MSFS is breaking the VR golden rule: don't move the camera, the user is

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.

Two issues I can observe:

  1. 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.

  1. 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

Suggestions:

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)


[22SEP2021]

Here is a compilation of Unity VR Best Practices and whether MSFS is implementing them:

I’d like an option to have it on. I don’t get motion sick from VR anymore, but i know that lots of people are.

Same goes for the movement towards the dashboard when using VR Focus (zoom), it should blank out when moving the camera to ease the differentiating movement the eye perceives and the inner ear balance sensory discrepancy which causes nausea. Give us options, don’t just force this on everyone.

As an comparison: The otherwise excellent “Elite Dangerous” have taken away VR from the new upcoming expansion and put in a 2D representation for VR players because of some people being nauseous, but everyone isn’t getting nauseous and we still like to experience everything in VR since going 2D is kind of ruining the whole point of playing Elite which is THE best VR experience around for lots of people.

Asobo, don’t be like Frontier Development, give us the OPTION to turn things on and off.

5 Likes

I don’t either until you’re encountering this weird experience I’ve had lately: flying the CJ4 from LIMC to LFLL and once at 30000 above the Alps, the simulator wanting to show me there is turbulent air is violently making the whole world around the aircraft oscillating like a pendulum at a 1hz frequency, with angles as big as about 5 deg. This means you’re looking straight ahead and the horizon line is moving up and down by ± 5deg repeating this in a perfectly perceivable pure sinusoid repeating at 1hz… Look side ways 90deg and then you have the illusion being in a boat with the entire ocean moving around you…

The reason for this is because instead of shaking the aircraft path, they’re most likely moving the world actually. It is cheaper to implement, works nearly the same in 2D because you don’t have the perspective and focal length to perceive this, and this is fine for the most part implementing cheap game tricks to give the illusion (well it didn’t give me the illusion in 2D either where I could already sense the aircraft was oscillating around it’s CG more or less in a sinusoidal fashion). But in VR it is absolutely not the way to do. By comparison, I find XP11 simulating the aircraft shakes due to turbulence well done both in 2D and VR.

6 Likes

Just want to add to this: it also seems like the rotation center of the VR view isn’t quite in alignment with the center of the headset as it should be, in the Oculus openXR runtime at least. This causes slightly disproportional movement, e.g. turning your head 20 degrees causes a slightly larger change in the VR view. I haven’t figured out any way to prove this exactly, yet – but this is what it feels like to me and I’vev spent several thousand hours in VR in other flight sims and games over the last 3 three years, so I know what ‘correct’ head tracking feels like.

@SwirlyMaple7 I confirm I’m noticing this as well with the G2, nearly not with the Index. I was attributing this to the superior tracking technology of the Index but it might as well be something FS2020 related.

1 Like

Thanks for the confirmation. I had a bit closer look at it a few minutes ago, too. I think it’s better described as a very subtle projection distortion, where head movement is slightly changing the scale and curvature of things in your FOV. It’s very subtle, but if you look at a fixed surface in the cockpit and rotate your head up and down, the cockpit geometry warps a tiny bit with it.

I realize this is unavoidable to some extent in VR, since lens distortion can’t be perfectly compensated, but the amount I’m seeing is significantly more than other VR apps do this, with the same headset. And if you set the openXR runtime to Steam instead of Oculus, head movements cause a huge distortion of the nearfield, like the world view is being stretched by rubber bands attached to your head when you look around. Since I haven’t seen this in any other apps, I suspect it’s a problem with the openXR implementation, since this is a pretty new thing and very few apps are using it at this point in time.

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Simply put: MSFS should shake the airframe and not the world when simulating turbulence.

This is something MSFS should copy from other VR flight sims right away.

14 Likes

and, whether 2D or 3D, give the user some control over the amount of the shake turbulence effect.

Not all planes get shaken around like a Piper Cub !!!

I find even the C172 is far to shaken, by even the slightest wind gusts, which is totally unrealistic, – to such an annoying extend, that I often end up removing the wind, just to get rid of the annoying, fake motion,

5 Likes

About nausea and headache more generally, I hope they’ll add something like Ultrawing’s nausea reduction features: Options to black out all windows except the one you’re looking right at. Option to artificially reduce the windows size, with black borders.

This can help a lot. Try it. If you experience nausea/headache in planes with big windows, like the DV-20, Cub, etc, then try flying one of the pressurized planes like the TBM, or better yet the 747, with their smaller windows. Far better. (I can only fly the Tie Fighter in Star Wars Squadrons VR, for similar reasons)

Or like movement in, eg, “Walking Dead Saints and Sinners,” where whenever you move, it blacks out your peripheral vision, leaving only a small-ish circle (tunnel vision). Returns to normal the instant you release the controls. This can help a lot for those of us who experience nausea.

I’m sure they’ll get there in future updates. Shouldn’t be too much to ask, to match the feature set of a $10 arcade game like Ultrawings.

This sounds like a proper solution.

4 Likes

I will make a big second (and third and fourth) to dealing with turbulence. In 2D I’m ok with it, but in VR it definitely shortens the amount of time I can comfortably use it. I’ve actually gotten past the point where I don’t get sick from this sort of thing, but combined with the already low framerates, it produces extra blur, discomfort, and eyestrain. And it doesn’t feel like real turbulence to begin with. I actually DO like the feel of getting blown around a bit (something I recall disconcertingly from back when I took flying lessons in real life), but the turbulence in VR just feels like driving on an incessantly bumpy road, and there needs to be an option to turn it both down or off!

1 Like

5dof motion rig user here. We need the option to turn off all types of “head shake” as we are getting it already via the rig.

Thanks.

4 Likes

Agreed. Very annoying. Head bobs relative to the cockpit, cockpit moves relative to the ground…all while no input from organic gyros. Makes me dizzy.

In FlightSimulator.cfg edit this section to:

[DynamicHeadMovement]
LonAccelOnHeadLon=0.00000
LonAccelOnHeadPitch=0.000000
RollAccelOnHeadLat=0.000000
YawAccelOnHeadLat=0.000000
RollAccelOnHeadRoll=0.000000
MaxHeadAngle=0.000000
MaxHeadOffset=0.000000
HeadMoveTimeConstant=1.000000

The head movement goes away.

10 Likes

Are you sure this is also working in VR?

Because in FS2020 VR mode what I see is the head relative to the aircraft depends on your headset tracking, but the whole aircraft moves with you onboard without compensating and in turn causes the whole world moving around your head, making you dizzy.

OMG – Thank You

For the past 4 months i have been flying in MSFS like I was a Bobble-Head, !!
Got rid of the Overly Excessive “Head Movement”, and now Flying in MSFS is so much more like RL.

Thank You …

1 Like

Try it and let me know what you think, but in VR, seems to work for me also.

I flew the x-cub, held my head straight relative to the top of the console and relative to my chair IRL…rocked the ailerons and wagged the rudder, and couldn’t sense any head movement relative to the console. Outside world moved of course.

Maybe but this is not the point.

  • Are you flying in VR too ?
  • Have you read the rest I’ve written past “Are you sure this is also working in VR?” ?

In VR, the head MUST move relative to the aircraft so that it is FIXED vs the world, not vs the aircraft. This is the premise. From then, instead of fixed vs the world, it much be moving along the aircraft in a dampened fashion because IRL, the aircraft moves around you first, and you catch up the movement with your body later, and during this time your eyes are keeping the same outside reference by reflex.

3 Likes

Yes I’m flying in VR. For me it’s better without dynamic head movement, YMMV.

Without dynamic head movement, the headset orientation (relative to the room) sets the view relative to cockpit. Outside view still moves around as expected.

With DHM, view relative to cockpit is set by headset orientation plus an adjustment based on cockpit acceleration vectors (lateral and angular).

I like it better without DHM.

2 Likes

After careful consideration I have determined that this message may be in violation of the guidelines, so as a precautionary measure it has been removed.

msg 344861/20

1 Like

I have no idea what the entries in the simulator.cfg really do, but the effects are noticeable for me at least. If I put them all to an extreme value (like 999) and then fly it’s pizza on the walls. Reverting them to zero reduces the pizza-effect greatly.

No it isn’t the solution nor even a solution to the underlying problem - which is the world shake.