I have written this function: @available(macOS 26.0, *) func instancing() async -> Entity { let entity = Entity() do { // 1. Create a CustomMaterial let library = offscreenRenderer.pointRenderer!.device.makeDefaultLibrary()! let surfaceShader = CustomMaterial.SurfaceShader( named: "surfaceShaderWithCustomUniforms", // This must match the function name in Metal in: library ) let instanceCount = 10 // No idea how to actually use this... // let bufferSize = instanceCount * MemoryLayout<UInt32>.stride // // // Create the descriptor // var descriptor = LowLevelBuffer.Descriptor(capacity: bufferSize, sizeMultiple: MemoryLayout<UInt32>.stride) // // // Initialize the buffer // let lowLevelBuffer = try LowLevelBuffer(descriptor: descriptor) // lowLevelBuffer.withUnsafeMutableBytes { rawBytes in // // Bind the raw memory to the UInt32 type // let pointer = rawBytes.bindMemory(to: UInt32.self) // pointer[1] = 0xff_0000 // pointer[0] = 0x00_ff00 // pointer[2] = 0x00_00ff // pointer[3] = 0xff_ff00 // pointer[4] = 0xff_00ff // pointer[5] = 0x00_ffff // pointer[6] = 0xff_ffff // pointer[7] = 0x7f_0000 // pointer[8] = 0x00_7f00 // pointer[9] = 0x00_007f // } var material = try CustomMaterial(surfaceShader: surfaceShader, lightingModel: .lit) material.withMutableUniforms(ofType: SurfaceCustomUniforms.self, stage: .surfaceShader) { params, resources in params.argb = 0xff_0000 } // 2. Create the ModelComponent (provides the MESH and MATERIAL) let mesh = MeshResource.generateSphere(radius: 0.5) let modelComponent = ModelComponent(mesh: mesh, materials: [material]) // 3. Create the MeshInstancesComponent (provides the INSTANCE TRANSFORMS) let instanceData = try LowLevelInstanceData(instanceCount: instanceCount) instanceData.withMutableTransforms { transforms in for i in 0..<instanceCount { let instanceAngle = 2 * .pi * Float(i) / Float(instanceCount) let radialTranslation: SIMD3<Float> = [-sin(instanceAngle), cos(instanceAngle), 0] * 4 // Position each sphere around a circle. let transform = Transform( scale: .one, rotation: simd_quatf(angle: instanceAngle, axis: [0, 0, 1]), translation: radialTranslation ) transforms[i] = transform.matrix } } let instancesComponent = try MeshInstancesComponent(mesh: mesh, instances: instanceData) // 4. Attach BOTH to the same entity entity.components.set(modelComponent) entity.components.set(instancesComponent) } catch { print("Failed to create mesh instances: \(error)") } return entity } and this is the corresponding Metal shader typedef struct { uint32_t argb; } SurfaceCustomUniforms; [[stitchable]] void surfaceShaderWithCustomUniforms(realitykit::surface_parameters params, constant SurfaceCustomUniforms &customParams) { half3 color = { static_cast<half>((customParams.argb >> 16) & 0xff), static_cast<half>((customParams.argb >> 8) & 0xff), static_cast<half>(customParams.argb & 0xff) }; params.surface().set_base_color(color); } which works well and generates 10 red spheres. While listening to the WWDC25 presentation on what's new in RealityKit I am positive to hear the presenter saying that it is possible to customise each instance using a LowLevelBuffer, but so far all my attempts have failed. Is it possible, and if so how ? Thanks for reading and for your help. Kind regards, Christian