[]把场景中的对像删除，就会报错

Uncaught TypeError: Cannot read property 'visible' of null
    at RenderSprite3D.__proto._childs (Main.max.js?r0.22069932534774384:33147)
    at RenderSprite3D.__proto._graphics (Main.max.js?r0.22069932534774384:33079)
    at NpcView.__proto.render (Main.max.js?r0.22069932534774384:54362)
    at RenderSprite3D.__proto._childs (Main.max.js?r0.22069932534774384:33147)
    at Sprite.__proto.render (Main.max.js?r0.22069932534774384:54362)
    at RenderSprite3D.__proto._childs (Main.max.js?r0.22069932534774384:33147)
    at SceneView.__proto.render (Main.max.js?r0.22069932534774384:54362)
    at RenderSprite3D.__proto._childs (Main.max.js?r0.22069932534774384:33147)
    at RenderSprite3D.__proto._transform (Main.max.js?r0.22069932534774384:53206)
    at Stage.__proto.render (Main.max.js?r0.22069932534774384:54362)