USDZ 实体与模型实体中可用的动画和碰撞行为

Question

我从 Sketchfab 购买了 2 个 USDZ 模型。但我不明白为什么行为不同。

第一个模型，我可以使用

ModelEntity

添加

object.model!.mesh.bounds.extents

并存储

object.availableAnimations[0]

struct ImmrsiveView: View {

    @State var object: ModelEntity? = nil
    @State var animation: AnimationResource? = nil

    var body: some View {
        RealityView { content in
            do {
                object = try await ModelEntity(named: "speaker")

                if let object {

                    let objectBound = object.model!.mesh.bounds.extents
                    object.components.set(CollisionComponent(shapes: [.generateBox(size: objectBound)]))
                    object.components.set(InputTargetComponent())

                    animation = object.availableAnimations[0]
                    content.add(object)
                }
            }
            catch {
                print("Error loading the model")
            }
        }
    }
}

但是，当我使用第二个 USDZ 文件时（只需更改实体名称），

1. 模型无法加载，要解决此问题，我必须将

   object

   类型更改为

   Entity

   ，即使加载程序是 ModelEntity.load(named: "object") 并带有警告：内部没有发生“异步”操作“等待”表情。
2. 但是实体就没有

   .mesh.bounds.extents

   了。碰撞不起作用
3. 作为

   Entity

   ，现在 availableAnimations[0] 可以工作了！

所以现在代码变成了

struct ImmrsiveView: View {

    @State var object: Entity? = nil
    @State var animation: AnimationResource? = nil

    var body: some View {
        RealityView { content in
            do {
                object = try await ModelEntity.load(named: "object2")

                if let object {

                    // This doesn't work
                    // let objectBound = object.model!.mesh.bounds.extents
                    // object.components.set(CollisionComponent(shapes: [.generateBox(size: objectBound)]))
                    // object.components.set(InputTargetComponent())

                    animation = object.availableAnimations[0]
                    content.add(object)
                }
            }
            catch {
                print("Error loading the model")
            }
        }
    }
}

问题是......假设有不同的方式加载 USDZ 文件：

1. 如何消除警告？
2. 如何修复第二个对象的碰撞？

Answer 1

请使用

ModelEntity

类型：

import SwiftUI
import RealityKit

struct ContentView: View {
    @State var object = ModelEntity()
    @State var animation: AnimationResource? = nil

    var body: some View {
        RealityView { rvc in
            do {
                object = try await ModelEntity(named: "Man")
                object.position.z = -3.0
                object.name = "Character"    
                object.generateCollisionShapes(recursive: false)
                object.components.set(InputTargetComponent())
                animation = object.availableAnimations[0].repeat()
                object.playAnimation(animation!)
                rvc.add(object)                  
                print(object.model?.mesh.bounds.extents as Any)
            }
            catch {
                print("Error loading the model")
            }
        }
        .gesture(gesture)
    }       
    var gesture: some Gesture {
        TapGesture()
            .targetedToEntity(object)
            .onEnded {
                print($0.entity.name)
            }
    }
}