A three-dimensional printing system includes an array of platen sections, a plurality of compressive sheets, a chassis, a plurality of actuators, a powder dispenser, and an energy beam source. The array of platen sections individually have a top surface and a plurality of vertical side surfaces intersecting the top surface. The plurality of platen sections are positioned with adjacent pairs of platen sections having a pair of the vertical side surfaces in facing relation with each other and defining a vertical gap therebetween. Thus they define a plurality of vertical gaps over the array of platen sections. The plurality of compressible sheets fill the plurality of vertical gaps. The chassis supports the array of platen sections. The plurality of actuators is for individually and vertically positioning the platen sections.