如何获取3D模型的大小?从 USDZ 文件/场景?

Question

我想从 USDZ 文件/Swift 中的场景中获取 3D 模型的大小。我该怎么做？目前我有一个用 swift 导入的 USDZ 文件，然后用代码转换为场景：

class ViewController: UIViewController, ARSCNViewDelegate {

@IBOutlet var sceneView: ARSCNView!

override func viewDidLoad() {
super.viewDidLoad()
sceneView.delegate = self
}

override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)

let configuration = ARImageTrackingConfiguration()

guard let trackedImages = ARReferenceImage.referenceImages(inGroupNamed: "Photos", bundle: Bundle.main) else {
print("No images available")
return
}

configuration.trackingImages = trackedImages
configuration.maximumNumberOfTrackedImages = 7

sceneView.session.run(configuration)
}

\MARK-: WHERE I CONVERT THE USDZ FILE INTO A SCENE TO DISPLAY
func renderer(_ renderer: SCNSceneRenderer, nodeFor anchor: ARAnchor) -> SCNNode? {

let node = SCNNode()

if let imageAnchor = anchor as? ARImageAnchor {
let plane = SCNPlane(width: imageAnchor.referenceImage.physicalSize.width, height: imageAnchor.referenceImage.physicalSize.height)
plane.firstMaterial?.diffuse.contents = UIColor(white: 1, alpha: 0.8)
let planeNode = SCNNode(geometry: plane)
planeNode.eulerAngles.x = -.pi / 2
guard let url = Bundle.main.url(forResource: "shipScene", withExtension: "usdz") else { fatalError() }
let mdlAsset = MDLAsset(url: url)
let shipScene = SCNScene(mdlAsset: mdlAsset)
let shipNode = shipScene.rootNode.childNodes.first!
shipNode.position = SCNVector3Zero
shipNode.position.z = 0.15

planeNode.addChildNode(shipNode)
node.addChildNode(planeNode)
}

return node
}

}

是要使用的正确代码

shipNode.boundingBox.max

但是我有点困惑如何使用边界框，因为有一个最大值/最小值？我使用哪一个？或者我什至如何使用它？

Answer 1

来自文档

例如，如果几何图形的边界框具有最小拐角{-1, 0, 2}和最大拐角{3, 4, 5}，则几何体顶点数据中的所有点的 x 坐标值介于-1.0和3.0之间(包括 和 (。

等等

let width = boundingBox.max.x - boundingBox.min.x
let height = boundingBox.max.y - boundingBox.min.y
let depth = boundingBox.max.z - boundingBox.min.z

Answer 2

找到了解决方案：

// For width:
shipNode.boundingBox.max.x
// For height:
shipNode.boundingBox.max.y