如何提高RealityKit物理模拟精度？

Question

我一直试图建立一个基于RealityKit的Billiard游戏，但是物理模拟还不够精确。当参数太小时，RealityKit似乎会产生粗略的计算结果。

下面的代码介绍了我到目前为止所做的工作。有办法配置RealityKit并提高物理精度吗？

import RealityKit
import ARKit

let ballMaterial = PhysicsMaterialResource.generate(friction: 0.055, restitution: 0.95)

game.allBalls.forEach { entity in
    guard let physicsEntity = entity as? HasPhysics else { return }
    
    physicsEntity.physicsBody?.massProperties.mass = 0.17
    physicsEntity.physicsBody?.material = ballMaterial
}

let wallMaterial = PhysicsMaterialResource.generate(friction: 0.005, restitution: 0.5)

game.wallEntities.forEach { entity in
    guard let physicsEntity = entity as? HasPhysics else { return }
    
    physicsEntity.physicsBody?.material = wallMaterial
}

let tableSurfaceMatrial = PhysicsMaterialResource.generate(staticFriction: 0.001, dynamicFriction: 0.2, restitution: 0.25)

game.tableSurfaceEntities.forEach { entity in
    guard let physicsEntity = entity as? HasPhysics else { return }
    
    physicsEntity.physicsBody?.material = tableSurfaceMatrial
}

增加移动白色球的力量：

// ballWhite as? Entity & HasPhysics
game.ballWhite.physicsBody?.mode = .dynamic
game.ballWhite.addForce(rayForce, relativeTo: nil)

ModelEntity:渲染物理实体

HasPhysics:物理协议

落球

Answer 1

如果将restitution参数设置为大于1的值，则RealityKit物理引擎开始产生更逼真的弹跳模拟，但在动态效应衰减时仍然不够真实--苹果工程师必须更加努力地在RealityKit 3.0中实现健壮的物理模拟。

我用了一个简单的真实作曲场景，里面有一个半径为0.1米的球。

import AppKit
import RealityKit

class GameViewController: NSViewController {
    
    @IBOutlet var arView: ARView!
    
    override func awakeFromNib() {

        arView.environment.background = .color(.black)
        
        let ballScene = try! Experience.loadBall()

        let ball = ballScene.sphere!.children[0] as! ModelEntity
        
        ball.components[CollisionComponent.self] = 
                        CollisionComponent(shapes: [.generateSphere(radius: 0.1)], 
                                             mode: .default, 
                                           filter: .sensor)

        ball.components[PhysicsBodyComponent.self] = 
                        PhysicsBodyComponent(shapes: [.generateSphere(radius: 0.1)], 
                                               mass: 0.05, 
                                           material: .generate(friction: 0.9, 
                                                            restitution: 1.35))
        
        arView.scene.anchors.append(ballScene)
    }
}

​

​