In flight simulation, the environment is usually transmitted via a screen or TV monitors. This creates a physical effect. What is straight for one pilot is crooked for another. The pilot steers the aircraft in a dead straight line on the taxiway and the co-pilot throws up his hands in disbelief.
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Why is that? The effect is created by the pilot and co-pilot looking at the projection screen from different angles.
How strong is the effect in practice?
The effect is greater the smaller the distance to the screen and the smaller the diameter:
Projection Area with 4.0m diameter.
Projection Area with 5.0m diameter.
Projection Area with 8.0m diameter.
The effect is particularly pronounced with TV monitors, as these are usually positioned very close to the cockpit for space reasons. If three monitors are used, a lot of thought should be given in advance to what the lines of sight will look like. In this example, the line of sight - and therefore the runway(!) - would be exactly at the edges of the monitor.
What can you do about it?
By the way, an oversized screen is usually not the answer. From a certain distance, the required height of the screen becomes a problem. The simulator must be placed on a platform. There are also a whole series of other problems.
If you have the space for it, you are well advised to use the largest possible screen. However, if you don't have the space, you don't need to worry either.
Switchable Views for CPT and F/O
The solution is to have two switchable views that are switched to the respective Pilot Flying (PF).
In MSFS2020 we have made the appropriate settings in camera.cfg. Essentially, it's about the values of InitialXyz and InitialPbh. You can find very good tutorials for this on Google.
Te best way to evaluate the correct values for the camera settings is by trial and error. Place the aircraft on the runway and then find the correct values by trying out different options. For you orientation. The runway centerline should be between PFD and ND.
How do the professionals do it?
Of course, even professionals can't change the laws of physics. But they have a little more resources than we do. :-) The answer is called Colimated Display.
Technical Background
During our research on the subject, we came to the conclusion that the term "parallax effect" is not being used correctly in our context.
According to the definition, the parallax effect influences the depiction of the surroundings from the cockpit in order to convey a realistic feeling of speed and distance. It is created by different speeds of movement of the elements in the scenery.
Nearby objects move faster than distant ones, which is simulated by the animation of different levels in the simulator. This reinforces the illusion of spatial depth and improves the realism of the simulator experience.
So far so similar. But we don't know of a better term.