ARKit：球没有穿过SCNTorus洞

问题描述：

我在ARKit上遇到问题，我需要帮助。我正在做一个小演示，我在场景中放置一个简单的SCNTorus几何体，并且试图将一个小球（SCNSphere）扔进圆环孔。问题在于球在中间弹跳而不是通过。没有为环面的代码：ARKit：球没有穿过SCNTorus洞

 let ring = SCNTorus(ringRadius: 0.4, pipeRadius: 0.1) 
    ring.ringSegmentCount = 100 

    let ringMaterial = SCNMaterial() 
    ringMaterial.diffuse.contents = UIImage(named: "art.scnassets/Ball/BeachBallColor.jpg") 

    ring.materials = [ringMaterial] 

    let ringNode = SCNNode() 
    ringNode.position = SCNVector3(
     x: location.worldTransform.columns.3.x, 
     y:location.worldTransform.columns.3.y + 0.8, 
     z: location.worldTransform.columns.3.z 
    ) 

    ringNode.geometry = ring 

    let body = SCNPhysicsBody(type: SCNPhysicsBodyType.kinematic, 
           shape: nil) 
    body.categoryBitMask = CollisionTypes.wall.rawValue 
    body.collisionBitMask = CollisionTypes.beachball.rawValue 
    // body.contactTestBitMask = CollisionTypes.beachball.rawValue 
    body.isAffectedByGravity = false 
    body.mass = 0.5 

    ringNode.physicsBody = body 

    sceneView.scene.rootNode.addChildNode(ringNode)

而对于球：

let node = SCNNode(geometry: sphere!) 
    node.renderingOrder = 10 

    let body = SCNPhysicsBody(type: SCNPhysicsBodyType.dynamic,shape: nil) 
    body.categoryBitMask = CollisionTypes.beachball.rawValue 
    body.collisionBitMask = CollisionTypes.solid.rawValue|CollisionTypes.wall.rawValue|CollisionTypes.beachball.rawValue 
    // body.contactTestBitMask = CollisionTypes.fireball.rawValue|CollisionTypes.wall.rawValue 
    body.isAffectedByGravity = true 
    body.mass = 0.5 
    body.restitution = 0.75 
    body.damping = 0.1 
    body.friction = 0.8 

    node.physicsBody = body

可能的重复：https：//stackoverflow.com/q/27391763/957768 – rickster

答

使用创建physicsbody（体型kinametic和形状无）以简化的“凸结果的代码船体“几何形状的表示。简而言之，您看到的几何体是圆环面，但用于碰撞检测的几何体不是。

的（OBJ C）这行代码实际上是从苹果的示例代码项目之一：

_torus.physicsBody = [SCNPhysicsBody bodyWithType:SCNPhysicsBodyTypeStatic shape:[SCNPhysicsShape shapeWithGeometry:_torus.geometry options: @{SCNPhysicsShapeTypeKey : SCNPhysicsShapeTypeConcavePolyhedron} ] ];

换句话说，你需要根据几何自己创建一个静态类型的身体和形状使用SCNPhysicsShapeTypeConcavePolyhedron键值（仅适用于静态物体）最终以环体几何形状的更精确表示作为物理体。

有关详细信息，请参阅：https://developer.apple.com/documentation/scenekit/scnphysicsshape

答

谢谢！这行得通！有代码：

let ring = SCNTorus(ringRadius: 0.4, pipeRadius: 0.1) 
    ringNode.geometry = ring 

    let shapeOptions = [ SCNPhysicsShape.Option.type : SCNPhysicsShape.ShapeType.concavePolyhedron] 
    let physicShape = SCNPhysicsShape(geometry: ring, options: shapeOptions) 

    let body = SCNPhysicsBody(type: SCNPhysicsBodyType.kinematic, 
           shape: physicShape) 
    body.categoryBitMask = CollisionTypes.wall.rawValue 
    body.collisionBitMask = CollisionTypes.beachball.rawValue 
    body.isAffectedByGravity = false 
    body.mass = 0.5 
    ringNode.physicsBody = body

ARKit：球没有穿过SCNTorus洞

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