Three.js: 编辑：未捕获的TypeError：normal.clone不是函数

问题描述

我将gltf文件导入three.js编辑器，导出时出现此错误

Uncaught TypeError: normal.clone is not a function
at createNormalizedNormalAttribute (GLTFExporter.js:297)
at processMesh (GLTFExporter.js:1240)
at processNode (GLTFExporter.js:1812)
at processNode (GLTFExporter.js:1860)
at processNode (GLTFExporter.js:1860)
at processScene (GLTFExporter.js:1921)
at processInput (GLTFExporter.js:1974)
at GLTFExporter.parse (GLTFExporter.js:2004)
at UIRow. (Menubar.File.js:272)
createNormalizedNormalAttribute @ GLTFExporter.js:297
processMesh @ GLTFExporter.js:1240
processNode @ GLTFExporter.js:1812
processNode @ GLTFExporter.js:1860
processNode @ GLTFExporter.js:1860
processScene @ GLTFExporter.js:1921
processInput @ GLTFExporter.js:1974
parse @ GLTFExporter.js:2004
(anonymous) @ Menubar.File.js:272 

这是文件
https://github.com/zypy333/test1/blob/HEAD/2cen.gltf

Three.js版本

• [x]开发
• [x] r116

浏览器

• [x]全部
• [ ] 铬合金
• []火狐
• [ ] IE浏览器

操作系统

• [x] Windows

硬件要求（图形卡，VR设备等）

不