如果你是要在代码设置刚体的属性的话：
let ball = this.scene.getChildByName('ball') as Laya.MeshSprite3D;
let ballRigidboy = ball.getComponent(Laya.Rigidbody3D) as Laya.Rigidbody3D;
ballRigidboy.friction = 1;
ballRigidboy.rollingFriction = 1;
ballRigidboy.restitution =1;
拿到精灵节点，从精灵节点拿到刚体组件。
