Try fixing Build

Tools/Gulp/config.json

@@ -66,7 +66,7 @@
             "distOutputDirectory": "/",
             "dtsBundle": {
                 "name": "babylonjs",
-                "main": "../../dist/preview release/build/src/index.d.ts",
+                "main": "../../dist/preview release/build/index.d.ts",
                 "out": "../babylon.module.d.ts",
                 "baseDir": "../../dist/preview release/build/",
                 "headerText": "BabylonJS"

src/webpack.config.js

@@ -21,7 +21,9 @@ module.exports = {
         //devtoolModuleFilenameTemplate: "[absolute-resource-path]"
     },
     resolve: {
-        extensions: [".js", '.ts']
+        modules: ['./'],
+        extensions: ['.ts'],
+        mainFields: []
     },
     externals: {
         babylonjs: {