A method is disclosed for additive manufacturing a three-dimensional object layer-by-layer including depositing a layer of material on a bed surface or a previously deposited layer of the object to form the object layer-by-layer; providing energy to the material after each layer is deposited with the energy being provided by an energy source that forms an energized beam directed at the material; altering a property of a gas surrounding the material and through which the energized beam extends to alter a property of the object constructed from the material; melting the material with the energized beam to form a melted pool of liquefied material; and allowing the material to solidify to bond the material to a previous layer of material of the object.