代码之家 › 专栏 › 技术社区 › Andy Jazz

无法将三维模型作为SCN度量输入MDLMesh容器

modelio ios12 arkit scenekit swift

3

Andy Jazz · 技术社区 · 6 年前

我想装货 USDZ 将三维对象转换为空的 SceneKit的场景,然后将其处理为 MDL 网格。

这是我的密码:

import ARKit
import SceneKit.ModelIO

let scene = SCNScene(named: "art.scnassets/emptyScene.scn")!

if let filePath = Bundle.main.path(forResource: "Helicopter", 
                                        ofType: "usdz", 
                                   inDirectory: "art.scnassets") {

    let refURL = URL(fileURLWithPath: filePath)
    let refNode = SCNReferenceNode(url: refURL)
    refNode?.load()
    scene.rootNode.addChildNode(refNode!)
}

let helicopterGeo = refNode!.geometry

let mdlMesh = MDLMesh(scnGeometry: helicopterGeo!)      // ERROR APPEARS HERE
try! mdlMesh.makeVerticesUniqueAndReturnError()
let flattenedGeometry = SCNGeometry(mdlMesh: mdlMesh)
let flattenedNode = SCNNode(geometry: flattenedGeometry)
scene.rootNode.addChildNode(flattenedNode)

"Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value"

问题是 :我应该使用什么方法来分配 "Helicopter.usdz" helicopterGeo 常数?

请帮我找个解决办法!

你可以下载 美元 HERE .

3 回复 | 直到 5 年前

1

Brandon 6 年前

这应该起作用:

var scene: SCNScene!
if let filePath = Bundle.main.path(forResource: "Helicopter", 
                                    ofType: "usdz", 
                               inDirectory: "art.scnassets") {

    let refURL = URL(fileURLWithPath: filePath)
    let mdlAsset = MDLAsset(url: refURL)
    scene = SCNScene(mdlAsset: mdlAsset)

}

SCNReferenceNode 仅适用于.scn文件。然后可以从的子节点获取几何体 rootNode scene .

let helicopterNode = scene.rootNode.childNode(withName: "helicopter", recursively: true)
let geometry = helicopterNode.geometry!

AR Quick Look Gallery

var scene: SCNScene!
if let filePath = Bundle.main.path(forResource: "retrotv",
                                   ofType: "usdz",
                                   inDirectory: "art.scnassets") {

    let refURL = URL(fileURLWithPath: filePath)
    let mdlAsset = MDLAsset(url: refURL)
    scene = SCNScene(mdlAsset: mdlAsset)

    let tvNode = scene.rootNode.childNode(withName: "RetroTVBody", recursively: true)
    let geometry = tvNode!.geometry!

} else {

    print("invalid path!")

}

上面的代码也适用于 tvNode 和 geometry 境外申报 if let 声明。

2

1

EmilioPelaez 6 年前

refNode .

加载后放置一个断点,并使用调试器查看它是否有任何子级。那些孩子有几何学吗?他们有学几何的孩子吗?

创建三维资源时,有时会在父节点上对多个节进行分组,在许多情况下,父节点为空。

3

1

Andy Jazz 6 年前

usdz Scene graph pHelicopter1 它刚刚显现出来 Helicopter pCube1 Extrude 工具。

以下是最终代码,它运行良好:

import ARKit
import SceneKit.ModelIO

//..........................................................

var scene = SCNScene(named: "art.scnassets/EmptyScene.scn")!

if let filePath = Bundle.main.path(forResource: "Helicopter",
                                        ofType: "usdz",
                                   inDirectory: "art.scnassets") {

    let refURL = URL(fileURLWithPath: filePath)
    let mdlAsset = MDLAsset(url: refURL)
    scene = SCNScene(mdlAsset: mdlAsset)
    let helicopterNode = scene.rootNode.childNode(withName: "pHelicopter1", 
                                               recursively: true)

    let geometry = helicopterNode!.geometry!
    let mdlMesh = MDLMesh(scnGeometry: geometry)
    try! mdlMesh.makeVerticesUniqueAndReturnError()
    let flattenedGeometry = SCNGeometry(mdlMesh: mdlMesh)
    let flattenedNode = SCNNode(geometry: flattenedGeometry)
    scene.rootNode.addChildNode(flattenedNode)

} else {
    print("Invalid path!")
}