Unity XR

Stack overview

                  XR Interaction Toolkit (input + interaction)
                                  ↑
                          XR Plug-in Management
                          ↙           ↘
                    OpenXR        ARKit / ARCore
                       ↘             ↙
                   Native runtimes (Quest, Vision OS, Pico, mobile)

For VR (Quest, PCVR, Vision OS) → XRI 3.x + OpenXR plug-in. For AR (mobile) → AR Foundation + ARKit/ARCore providers. Mixed Reality on Quest 3 → AR Foundation features (passthrough, anchors) work on top of OpenXR.

XRI 3.x — interactors and interactables

// On a controller GameObject
NearFarInteractor   — combines direct grab + ray
TeleportInteractor  — for teleport locomotion

// On an interactable object
XRGrabInteractable
XRSocketInteractor (slot)
XRSimpleInteractable (just hover/select)

Use the Interaction Manager in the scene; both interactors and interactables register with it.

Locomotion

XRI provides:

• Continuous Move + Continuous Turn — comfort options (snap turn, vignette).
• Teleport — TeleportationProvider + TeleportationArea/Anchor.
• Climb — ClimbProvider + ClimbInteractable.

Always offer multiple comfort options (snap turn 30°/45°, smooth turn, vignette intensity slider).

AR Foundation basics

public class PlaneSpawner : MonoBehaviour {
    [SerializeField] private ARRaycastManager raycastManager;
    [SerializeField] private GameObject prefab;
    private static readonly List<ARRaycastHit> Hits = new();

    void Update() {
        if (!Touchscreen.current?.primaryTouch.press.wasPressedThisFrame ?? true) return;
        var pos = Touchscreen.current.primaryTouch.position.ReadValue();
        if (raycastManager.Raycast(pos, Hits, TrackableType.PlaneWithinPolygon)) {
            var hit = Hits[0].pose;
            Instantiate(prefab, hit.position, hit.rotation);
        }
    }
}

Add ARSession, ARSessionOrigin (or XROrigin in newer AR Foundation), and the relevant manager components (ARPlaneManager, ARAnchorManager, ARFaceManager, etc.) to the scene.

Hand tracking

Use Unity's XR Hands package (com.unity.xr.hands) for cross-platform hand poses (joints, gestures).

Performance for XR

• Target frame rate: Quest 2 = 72/90Hz, Quest 3 = 90/120Hz, Vision OS = 90Hz. Missing frame budget causes nausea — non-negotiable.
• Single-Pass Instanced stereo rendering (URP): cuts vertex shader work in half.
• Foveated rendering on supported platforms (Quest 3 via OpenXR extension).
• Reproject / spacewarp as a fallback — but design for native frame rate first.

Anti-patterns

Production checklist

• Frame rate met on minimum-spec headset
• Comfort options menu (turn type, vignette, height calibration)
• Hand tracking + controllers both supported (where platform allows)
• AR session error states handled (camera permission denied, plane lost)
• Single-pass stereo enabled in URP
• No motion sickness on a fresh tester