60Hz is the standard VGA output frequency (vertical frequency, images per second). Most video cards will accommodate much higher frequencies. All of the figures in this table will be different for a higher/different output frequency.

Here's a modified version of that table where a 120Hz update rate is required:

3D MethodVertical Output Frequency
of video card#
Fields per SecondEffective Refresh Rate
for a Stereo Field Pair
Vertical Resolution
Page Flipping120Hz120Hz60Hzfull

Now the ifs and buts:


There are now video cards available which perform hardware page flipping. That is, there is no need for a resident device driver to manually flip video pages - it's all done by the video card. These cards also sometimes have a socket for a pair of LCS glasses. The first such card was the "Canopus Total-3D" card but it is now out of production. Fortunately there are now other cards available, e.g. most video cards from nVidia.

See this white paper:
  nVIDIA "3D Stereo Technical Brief"
  www.nvidia.com/object/LO_20010605_6971.html (271 kB pdf)

Compatibility of Display Types with Time-Sequential Display

As mentioned in the introduction, LCS 3D glasses can be used with CRT monitors, but not with most LCD monitors. This is mostly due to the low pixel refresh rate of LCD monitors (and the lack of a blanking interval).

The following paper goes into substantially more detail on this topic and lists other types of displays which are compatible with LCS 3D glasses:

Woods, A.J. (2005) "Compatibility of Display Products with Stereoscopic Display Methods", in Proceedings of the International Display Manufacturing Conference 2005 (IDMC'05), ISBN 957-28522-2-1, Taipei, Taiwan, 22-24 February 2005. (39kB pdf)

3D Image Gallery

A Gallery of 3D images (in various formats) is available here.

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Last Updated: 11 June 2005
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