Compulsive smooth / motion smooth etc

I guess these are methods of providing judder free gameplay when fps is low, but i dont fully understand how to use them. Ive only tried compulsive smooth at 1/2, 60hz, in msfs, and noticed no difference to smoothness to when all smoothing is off. Fyi i get an average of about 30 fps in msfs when all smoothing is off.

Its not a bad experience at 30fps. In heavy load scenery fps drops to mid 20s, then its juddery. Tell me, what smoothing options and refresh rate i should use for maximum smoothness? But i know smoothing produces visual artefacts so idk if i’ll stick with it. Remember, i only get 30fps average.


Wish to hell we could tell you.

We’ve played with the 1/2 @ 90hz in SkyrimVR; it actually made our repro worse but the motion smoother? Can’t quite describe it. What little benefit we got was outweighed by the ‘stillframe’ effect when swinging our head from side to side.

Tried the same with the 1/3 and it was even worse.
So, we keep it in the ‘Close’ position (off).


Ah ok no problem, thanks for the info.

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I wish I can find more detailed info about compulsive smooth. All what I saw is in release notes of Pitool 272 beta:

1. NEW Feature - Compulsory smooth option. This is a locked frame rate option. It can be set to a half or a third. It caps the frame at a portion of the overall framerate. For example, if you set the headset to 90Hz, one-third mode will cap frame generation at 33 FPS and half will cap it at 45 FPS. This can be enabled with or without smart smoothing.
2.This enables smooth operation in the most challenging scenarios.*

What does it mean? As I understand that is nothing else then way to set refresh rate not only to 64Hz, 72Hz and 90Hz, but also to 21.3, 24, 30, 32, 36 and 45Hz.

Full Hz ´1/2 HZ ´1/3 Hz
(114) (57) (38)
90 45 30
72 36 24
64 32 21,3

Each of these refresh rates can be used with smart smoothing, which halves refresh rate further.
I.E. If I choose 90Hz with 1/3 compulsory, that is on end nothing else but refresh rate 30Hz. If I add smart smoothing for it, then in graphic heavy environments I can have “real” refresh rate 15Hz with 1 additional frame interpolated between 2 real frames.
(Special case would be to force motion smoothing all time, and this is important feature, but leave it for now).

Why would anybody want that? Well for regular gaming, and for better hardware that does not make much sense. Pimp your refresh all way up and enjoy :slight_smile:
But in some special cases that can be useful also. I think about slow games, without much movements, like civil flight simulators (MS Flight Simulator 2020), or maybe for watching a 2D movie in VR. Then you can pimp your graphic at cost of reduced refresh.

It would be much better to have compulsory from valve index, there user can choose high refresh, and set not 1, but 2 or more interpolated frames between 2 real ones. I was hoping Pimax compulsory is the same, but it is not.

I was reading before that 90Hz is minimum for not getting sick in VR. That was the truth for older goggles with less resolution, but not any more. Now modern VR goggles have 9 million pixels per eye, and in slower or regular games that is enough to trick you into being in a game without proper 90Hz. I play mostly with 72Hz (8kx), what was sh*tty on oculus rift.
Only for quick games refresh rate must be still high (beat saber, ping pong, fast shooters).

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Thx for the detailed reply! So, from what i can gather from your reply, i can try compulsive smoothing at 1/3 with msfs 2020 and it should run at 20 fps (as my refresh rate is 60hz) and be smooth? I will try it.


Hm, 20fps can not be smoother then 60Hz. But there is something else in whole package. For 1 frame in 64Hz your pc has 1/64Hz = 15.6ms to create 1 frame. If he can, that is excellent. But if its struggling, then you may consider going down with refresh. The trick should be to go lower and lower, untill your pc has enough time to create next frame. For your case that would be 46.9ms ( = 1/21.3Hz).

Motion smoothing gives almost double time for creating 1 frame, but with some errors. Sometimes it helps.

You may try in your game also fixed foveated rendering. It works good on some games, and I like it.


Well i tried compulsive smoothing 1/3 and 60hz refresh rate and it was very unsmooth. fps was locked at 20 so it was ‘working’ but the result was very juddery.

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About the best explanation of this found so far. Thanks, BrziJoe.
Also makes sense why we got the effect we did.

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