The Problem with Using Three Monitors


After the "wow" factor passed, I've discovered an issue with using 3 monitors and the TripleHead2Go.  This issue exists even without  using 3 Fresnel lenses.

Many people think that the frames around the monitors will interfere because they break up the picture.  Actually, I think they are easy to get used to.  The problem I've found is that objects "hop" or "pop" from one screen to another rather than moving smoothly.  This is because the objects don't go "behind" the monitor's frames, but in a sense, jump over them.  This also causes timing issues as things come into view before you expect them to.

Here is an example of a static view.  Picture 1 shows what we expect to see.  A row of equally spaced cones.  The ones obstructed by the screen's frames are behind the frames as they should be.  Picture 2 shows what we really see in a 3 monitor setup.  The large virtual screen is spread out across the monitors leaving a void where the frames are.  The problem is not that you don't see anything in the void, the problem is that there is nothing in the void.  In Picture 2 the cones look distorted and not equally spaced.  This may look minor in this example but it is very distracting in practice.

Cones

Here is an example based on time.  I am showing 2 monitors here to make the example simple.  Here we compare what we expect to see and what we actually see at time(t) intervals.

Circles on screen demo
At t1 the circles are on the right hand monitor start moving to the left.

Circles on screen demo

At t2 the circles have moved to the left.  We expect the first circle to be behind the monitor frame, but it already shows up almost completely on the left monitor.

Circles on screen demo

At t3 the circles have moved a bit more to the left.  We expect only half of the circle to be on the left screen, but it shows up as completely there.  Our eyes and mind adjust to where it is shown (100% on the left screen) rather than where we predicted it should be.  Should the circles move back toward the right, another "jump" will happen and we will have to re-adjust to that.


Possible Solutions?

  1. You can overlap your monitors but you have to do more than overlap the frames.  You need to actually hide part of the screen for a smooth transition.  The problem with this is that one monitor has to go in front of the other.  This cause bad alignment problems between the images as the monitor that is closer looks bigger.  
  2. You can adjust the horizontal control on your side monitors.  For example place the monitors together (not overlapping). On the right side monitor, use the horizontal control to push the picture over to the left.  The effect is that you are pushing it "under" its own frame and under the center monitor frame.  If there is enough adjustment (2 times the width of one monitor frame) you should be able to get it perfect.  Do this with both side screens.   I had to play around with other options such as making the center screen wider because I didn't have enough horizontal adjustment.  Although the monitor frame area is big due to being side by side, if you can get it adjusted correctly at least you don't have the distortion of having one monitor in front of the other.
  3. Using a TrackIR helps because as you look to the side, your view is drawn toward the center monitor and away from where the monitors meets. This doesn't negate the benefit of 3 screens because they still offer more immersion due to filling your peripheral vision and because you can still look at the side monitors.
  4. If you can deal with the down side of the Fresnel lens on a 3 monitor system (the focus of the edges between monitors is a bit strange), you can use them to blend out the screen frames so as the image moves from one screen to the other smoothly. Combine this with a TrackIR you get the benefits of the Fresnel lens and minimize the down side.

Future Solutions?
  1. It would be great if the TripleHead2Go had the equivalent of a horizontal adjustment so you could use that instead of those on the monitor.  I don't know if all monitors have sufficient adjustment but building it into the TH2G could guarantee a wide enough range.
  2. Simulator programmers could put this 3 screen mode in their programs with and an adjustable "frame width" that could be set by the user.  I imagine this would put a heavy burden on the graphics system however.
  3. How about monitors without frames?  They should be separate though so we can curve them in as much or as little as we want.

Other ways of increasing the video experience?

Of course one big monitor solves the above problems, but a big monitor can't be curved in at the sides to fill more of you peripheral vision.  Also, big monitors usually cost more than a 3 monitor plus a TH2G system.  This is especially if you already have one monitor you can use (you only need to buy 2).

Projectors should work because there would be no frame to deal with.  Actually, the 2 screen version of the TH2G (DualHead2GO) may work with 2 projectors without the cost of 3 projectors.  As long as you can position the 2 projectors to get rid of the "seam" in the middle.  It may even be possible to angle the two projector screens inward.

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