I believe the current “movement feedback” in VR is wrong and nausea inducing (which could be the intent to make it lifelike but I doubt it is a design choice). As a matter of fact this might be all related to another effect I find wrongly done.
When flying in 2D prior access to he VR, I’ve been noticing when there is turbulent air, the aircraft seemed to be oscillating around a certain point (say like the CG) while still travelling along a nearly linear path, whereas I’d expect the aircraft jittering along a non linear path, like sudden vertical cliffs and edges perpendicular to the path the aircraft is flying.
observed travel path:
NB: the cockpit seems moving but it is my camera which is moving instead. In the headset (through the lens shot), the cockpit is static and it is the whole world balancing around you in a perfect sinusoid and nausea inducing movement.
- the simulator seem to make the aircraft oscillating around the CG in order to simulate turbulence.
The aircraft is constantly translating and more importantly oscillating in a way which makes it feel like it is only rotating around its CG on 3 axis aligned sinusoidal.
The aircraft oscillations seem odd in 2D compared to XP11 simulated turbulent air for example, because the aircraft travel path doesn’t seem to be changing much.
In VR, because you can rapidly look around in a seamless way, you can perceive these oscillations much more than when looking around in 2D.
- the simulator seem to be moving the view point position and rotating the view direction to simulate G forces affecting the pilot head.
- the view point is constantly translating (axis aligned translations)
- the view direction is constantly changing (rotating around the view point)
I believe it is meant to give the illusion your head is affected by G forces, which is when the aircraft is suddenly moving up, you head goes down. It might give a certain illusion when flying in 2D but it is all wrong and nausea inducing when flying in VR.
In effect, when the view direction is rotating all of a sudden, you feel like the world is rotating around you in an unexpected way, whereas in reality, when your head is suddenly moving, your eyes are compensating rapidly to the change in order to keep looking at the same point you were looking before the sudden movement.
In VR when the world is suddenly rotating or moving around you in an unexpected way, you’re not only perceiving something is odd immediately but it is also nausea inducing
In general aircraft movements in the air mass should be reflected by the aircraft frame translating around the pilot and the view position translating with a lag (like a spring with dampener).
[2D,VR] Aircraft oscillations are too strong and not realistic only because of their amplitude. This effect should be tuned dow.
[2D] Aircraft movement illusion using the inverse head movement might need lighter spring to amplify the perception of a sudden movement, most of the perception comes from the cockpit moving around you.
[VR] Aircraft movement effect requires small lag (stronger spring) because in reality your head is not lagging so much behind the body movement (let alone it would break immersion entirely) and most perception of a sudden movement perception comes from the world around you.
[VR] Head rotation due to G forces should be limited in VR because it changes view direction. Your eyes are compensating naturally.
[VR] Head movement due to G forces should be limited to very small distances (see above aircraft movement).
[VR] When in external view, the camera shouldn’t oscillate as it does in 2D (this is an effect which makes the aircraft on the ground oscillating due to wind and this is making the VR camera bouncing around in all directions)
Here is a compilation of Unity VR Best Practices and whether FS2020 is implementing them: