[]laya core 报错了

laya.core.js:5779 Uncaught TypeError: Cannot read property 'visible' of null
    at RenderSprite3D.__proto._childs (laya.core.js:5779)
    at RenderSprite3D.__proto._transform (laya.webgl.js:5779)
    at Stage.__proto.render (laya.core.js:14540)
    at Stage.__proto.render (laya.core.js:17340)
    at Stage.__proto._loop (laya.core.js:17274)
    at loop (laya.core.js:5061)

麻烦上传一个有问题的例子，仅凭描述和报错信息看不出来问题！