Jittery world around stationary character


I am creating an infinite runner. I have an object in my scene that is permanently moving to the left (“Scroller”). Whenever I create obstacles, I parent them to the “Scroller”. Once they move off screen, I set them to inactive.

The player object does not move at all, nor does the camera. Both of these objects are 100% stationary, as the Scroller object is doing all of the movement.


The movement of the one parent object is jerky in the editor (thus causing the children objects to jitter), and there is very jerky movement in non-development WebGL, PC and Android build.

More Details and Reiteration:

  • Each obstacle has a rigidbody attached.
  • The jitter occurs randomly, sometimes few seconds, sometimes every frame.
  • There are no more than 20 obstacles active at any point in time.
  • Only the “Scroller” object is moving, and every other object is being parented to it
  • I am instantiating one of many Obstacle collections, and then parenting that collection to the “Scroller.”

To reiterate that last point, my hierarchy looks like - Scroller → Obstacles Parent - > Obstacle, Obstacle, Obstacle


My movement script:

    private void Update()
        scroller.position = Vector3.Lerp(scroller.position, scroller.position + new Vector3(-1, 0, 0), Time.deltaTime * speed);
        //scroller.position += new Vector3(-1, 0, 0) * (Time.smoothDeltaTime * speed);

Using LateUpdate provides roughly the same experience, give or take a few hairs from my head.

@Shingox It’s not clear as to whether you’re talking about is “jittery” framerate or jittery movement with the physics and whatnot.

If it’s framerate, a stutter every now and then could be related to garbage collection. If you’re constantly creating new object and not getting rid of the old objects I imagine you’ll just run out of memory at some point. Re-using the deactivated objects is what you want to do, ideally.

If it’s some issue with the physics, I can imagine physics would be wonky if you’re scrolling the entire environment that everything is standing on. Instead of scrolling the ground, just keep a physics object for the ground as a static object and move everything else around it. Just an idea, anyway. Try different types of hierarchies until you find something that works for you.