Fast moving synced objects stutter when close to the player
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Z0NE
I have a racing world where AI cars are navmesh agents for the person starting a race, and synced objects for other players. There are no scripts running on them for other players, it is just their position that is being synced. When they are close to other players, they will appear to stutter back and forth. The more players in the world, the more they will stutter. When in the distance, they do not stutter at all.
This is a new problem, it was not happening in prior builds of VRC.
See attached movie (sorry for the dual audio, I have 2 clients open to test)
*UPDATE
This appears to be tied to framerate. If I lock my FPS to 60, I do not see the problem, but if I uncap it and hit FPS much higher (120+ etc), the stuttering occurs. It appears that the objects being synced are only reporting their position at 60fps with no interpolation to account for users running at higher framerates. It is probably not noticeable when things move at slower speeds, but in instances like my racing world, the difference between 60 and 120+ will be obviously cause a stutter when objects have a velocity close to 100 and you also do while moving right next to them!
*UPDATE 2
This only happens if I use my monitor with a 60Hz refresh rate, then uncap the the framerate. If I use my Valve Index at 120 or 144Hz with an uncapped framerate, I will not get any stuttering on objects that I do not own that are moving using ObjectSync as my FPS will rarely get higher than the refresh rate of my headset. So ObjectSync is tied to the Hz that your display is when the game launches, or probably FixedUpdate in some way? This is why I see stuttering when running my world FPS uncapped on my display at 60Hz.
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StormRel
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StormRel
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Hi! Thanks for reporting this. Can you provide the world ID so we can repro?
Z0NE
Sure, this is the in-development one which also includes Android / iOS support: wrld_a665ef4e-75fe-478f-8786-1a1364637f39
Z0NE
StormRel You'll need to start a multiplayer race and verify it on the instances that join the race. The person starting the race will not see the issue as they are controlling the AI cars.
Z0NE
StormRel Ok, so I have pinned this down further! It is tied to framerate. If I lock my FPS to 60, it is fine with no stuttering, but if I uncap the FPS, they stutter. So most likely their position is updating at 60fps or some value lower than my max fps which makes it look like they are stuttering. And this is why is it really only noticeable at high speeds. I hope this helps!
Z0NE
StormRel I checked on my Index which runs at 120Hz and didn't see any stuttering as a player viewing & not owning synced objects. The display I was using before was 60Hz so it seems that objects sync & update at the Hz of your display (possibly like FixedUpdate) and if your FPS goes over that while uncapped, you will see stuttering