A three-dimensional printing system includes a support plate, a transparent sheet, gas pressure source, and a conduit. The support plate includes a transparent central portion and defines a gas inlet and a gas outlet. The transparent sheet overlays the transparent central portion, the gas inlet, and the gas outlet of the support plate. A central chamber is defined between the transparent sheet and the support plate. The gas pressure source is coupled to the gas inlet through the conduit. An input fluid flow resistance Li is defined from the gas pressure source to the central chamber. An output fluid flow resistance Lo is defined out through the gas outlet and to an outside location. A ratio of Li to Lo is sufficient to allow a stable control of a physical configuration of the central unsupported portion of the transparent sheet above the support plate.