The online racing simulator
Severe Lack of Smoothness in VR
(61 posts, started )
hear at least thank you because I do worse than you, I am about 5-15 depending and play in version 0.6E because the last one is super super bad, we would talk about about 1-5 nightmareFrown
Quote from rapapar :Hello,
I have the same issue, I really love LFS and my 980ti i5@4.4Ghz can runs it at hundreads of FPS, but I have headacke after 5/10minutes because of this laggy style fx Frown
I'll try to lower FPS to 50hz anywhere in the config.

Thanks to dev team to take time to answer us Smile

must be something set incorrectly, mine seems to be running good, occasionally it falls below the fps which it is locked at for vr but it is not often Smile
I tried the game again yesterday. Still stutters in vr . Locked at 90fps on rift the whole time
Sorry to hear about your issues.

I've had a few stutters myself. Can last from 10ths of seconds, up to few seconds. But at worst, only a couple of stutters per game session.

A stutter for me is when game freezes, then restarts. Problem of course, is you're driving during that freeze, so you could have driven into a wall instead of round a corner during that freeze.

However, most of my sessions I haven't had single stutter.

Maybe it's not a Rift issue.

Maybe the fact that you need 3 x USB3.0 connections just to run the Rift. That, and like me, you've probably got other USB connections for peripherals.

Me, I've got separate USB connections for a mouse, keyboard, wireless dongle, external speakers and G25 wheel. Unfortunately, my mouse and keyboard aren't a set so I need different usb receiver for both.

And I've got both my Rift and my tv connected via HDMI to my single graphix card.

A fairly expensive way to test if possible usb issue would be to buy a powered USB3.0 hub, and plug the Rift and sensors into that, and plug the hub into a USB3.0 port on your pc.

Longshot - if you knew someone else who had a Rift, and tried theirs, just to see if you have bad headset.

I've just looked at the video I made "Armco Canyon" that I put on Youtube, but not a single thing wrong that I can see anywhere, although to be fair, it's a very short video.

Can you record what you're seeing on the Rift? If so, does the recording look better that you're seeing on Rift? I use Plays.tv to record LFS. Can be set to record every session automatically. Or maybe look at spr replay?
So Iv tested it with another rift , it’s def the game . My other sims work flawless. I’ll try to do a through the lens tonight.
Quote from hot00frb :So Iv tested it with another rift , it’s def the game . My other sims work flawless. I’ll try to do a through the lens tonight.

How can it be the game if it works for others better than it is for you ?. The only thing we have different is hardware and how the system is setup. Do you have steamVR or steam running in the background as that can greatly mess with the fps ? Also your refresh rate and FPS should be lock by LFS when your in VR mode

The only real time i suffer a freeze for a ms or 2 is sometimes when someone joins the server or leaves the pits but that has also been noted by some non VR users
I normally play assetto corsa , pc1,pc2 and race room. all work perfect in VR. some use oculus and some steam VR. I downloaded LFS recently and since day one it’s stuttered. I only use oculus with LFS no steam VR. The game is locked at 90fps and verified it’s running at 90fps . After I first downloaded it and noticed the stuttering I took to the internet after trying settings first thinking it was that. That lead me to this post with other users having the issue as well. I have yet to find a solution despite searching the net and seeing people suffering from it. Not sure why some works fine some the game is un playable (like mine)
i play exactly the same games and all work very well, LFS running much better than the others in VR for me though.

Do you get the same problem if you try hotlap or single player mode ?
Hot lap actually worse than single player . I think I’m gonna try uninstalling the game and reinstalling it.
Deleted and reinstalled ,still have issues . If I’m sitting still or moving straight it’s lretty much fine but the min I turn at all even a slight turn it stutters bad
ah so its not to do with connection to the server or anything, there is a button which brings up some info that shows physics ect update which should give some insight, il have to take a look now then il post the key to press to show it Smile

EDIT - Go to settings and then misc then on the right hand side at the top click the + sign and it should show sleep phys wait . how do they look when you go to drive or turn ect.
The "Sleep" column is the sleep milliseconds that are used for frame rate limitation. This takes place at the start of the game loop, before the physics updates. Also if "Sleep every frame" is set and there is no other Sleep or Wait then there will be 1 ms Sleep shown in this column. If you use frame rate limiting then you will normally see something in this column. Sleep is time deliberately given up to the operating system each frame because LFS doesn't need to do anything.

The "Phys" column shows the number of physics steps calculated in the frame, before moving onto drawing the visible representation of the game state. These are the physics steps that represent 0.01 seconds of game time. So if you have frame rate limited to 100 Hz and you are not paused then you should see one physics step per frame, which will look like a solid vertical orange line. (This column does *not* show milliseconds)

The "Wait" column is the number of milliseconds of Sleep while LFS is waiting for the GPU to finish rendering. If you do not limit frame rate then you may see something in this column. In that case you are more likely to see something if you set "Maximum buffered frames" to zero. LFS is then waiting for the GPU to finish before starting to render a new frame. If you use buffered frames then it may be you do not see anything in the Wait column. You should not add more buffered frames if there is no waiting, because it that case you would just be adding lag. If you use full screen vertical sync and you are in full screen mode then you will see Wait. In this case you are waiting for the GPU to present the image to the screen, just in time for the monitor refresh.


I wouldn't advise triple buffering.

I think you can use a frame rate limit if you like or vertical sync if you like, but in any case, do not allow more buffered frames than you need. They will add lag if you add more than the number that increases your frame rate. I guess for most people, 1 buffered frame should be the best. Old LFS had the equivalent of 0 buffered frames. It's still possible that 0 buffered frames is best, to reduce input lag, if you are using vertical sync and you never drop below your monitor refresh rate.

With buffered frames, more is not better! Just enough to achieve your desired frame rate and no more!

Source: Scawen
So, can we do something in setting to get LFS as smooth as AC?
Quote from bishtop :ah so its not to do with connection to the server or anything, there is a button which brings up some info that shows physics ect update which should give some insight, il have to take a look now then il post the key to press to show it Smile

EDIT - Go to settings and then misc then on the right hand side at the top click the + sign and it should show sleep phys wait . how do they look when you go to drive or turn ect.

In vr my phys is all way to left so a small fairly steady line with random small spikes . More than 3/4 of phys window clear. The wait line fills up half that window with Same small spikes . But always stays around half . In non vr the game doesn’t stutter at all and the wait is the same small line as phys with more than 3/4 of window clear . In vr , stutter or not those two lines remain the same . I have to wonder if it’s a setting since others it works ok . I tried both oculus and open vr same results .
if your VR headset is not 100hz you are going to see a mismatch of physics/fps, thats why the "stuters" or whatever one calls it.
im on a index and the best is to use 144hz, but hard to maintain the proper fps.
LFS needs a revamp to properly work in VR because of the hz.
At the moment its impossible to run it like assetto corsa. And everyone that doesnt feel the "stutters" is just not paying proper attention. Look to the sides when driving, its better to see it that way.
Did this ever get resolved?
Work in progress:

"The current public version of LFS runs the physics at 100 steps per second. When displayed at 60 frames per second (typical on a monitor) or at 90 fps (typical on a VR headset) the number of physics steps per graphical frame is not constant. Some graphical frames show a single physics step while others show two physics steps. For example at 60 fps there is a 2,2,1 pattern of physics steps per graphical frame. This mismatch produces a visible stutter that is particularly noticeable when objects are moving sideways across the screen. For example when looking to the side or when turning a tight corner at lower speeds. The stutter effect is especially noticeable in VR. We are experimenting with a new physics update rate of 1000Hz. The number of physics steps is a lot closer between subsequent graphical frames, so things look smoother. For example at 60 fps there is a 17,17,16 pattern of physics steps per graphical frame.

The 1000Hz physics update also allows lap times to be recorded to an accuracy of 1/1000 of a second and slow motion replays can appear smooth too. This change is also a possible route to a multithreaded version of LFS in which the graphics and physics code run on separate CPU cores, simultaneously, instead of having to share a single core. The physics could theoretically run in real time at steps of 0.001s, while the graphics code does all its tasks that have become a lot more complicated in the new graphics system, most notably because of the shadow maps that were required for real time lighting. We are currently in an early stage of some restructuring to allow the physics and graphics to run on separate threads. It's certainly experimental at this point but multithreading has important advantages and should be explored and evaluated. The best outcome would be constant physics rate as described above and a graphical frame rate that remains at the refresh rate of the display device."

https://www.lfs.net/20th-anniversary
Quote from Lucas McFly :Work in progress:

"The current public version of LFS runs the physics at 100 steps per second. When displayed at 60 frames per second (typical on a monitor) or at 90 fps (typical on a VR headset) the number of physics steps per graphical frame is not constant. Some graphical frames show a single physics step while others show two physics steps. For example at 60 fps there is a 2,2,1 pattern of physics steps per graphical frame. This mismatch produces a visible stutter that is particularly noticeable when objects are moving sideways across the screen. For example when looking to the side or when turning a tight corner at lower speeds. The stutter effect is especially noticeable in VR. We are experimenting with a new physics update rate of 1000Hz. The number of physics steps is a lot closer between subsequent graphical frames, so things look smoother. For example at 60 fps there is a 17,17,16 pattern of physics steps per graphical frame.

The 1000Hz physics update also allows lap times to be recorded to an accuracy of 1/1000 of a second and slow motion replays can appear smooth too. This change is also a possible route to a multithreaded version of LFS in which the graphics and physics code run on separate CPU cores, simultaneously, instead of having to share a single core. The physics could theoretically run in real time at steps of 0.001s, while the graphics code does all its tasks that have become a lot more complicated in the new graphics system, most notably because of the shadow maps that were required for real time lighting. We are currently in an early stage of some restructuring to allow the physics and graphics to run on separate threads. It's certainly experimental at this point but multithreading has important advantages and should be explored and evaluated. The best outcome would be constant physics rate as described above and a graphical frame rate that remains at the refresh rate of the display device."

https://www.lfs.net/20th-anniversary

Do you know when that statement was made? I'd love to be part of any beta testing for this new build.
Quote from jammy1 :Do you know when that statement was made? I'd love to be part of any beta testing for this new build.

18th August, 2022. If there is any test patch released, I'm sure you will get to know about it Smile
I'm still interested if there is a beta for this to test!

Any news?
There is no beta and it probably will not be. When it's ready Scawen will release the new LFS version and it's getting quite close, we're almost there Smile
Genuinely excited!
Me too but just to be clear it will still be a while, not this year!
That's fine Scawen, take your time.

Severe Lack of Smoothness in VR
(61 posts, started )
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