[LayaAirIDE 2.0]给模型动态添加脚本报错

想给一个模型添加一个脚本 一直报错怎么搞？
 
代码片段：
 
import goldItemNode from "../prefabs/goldItemNode";
 
 var sp = Laya.Loader.getRes("res/res3D/prefabsModel/hanbao.lh");
                goldNode = this.scene_3d.addChild(sp);
                goldNode.transform.localPosition = new Laya.Vector3(this.startPos.x + (4.5 - Math.random() * 9), this.startPos.y, this.startPos.z + (2.5 - Math.random() * 5));
                console.log('----------------goldnode', goldNode);
                this.playerGoldArr.push(goldNode);
                goldNode.addComponent(goldItemNode);
 
 
报错信息：
Uncaught TypeError: Cannot read property 'scene' of null
    at goldItemNode._onAdded (libs/laya.core.js:13226)
    at goldItemNode._onAdded (libs/laya.d3.js:10592)
    at Sprite3D._addComponentInstance (libs/laya.core.js:13244)
    at Sprite3D.addComponent (libs/laya.core.js:13291)
    at game_scene.showPlayerGold (js/bundle.js:278)
    at game_scene.onPreLoadFinish (js/bundle.js:210)
    at Handler.runWith (libs/laya.core.js:1009)
    at libs/laya.core.js:19086
    at Handler.runWith (libs/laya.core.js:1011)
    at ResInfo.<anonymous> (libs/laya.core.js:19116)
 
bundle 第278行信息：
var sp = Laya.Loader.getRes("res/res3D/prefabsModel/hanbao.lh");
                    goldNode = this.scene_3d.addChild(sp);
                    goldNode.transform.

localPosition = new Laya.Vector3(this.startPos.x + (4.5 - Math.random() * 9), this.startPos.y, this.startPos.z + (2.5 - Math.random() * 5));
                    console.log('----------------goldnode', goldNode);
                    this.playerGoldArr.push(goldNode);
                    goldNode.addComponent(goldItemNode); //278