/hz-unity-meta-mixed-reality-utility-kit

name: hz-unity-meta-mixed-reality-utility-kit
license: Apache-2.0
description: Meta XR Mixed Reality Utility Kit (MRUK) (com.meta.xr.mrutilitykit) for Unity XR development. Use when working with Scene API data (rooms, walls, floors, furniture), spawning prefabs on scene anchors, placing virtual objects in the real world, world locking to prevent anchor drift, raycasting against room geometry, generating NavMesh from scene data, environment depth raycasting for instant placement without scanning, Passthrough Camera Access (PCA), trackable detection (keyboards, QR codes), destructible scene meshes, space maps, room sharing for multiplayer, or any MR scene-aware feature.

Meta XR Mixed Reality Utility Kit (MR Utility Kit, MRUK, com.meta.xr.mrutilitykit)

The Meta XR Mixed Reality Utility Kit (MR Utility Kit, MRUK) is a Unity package that provides high-level tools on top of the Scene API for building scene-aware Mixed Reality (MR) experiences. It is designed to be used in conjunction with the Meta XR Core SDK. It handles scene data loading and querying, spawning prefabs on real-world surfaces, world locking to prevent anchor drift, environment raycasting for instant placement without scanning, passthrough camera access, NavMesh generation from room geometry, and trackable detection (keyboards, QR codes).

Package: com.meta.xr.mrutilitykit

Finding the SDK Source

The package `com.meta.xr.mrutilitykit` may be located in different places depending on the project setup:

• `Library/PackageCache/com.meta.xr.mrutilitykit@<hash>/` (cached from registry)
• `Packages/com.meta.xr.mrutilitykit/` (local package reference)
• A custom on-disk path (embedded or local folder)

**Before searching for SDK source, first locate the package root** by searching for a known file by filename pattern:

**/com.meta.xr.mrutilitykit*/Core/Scripts/MRUK.cs

Then use the resolved parent path for all subsequent search operations.

Quick Reference

| Task | Class / Component | Source File | Key Entry Point | |---|---|---|---| | Load scene from device | `MRUK` | `Scripts/MRUK.cs` | `LoadSceneFromDevice()` | | Load scene from prefab/JSON | `MRUK` | `Scripts/MRUK.cs` | `LoadSceneFromPrefab()`, `LoadSceneFromJsonString()` | | Get current room | `MRUK` | `Scripts/MRUK.cs` | `GetCurrentRoom()` | | Prevent anchor drift | `MRUK` | `Scripts/MRUK.cs` | `EnableWorldLock = true` | | Query room geometry | `MRUKRoom` | `Scripts/MRUKRoom.cs` | `Raycast()`, `IsPositionInRoom()` | | Find surfaces / closest point | `MRUKRoom` | `Scripts/MRUKRoom.cs` | `TryGetClosestSurfacePosition()`, `GenerateRandomPositionOnSurface()` | | Get anchor properties | `MRUKAnchor` | `Scripts/MRUKAnchor.cs` | `Label`, `PlaneRect`, `VolumeBounds` | | Spawn prefabs on anchors | `AnchorPrefabSpawner` | `Scripts/AnchorPrefabSpawner.cs` | `PrefabsToSpawn`, `SpawnOnStart` | | Find random spawn positions | `FindSpawnPositions` | `Scripts/FindSpawnPositions.cs` | `StartSpawn()`, `SpawnLocations` | | 27-slice mesh resizing | `GridSliceResizer` | `Scripts/GridSliceResizer.cs` | `ResizeTo(Vector3)` | | Generate visual meshes | `EffectMesh` | `Scripts/EffectMesh.cs` | `CreateMesh()`, `CutHoles` | | Breakable scene geometry | `DestructibleGlobalMeshSpawner` | `Scripts/DestructibleGlobalMeshSpawner.cs` | `CreateOnRoomLoaded` | | GPU distance field texture | `SpaceMapGPU` | `Scripts/SpaceMapGPU.cs` | `GetSpaceMap()`, `StartSpaceMap()` | | Boundary proximity fade | `RoomGuardian` | `Scripts/RoomGuardian.cs` | `GuardianDistance`, `GuardianMaterial` | | NavMesh from scene | `SceneNavigation` | `Scripts/SceneNavigation.cs` | `BuildSceneNavMesh()` | | Depth API raycasting | `EnvironmentRaycastManager` | `Scripts/EnvironmentRaycastManager.cs` | `Raycast()`, `PlaceBox()` | | Passthrough camera images | `PassthroughCameraAccess` | `Scripts/PassthroughCameraAccess.cs` | `GetTexture()`, `GetCameraPose()` | | Track keyboards / QR codes | `MRUKTrackable` | `Scripts/MRUKTrackable.cs` | `TrackableType`, `MarkerPayloadString` | | Instant placement (no scan) | `PointAndLocate` | `Scripts/BuildingBlocks/InstantContentPlacement/` | `TryLocateSpace()` | | Share rooms (multiplayer) | `MRUK` | `Scripts/MRUK.cs` | `ShareRoomsAsync()`, `LoadSceneFromSharedRooms()` |

All source file paths are relative to the package root (see "Finding the SDK Source" above).

Architecture

Object Hierarchy

MRUK (singleton MonoBehaviour)
 └── MRUKRoom (child GameObjects, one per room)
      └── MRUKAnchor (children of rooms: walls, floors, furniture, etc.)

• **`MRUK.Instance`** is the central hub. It loads scene data, manages rooms, handles world locking, and provides the `SceneSettings` configuration.
• **`MRUKRoom`** represents a physical room. Provides spatial queries (raycasting, position checks, surface queries) and holds `Anchors`, `WallAnchors`, `FloorAnchors`, `CeilingAnchors`, `GlobalMeshAnchor`.
• **`MRUKAnchor`** represents a single scene element (wall, table, couch, etc.). Has a `Label` (SceneLabels flags), optional `PlaneRect` (2D bounds), `VolumeBounds` (3D bounds), and `PlaneBoundary2D` (polygon points).
• **`MRUKTrackable`** extends `MRUKAnchor` for runtime-detected objects (keyboards, QR codes).

Native Library

A C/C++ shared library handles world locking, anchor discovery, and coordinate conversion (OpenXR right-handed ↔ Unity left-handed). A hidden `MRUKGlobalContext` MonoBehaviour (DontDestroyOnLoad) ticks the native context every frame. You never call these directly.

Component Pattern

All feature components (AnchorPrefabSpawner, EffectMesh, FindSpawnPositions, SceneNavigation, SpaceMapGPU, RoomGuardian, DestructibleGlobalMeshSpawner) follow the same pattern: 1. A `SpawnOnStart` / `CreateOnStart` / `BuildOnSceneLoaded` property of type `MRUK.RoomFilter` controls automatic initialization 2. In `Start()`, they call `MRUK.Instance.RegisterSceneLoadedCallback(...)` which fires immediately if the scene is already loaded 3. They also expose manual methods