XRGrabInteractable (VelocityTracking): Massive lag/stutter when moving player

[MentalGames]

Hey partypeople,

I’m using Unity 2020.1.6f1, the Oculus plugin and the XR Toolkit and really the only thing that absolutely is a no go for my game is the extreme lag/stutter I experience when moving the player. Can’t have a handgun going haywire in a shooter game, now can we?

I wasn’t able to find out if this is a specific problem I’m facing (f.e. because I use the “wrong” version of Unity) or if this is a XR Toolkit problem. Grabbing and playing around with objects is smooth and how I would like it, but as soon as I’m walking, the grabbed object is lagging extremely.

Any ideas or suggestions would be highly appreciated!

[bobby2dazzler]

Me too. And same when throwing objects. Would love sime help

[CassieNova]

I was just going to post a question about this. Instantaneous is smooth as butter, but velocity tracking is all over the place. I tried the same settings provided in the sample projects provided by Unity and everything is a bit smoother if I stand still, BUT as soon as I start moving, the interactable is a jittery mess.

Maybe I’m asking for too much, but it would be so nice to get that Half Life Alyx level of physics.

[TheMaximL]

The reason this happens is because velocity tracking using the physics engine to move the object (via velocity) but the normal movement systems move the player via transfoms. A simple way to allievate this is to make the object a child of the XR rig when selected. A more complex, but proper solution is to create a physics based locomotion system.

If you want high-quality, VR physics you’ll have to roll your own locomotion and grabbing systems. It’s a rabbit-hole but worth going down. Be prepared for a lot of quaterion and vector math though.

[Geouug]

I just tried @TheMaximL 's suggestion and it worked beautifully. I created a new class specifically for object’s I want to be velocity tracked, and replaced the XRGrabInteractable component on those GameObjects.

Here’s my implementation:

using UnityEngine.XR.Interaction.Toolkit;

public class XRGrabVelocityTracked : XRGrabInteractable
{
    protected override void OnSelectEntered(XRBaseInteractor interactor)
    {
        SetParentToXRRig();
        base.OnSelectEntered(interactor);
    }

    protected override void OnSelectExited(XRBaseInteractor interactor)
    {
        SetParentToWorld();
        base.OnSelectExited(interactor);
    }

    public void SetParentToXRRig()
    {
        transform.SetParent(selectingInteractor.transform);
    }

    public void SetParentToWorld()
    {
        transform.SetParent(null);
    }
}

[SmithySFC]

@Geouug

I just tried @TheMaximL 's suggestion and it worked beautifully. I created a new class specifically for object’s I want to be velocity tracked, and replaced the XRGrabInteractable component on those GameObjects.

Here’s my implementation:

using UnityEngine.XR.Interaction.Toolkit;

public class XRGrabVelocityTracked : XRGrabInteractable
{
    protected override void OnSelectEntered(XRBaseInteractor interactor)
    {
        SetParentToXRRig();
        base.OnSelectEntered(interactor);
    }

    protected override void OnSelectExited(XRBaseInteractor interactor)
    {
        SetParentToWorld();
        base.OnSelectExited(interactor);
    }

    public void SetParentToXRRig()
    {
        transform.SetParent(selectingInteractor.transform);
    }

    public void SetParentToWorld()
    {
        transform.SetParent(null);
    }
}

THANKS SO MUCH FOR THIS!!!

[Bender_R]

@Geouug

I just tried @TheMaximL 's suggestion and it worked beautifully. I created a new class specifically for object’s I want to be velocity tracked, and replaced the XRGrabInteractable component on those GameObjects.

Here’s my implementation:

using UnityEngine.XR.Interaction.Toolkit;

public class XRGrabVelocityTracked : XRGrabInteractable
{
    protected override void OnSelectEntered(XRBaseInteractor interactor)
    {
        SetParentToXRRig();
        base.OnSelectEntered(interactor);
    }

    protected override void OnSelectExited(XRBaseInteractor interactor)
    {
        SetParentToWorld();
        base.OnSelectExited(interactor);
    }

    public void SetParentToXRRig()
    {
        transform.SetParent(selectingInteractor.transform);
    }

    public void SetParentToWorld()
    {
        transform.SetParent(null);
    }
}

Hi there,

Thanks a lot for sharing this. It sure fixes the stuttering issue! But unfortunately when I do this, it looks like the pivot point for my gun isn’t working anymore. I use the pivot point (empty gameobject) in the Attach Transform of the XR Grab Interactable. Any idea of how to fixe this?

Thanks a lot!!

Cheers

[BulletproofE]

@Bender_R

Hi there,

Thanks a lot for sharing this. It sure fixes the stuttering issue! But unfortunately when I do this, it looks like the pivot point for my gun isn’t working anymore. I use the pivot point (empty gameobject) in the Attach Transform of the XR Grab Interactable. Any idea of how to fixe this?

Thanks a lot!!

Cheers

Hey did you figure this out same thing for me?

[Bender_R]

@BulletproofE

Hey did you figure this out same thing for me?

Nope… Haven’t found fix for this…

[KineticBen]

Parenting the object to the XR rig itself, rather than the interactor object worked for me

[Widanon]

This didn’t seem to work for me at all with VelocityTracking. Only with Kinematic. Do you need to use any of the other smoothing settings to get VT to work?

[roman_prusakevich]

I disabled Position Tracking in XR Grabbable, instead I update position via script when “OnSelectEntered” event is called .

[Davidc4ke]

@roman_prusakevich

I disabled Position Tracking in XR Grabbable, instead I update position via script when “OnSelectEntered” event is called .

Hi Roman, could you send the full script you used for this? I am not sure I understand from the snippet alone.

[Christian_Perri]

@TheMaximL

Il motivo per cui ciò accade è perché il rilevamento della velocità utilizza il motore fisico per spostare l’oggetto (tramite la velocità), ma i normali sistemi di movimento muovono il giocatore tramite trasformazioni. Un modo semplice per alleviare questo è rendere l’oggetto un figlio del rig XR quando selezionato. Una soluzione più complessa, ma adeguata, è creare un sistema di locomozione basato sulla fisica.

Se vuoi una fisica VR di alta qualità, dovrai usare i tuoi sistemi di locomozione e di presa. È una tana del coniglio, ma vale la pena andarci. Preparati per un sacco di quaterion e matematica vettoriale.

i am trying to set the controller as a child of the XR origin,but i have still the problem

[Christian_Perri]

@KineticBen

Associare l’oggetto al rig XR stesso, piuttosto che l’oggetto interagente ha funzionato per me

How did you do?