an improved apparatus forms three - dimensional objects in layers by modulating irradiation of liquid photopolymers , either stepwise by alternating photopolymer deposition and irradiation , or continuously by simultaneous deposition and irradiation . photopolymer is deposited onto open , unfenced and uncontained , substrate and is contained by a photopolymer wall formed around the object simultaneously with it by supplemental irradiation , for providing to irradiated layer unobstructed access critical to apparatus simplification , automation , fabrication time and to feasibility of continuous forming . to decrease drastically fabrication time , whole layer is irradiated simultaneously using masks photoplotted on a roll of film or a matrix of miniature individually controlled components tightly packed similar to liquid - crystal displays , with shrinkage distortion minimized by constraining the irradiated photopolymer surface and / or by solidifying infinitely thin surfaces in continuous mode .