The present invention relates to powder-layer three-dimensional printers (2) having a discrete supply hopper (340) and a recoater (20). The discrete supply hopper (340) is configured to transfer a build powder to the recoater (20) in a manner that enhances the uniformity of build powder layers that are dispensed from the recoater (20). In some embodiments, at least one of the discrete supply hopper and the powder hopper of the recoater is adapted to selectively contact the other, seal against the other, and/or have one partially inserted inside the other so as to diminish or prevent powder pluming during the transfer of build powder from the discrete supply hopper to the recoater.