A method of forming a three-dimensional object comprises ejecting drops of liquefied material into a vat using an ejector; scanning the ejector in first and second mutually opposed directions to induce the drops of liquefied material from the ejector to deposit and solidify in a predetermined sequence to sequentially form layers of the three-dimensional object; supplying a viscous liquid into the vat to a level which is essentially level with the top of a most recently formed layer of the three-dimensional object; and raising the level of the viscous liquid in accordance with the formation of new layers.