Nightly

dist/preview release/babylon.max.js

@@ -27154,10 +27154,15 @@ var BABYLON;
             return this;
         };
         VertexData.prototype._mergeElement = function (source, other) {
-            if (!other)
-                return source;
-            if (!source)
-                return other;
+            if (!other && !source) {
+                return null;
+            }
+            if (!other) {
+                return this._mergeElement(source, new Float32Array(source.length));
+            }
+            if (!source) {
+                return this._mergeElement(new Float32Array(other.length), other);
+            }
             var len = other.length + source.length;
             var isSrcTypedArray = source instanceof Float32Array;
             var isOthTypedArray = other instanceof Float32Array;

dist/preview release/customConfigurations/minimalGLTFViewer/babylon.max.js

@@ -27154,10 +27154,15 @@ var BABYLON;
             return this;
         };
         VertexData.prototype._mergeElement = function (source, other) {
-            if (!other)
-                return source;
-            if (!source)
-                return other;
+            if (!other && !source) {
+                return null;
+            }
+            if (!other) {
+                return this._mergeElement(source, new Float32Array(source.length));
+            }
+            if (!source) {
+                return this._mergeElement(new Float32Array(other.length), other);
+            }
             var len = other.length + source.length;
             var isSrcTypedArray = source instanceof Float32Array;
             var isOthTypedArray = other instanceof Float32Array;
@@ -75669,7 +75674,9 @@ var BABYLON;
                 this.removePendingData(this);
             };
             GLTFLoader.prototype._onError = function (message) {
-                this._errorCallback(message);
+                if (this._errorCallback) {
+                    this._errorCallback(message);
+                }
                 this.dispose();
             };
             GLTFLoader.prototype._onProgress = function (event) {

dist/preview release/loaders/babylon.glTF2FileLoader.js

@@ -410,7 +410,9 @@ var BABYLON;
                 this.removePendingData(this);
             };
             GLTFLoader.prototype._onError = function (message) {
-                this._errorCallback(message);
+                if (this._errorCallback) {
+                    this._errorCallback(message);
+                }
                 this.dispose();
             };
             GLTFLoader.prototype._onProgress = function (event) {

dist/preview release/loaders/babylon.glTFFileLoader.js

@@ -2568,7 +2568,9 @@ var BABYLON;
                 this.removePendingData(this);
             };
             GLTFLoader.prototype._onError = function (message) {
-                this._errorCallback(message);
+                if (this._errorCallback) {
+                    this._errorCallback(message);
+                }
                 this.dispose();
             };
             GLTFLoader.prototype._onProgress = function (event) {

dist/preview release/loaders/babylonjs.loaders.js

@@ -3520,7 +3520,9 @@ var BABYLON;
                 this.removePendingData(this);
             };
             GLTFLoader.prototype._onError = function (message) {
-                this._errorCallback(message);
+                if (this._errorCallback) {
+                    this._errorCallback(message);
+                }
                 this.dispose();
             };
             GLTFLoader.prototype._onProgress = function (event) {

loaders/src/glTF/2.0/babylon.glTFLoader.ts

@@ -114,7 +114,9 @@ module BABYLON.GLTF2 {
         }
 
         private _onError(message: string): void {
-            this._errorCallback(message);
+            if (this._errorCallback) {
+                this._errorCallback(message);
+            }
             this.dispose();
         }
 

src/Mesh/babylon.mesh.vertexData.ts

@@ -325,8 +325,17 @@
         }
 
         private _mergeElement(source: number[] | Float32Array, other: number[] | Float32Array): number[] | Float32Array {
-            if (!other) return source;
-            if (!source) return other;
+            if (!other && !source) {
+                return null;
+            }
+
+            if (!other) {
+                return this._mergeElement(source, new Float32Array(source.length));
+            }
+
+            if (!source) {
+                return this._mergeElement(new Float32Array(other.length), other);
+            }
 
             var len = other.length + source.length;
             var isSrcTypedArray = source instanceof Float32Array;