Updated JSONLoader to allow material-less data.

src/loaders/JSONLoader.js

@@ -419,6 +419,12 @@ THREE.JSONLoader.prototype.parse = function ( json, texturePath ) {
 
 	};
 
+	if ( json.materials === undefined ) {
+
+		return { geometry: geometry };
+
+	} else {
+
 		var materials = this.initMaterials( json.materials, texturePath );
 
 		if ( this.needsTangents( materials ) ) {
@@ -427,9 +433,8 @@ THREE.JSONLoader.prototype.parse = function ( json, texturePath ) {
 
 		}
 
-	return {
-		geometry: geometry,
-		materials: materials
-	};
+		return { geometry: geometry, materials: materials };
+
+	}
 
 };