## ARKit Implementation ```swift import ARKit import RealityKit class SpatialMappingViewController: UIViewController, ARSessionDelegate { @IBOutlet var arView: ARView! override func viewDidLoad() { super.viewDidLoad() // Configure AR session for spatial mapping let configuration = ARWorldTrackingConfiguration() configuration.sceneReconstruction = .mesh configuration.planeDetection = [.horizontal, .vertical] arView.session.delegate = self arView.session.run(configuration) } func session(_ session: ARSession, didUpdate anchors: [ARAnchor]) { for anchor in anchors { if let meshAnchor = anchor as? ARMeshAnchor { updateMeshGeometry(meshAnchor) } } } func updateMeshGeometry(_ anchor: ARMeshAnchor) { let meshGeometry = anchor.geometry // Convert to ModelEntity var descriptor = MeshDescriptor() descriptor.positions = MeshBuffers.Positions( meshGeometry.vertices ) descriptor.faces = MeshDescriptor.Primitives( .triangles(meshGeometry.faces) ) let mesh = try! Mesh.generate(from: [descriptor]) let material = SimpleMaterial( color: .gray.withAlphaComponent(0.3), roughness: 0.5 ) let model = ModelEntity(mesh: mesh, materials: [material]) model.transform = Transform(matrix: anchor.transform) arView.scene.addAnchor(model) } } ``` ### Persistent Anchors ```swift func saveWorldMap() { arView.session.getCurrentWorldMap { worldMap, error in guard let map = worldMap else { print("Error: \(error!.localizedDescription)") return } // Serialize and save do { let data = try NSKeyedArchiver.archivedData( withRootObject: map, requiringSecureCoding: true ) UserDefaults.standard.set(data, forKey: "worldMap") } catch { print("Can't save map") } } } func loadWorldMap() { guard let data = UserDefaults.standard.data(forKey: "worldMap"), let worldMap = try? NSKeyedUnarchiver.unarchivedObject( ofClass: ARWorldMap.self, from: data ) else { return } let configuration = ARWorldTrackingConfiguration() configuration.initialWorldMap = worldMap arView.session.run(configuration) } ``` ## ARCore Implementation ```kotlin class SpatialMappingActivity : AppCompatActivity() { private lateinit var arFragment: ArFragment private val sceneNodes = mutableMapOf<Anchor, TransformableNode>() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) arFragment = supportFragmentManager .findFragmentById(R.id.arFragment) as ArFragment arFragment.setOnTapArPlaneListener { hitResult, _, _ -> placeObject(hitResult) } setupPlaneDetection() } private fun placeObject(hitResult: HitResult) { val anchor = hitResult.createAnchor() val anchorNode = AnchorNode(anchor).apply { setParent(arFragment.arSceneView.scene) } // Load 3D model ModelRenderable.builder() .setSource(this, Uri.parse("model.glb")) .build() .thenAccept { model -> val node = TransformableNode(arFragment.transformationSystem) node.renderable = model node.setParent(anchorNode) node.select() sceneNodes[anchor] = node } } } ``` ## Occlusion and Physics ``` SPATIAL FEATURES: ├── Mesh reconstruction ├── Plane detection ├── Image tracking ├── Object detection └── Scene understanding OPTIMIZATION: ├── Level of Detail (LOD) ├── Frustum culling ├── Occlusion culling └── Shadow optimization ```