Powder layer smoothing devices (34) adapted for use with powder-layer three-dimensional printers (10) are described. The smoothing devices (34) include a counter rotating roller (36, 50, 60) having a complex powder engaging face (38) that may include a series or plurality of flutes (54) or may include knurling (64) extending along at least a portion of the counter rotating roller (36, 50, 60) along its rotational axis (56, 66). The smoothing device (34) may also include a vertically adjustable finishing roller (35) to follow the counter rotating roller (36, 50, 60) across the build box (12) of the powder-layer three-dimensional printer (10).