我想移动摄像头的位置，让物体看起来更小，但是如果我设置了更大的z值，物体就会消失。例如：cameraNode.position = SCNVector 3（0，0，800），然后硬币就会消失。我是SceneKit新手，希望得到一些帮助，谢谢！或者你能介绍一个基于SwiftUI的SceneKit教程吗？

import Foundation
import SceneKit

class CoinFlipGameScene: SCNScene{
    
    override init() {
        super.init()
        
        createCoinNode()
        setUpCamera()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

extension CoinFlipGameScene{
    
    func createCoinNode(){
        let coinGeometry = SCNBox(width: 100, height: 100, length: 0, chamferRadius: 0)
        
        let coinHeadMaterial = SCNMaterial()
        coinHeadMaterial.diffuse.contents = UIImage(named: "coin-head")
        
        let coinTailMaterial = SCNMaterial()
        coinTailMaterial.diffuse.contents = UIImage(named: "coin-tail")

        coinGeometry.materials = [coinHeadMaterial, coinHeadMaterial, coinTailMaterial]
        
        let coinNode = SCNNode(geometry: coinGeometry)
        coinNode.position = SCNVector3(x: 0, y: 0, z: 0)
        self.rootNode.addChildNode(coinNode)
    }
    
    func setUpCamera(){
        let cameraNode = SCNNode()
        cameraNode.camera = SCNCamera()
        cameraNode.position = SCNVector3(0, 0, 100)

        self.rootNode.addChildNode(cameraNode)
        
    }
}

import SwiftUI
import SceneKit

struct CoinFlipView: View {
    
    var scene: SCNScene{
        let scene = CoinFlipGameScene()
        
        return scene
    }
    
    var body: some View {
        SceneView(scene: scene, options: [.allowsCameraControl])
            .background(.clear)
    }
}

struct CoinFlipView_Previews: PreviewProvider {
    static var previews: some View {
        CoinFlipView()
    }
}

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