jerking on client with Deltatime

Hello everyone,

I have a blade that swings back and forth and the function runs via a timeline.

If I start the game via NULL subsystem, the blade jerks with the client when I am ingame.

As soon as I tap out, it is smooth again.

Even if I look at the timeline values, you can see how the values are skipped as soon as I go back into the game.

I have replicated the curve and the timeline.

You can see the difference in the picture. Above the red line I am outside the game and below I am ingame.

Does anyone have a solution for the timeline?

But as soon as I limit the FPS to 60, the jerking on the client is gone. The problem has not yet occurred on the server side.

Is this in editor? (pie or selected viewport). Maybe the use less cpu in background flag is causing this


When you are the client window, the server (if it’s a listen server) may get less cpu cycles.

A bit of a shot in the dark but worth a try.

Do you use the command prompt to start the game or is the editor also used?

The problem also occurs in the editor, but only when I set the FPS to 200.

So to summarize:

  • Use of NULL subsystem
  • If it is opened in the editor, the problem is only if you set FPS fix to 200 FPS, so that the maximum performance of the PC can be used.
  • Of course, the problem also occurs when the game is opened via command prompt, unless I limit the FPS.

Could the reason be that the computer is overloaded because I start two games on one computer and because it is the tick function?

But even if this is the case. There should be a solution for that, right?

When I look at the FPS, it shows around 120 fps even when starting via the command prompt. Nevertheless, the DeltaTime fluctuates and the pendulum axe jerks.

Would the problem disappear if I started the client on a different computer?
But I would still wonder whether this is normal.

Try running both instances with smaller resolutions to see if it’s not a calculation hiccup where the pc struggles for a small time gathering resources.

So if I have the “server” (client1) in a small window and the client2 fullscreen, then the problem is not.

The same is also true if I make the “server” (client1) fullscreen and client2 small, the problem does not exist.
However, if both are fullscreen again, then this misbehavior is present again.

Then it’s most likely your pc just can’t handle two simultaneous sessions. Maybe your graphics card fill rate can be causing a bottleneck for the pc.

You could try packing the game and running it without the editor and see if you get the same jitters. Best scenario would be to test on 2 physical pc’s networked together on a packed version of the game.

That way the editor won’t eat up resources

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Now I already have an I7-11700KF and an RTX 3060TI and 31.9 GB RAM in it. xD
I only have 4 Actors in my Scene. xD

Then I’ll have to see if I can get a second PC or someone who can test with me regularly. Or I can test in a lower resolution or lower the FPS to 60, because then the problem won’t occur.

In a tutorial on Udemy, an interpolation was created for a car because it is jerky.
I thought I could solve the problem with that. :sweat_smile::neutral_face:

Do you think this would also solve the problem if I stick with it and try to solve it with interpolation?

You could animate the blade via the timeline on the server and just replicate over the swing axis angle (if it’s a pendulum type of motion) to the client and reconstruct the motion there with the replicated angle.

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I had this constelation at first and then changed it to Tick because the problem occurred.
Then I saw that the problem also occurs with Tick and then it occurred to me that the timeline also runs via Tick, if I’m not mistaken, right?

bladeMP.zip (58.9 KB)

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Thank you very much for your help. =)

Okay. I don’t know why, but the problem no longer occurs in the editor.

In the editor it doesn’t take full power from my PC anymore, only when I open the game via command prompt.

I’ll limit the FPS to 60 for now and see if I can use my old computer as a second device. ^^

But I will still create a pendulum with timeline as a test. =)

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