code: function (x, y, z) {
              y = (typeof (y) !== "undefined" ? y : x);
              z = (typeof (z) !== "undefined" ? z : x);
              return this._set(this.x * x, this.y * y, this.z * z);
          }
docs: Multiply this vector values by the given scalar
  @name scale
  @memberOf me.Vector3d
  @function
  @param {Number} x
  @param {Number} [y=x]
  @param {Number} [z=x]
  @return {me.Vector3d} Reference to this object for method chaining