USDZ模型的SceneKit变换颜色

Question

我使用USDZ文件创建了一个带有SceneKit的视图，如何在SwiftUI代码中将特定材料的颜色从灰色直接更改为其他颜色？

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var scene = SCNScene(named: "2020_BMW_M5.usdz")
var body: some View {       
    VStack {
        SceneView(scene: scene, 
                options: [.autoenablesDefaultLighting, .allowsCameraControl])
    }
}

Answer 1

使用下标方法(.childNodes[n].childNodes[n].childNodes[n])在所需的层次结构中建模，然后按照通常的方式更改其颜色：

import SwiftUI
import SceneKit

struct ContentView : View {
    var body: some View {
        return SceneKitViewContainer().ignoresSafeArea()
    }
}

struct SceneKitViewContainer: UIViewRepresentable {
    
    func makeUIView(context: Context) -> SCNView {
        let scnView = SCNView(frame: .zero)
        scnView.allowsCameraControl = true
        scnView.autoenablesDefaultLighting = true
        scnView.scene = SCNScene(named: "Model.usdz")
        
        let model = scnView.scene?.rootNode.childNode(withName: "SomeModel", 
                                                   recursively: true)
        model?.childNodes[1].geometry?.firstMaterial?.diffuse.contents = 
                                                                UIColor.red
        print(model?.childNodes[1])

        return scnView
    }
    func updateUIView(_ uiView: SCNView, context: Context) { }
}