[LayaAirIDE 2.0]新人请教一下载入U3D场景的问题，感谢

在main.js中照着官方实例导入U3D场景，但是一直报错，请问一下是什么原因，新人刚学习，还恳请大神们耐心指点指点，谢谢。
 
ReferenceError: enum_btConstraintParams_BT_CONSTRAINT_ERP is not defined
laya.physics3D.runtime.js:364
at a (file:///D:/works/laya/3dTest/bin/libs/laya.physics3D.runtime.js:364:26)
 
at file:///D:/works/laya/3dTest/bin/libs/laya.physics3D.runtime.js:365:96
 
at file:///D:/works/laya/3dTest/bin/libs/laya.physics3D.runtime.js:365:115
 
at Function.Laya3D.init (file:///D:/works/laya/3dTest/bin/libs/laya.d3.js:2143:4)
 
at new Main (file:///D:/works/laya/3dTest/bin/js/bundle.js:75:32)
 
at Object.2../GameConfig (file:///D:/works/laya/3dTest/bin/js/bundle.js:125:1)
 
at o (file:///D:/works/laya/3dTest/bin/js/bundle.js:11:265)
 
at r (file:///D:/works/laya/3dTest/bin/js/bundle.js:11:431)
 
at file:///D:/works/laya/3dTest/bin/js/bundle.js:11:460