Adjusting View Angles and Zoom Settings on Multiple Monitors

18.04.2019

Setting Up and Alignment of Outside Views On Multiple Monitors

Turning a knob on an instrument cluster certainly beats mouse clicks on a computer display. But in my opinion the biggest step towards immersion in a simulation is the increase of the Field of View (FoV). Seeing more of the simulated outside world has several positive effects:

Better situational awareness
Everyone who first used PC-based flight simulators and then took up flying lessons will agree: Flying a plane in realityis actually easier than doing it on the computer, because in the real plane you see so much more of the world around you. This is particularly true for landings. Judging the right moment for the turn into final is easy when all it takes is a quick turn of the head.

Better height and speed perception
Only a larger FoV makes the perception of lateral movement possible. The human brain mainly judges speed by analyzing movement in the peripheral field of view of the eye.

Less distortion
The standard Flight Simulator outside view looks like a photo taken with a wide angel lens. For an undistorted view, you must zoom in. Now the view is undistored, but the FoV is very limited. Here is where the display on two or three monitors comes in…

Multi-monitor Setups

There are several different ways of setting up multiple monitor outside views. Some are for commercial purposes and financially out of reach for humble cockpit builders. But others are rather easy to set up. Here are tree solutions that I have tried successfully:

WideView by Luciano Napolitano
Commercial program, one PC per view, each PC runs it’s own copy of Flight Simulator. All PC’s must be networked. Advantage: high frame rates, because each PC/video card renders only one outside view. Disadvantages: Clouds and AI aircraft are not properly synchronized, at least not in the FS9 version; high cost for hard- and software.

Multiple monitors connected to one PC
Today’s video cards usually have two video outputs, so the connection of 2 monitors is easy. With SLI or Crossfire systems up to 4 monitors can be connected. The latest mainboards even come with 4 PCIe slots, so theoretically a total of 8 monitors is possible. For multiple outside views on one PC, the CPU (which must calculate ALL views) is the limiting factor. I found that three full window outside views, each on it’s own monitor, is the maximum number that even a fast machine can handle. Max. fps will be in the mid 20s, but can go as low as 10 in dense scenery.

Matrox Tripple Head 2 Go (TH2G)
The TH2G is an external box that is plugged into the computer’s video card. It has digital output connectors for 3 monitors or beamers. The PC “sees” the TH2G as only one very wide monitor. This allows single window output of the MSFS image (one FS window is better for frame rates than two or three). The PC output is split by the TH2G into three video streams and sent to the monitors. The TH2G is simple to set up and provides very good performance.

Physical and displayed Field of Vision (or: how to get the perfect outside view)

There is a difference between the physical FoV for your monitor and the FoV that Flight Simulator displays. The physical FoV is defined by the distance between pilot and monitor, and by monitor size. Even a 31″ monster monitor might only produce a physical FoV of 5 degrees, if you sit 5 meters away from it. As another extreme, a tiny 14″ monitor could produce a huge 120 degrees FoV, if you just get close enough. Compare the monitor to a window: The closer you get to it, the more of the outside world becomes visible.

Flight Simulator, on the other hand does not know the size of your monitor or your distance from it. The portion of the outside world displayed by FS is simply defined by the zoom setting. Usually, FS uses a default zoom factor of 1. On a single 3:4 monitor that produces a wide angle image with a FoV of around 55 degrees, independent of monitor size. The trick is to find out the actual, physical FoV of your cockpit setup and than adjust the zoom setting inside FS accordingly. Here is how to do it:

Step 1 – Find out the physical FoV of your cockpit setup

Make a scale drawing of your cockpit. Include the exact dimensions of the visible monitor area, the monitor’s frame and the distance between your eyes and the monitor. Make sure you measure while in your regular flight simming posture (head proudly raised, shoulders straight – you get the picture…).

If done with precision, this drawing will tell you the exact field of vision (FoV) per monitor, in degrees. Equally important, it will give you the FoV – also in degrees – of the space blanked out by the monitors’ frames. Adding these numbers for all monitors in your setup gives you the total physical FoV in degrees.

For reference, see the picture on the left.

Step 2 – Find out the FoV that Flight Simulator is actually displaying

Set the sim to the view normally used for flying (in my case this would be full outside view, no instruments). Press shift-z to see attitude and position information on the top of the screen. Look for the heading in degrees. Using the slew function or the joystick hat switch, pan the view until a far away object like a building – the moon also works fine – lines up with the left edge of your screen. Write down the heading of the airplane.

Now, pan to the left, until the same edge of the same object lines up with the right side of the screen. Take note of the new heading. Now just subtract the first heading reading from the second and voilá: you found the displayed FoV corresponding to your present zoom setting!

If Step 1 and Step 2 of this tutorial produce different numbers of degrees (i.e. different FoV), you need to adjust thre zoom setting in FS. The zoom factor must either be increased or decreased, depending on your setup. The goal is to find a zoom setting where your displayed FoV is identical to the FoV (i.e. number of degrees) calculated during Step 1.

The correct zoom factor depends on the type of setup: If WideView is used, each monitor must be adjusted individually; start experimenting with a zoom setting of 1,35 per monitor. In a 3-monitor TH2G setup on the other hand, the zoom factor must be reduced to around 0,35 to match displayed with physical FoV.

Adjusting pan angles with multi-monitor setups on 1 PC

Open as many outside views in FS as you have monitors. Undock each window and drag it to it’s own monitor. I assume that your windows desktop spans all monitors. Press Alt-Enter to maximize windows in 3-D accelerated mode. Now adjust zoom setting on all monitors to the value found in Step 2. Using the coolie hat of the joystick, pan the left and right windows until they look right. This step is best done while the airplane is parked on the tarmac, preferably with many yellow lines around for visual reference.

Once the result is satisfactory, save the flight. FS9 will remember the different windows and their view angle. Only the zoom setting seems to get lost, so it has to be re-adjusted each time you start the program.

That’s all there is to it. Now, enjoy your new panoramic view. I promise: flying FS will never be the same again!

Tip

In FS9, panning with the coolie hat of the joystick in the 2D cockpit only works after the following line has been inserted into the fs9.cfg file (make a backup first!):