Reconfigurable computer generated holography - sometimes known as electroholography - is the only technique capable of using computer held data to generate interactive, high quality, 3D images containing all the depth cues used by the human visual system. Practical applications of electroholography require computer generated hologram (CGH) patterns of between 10/sup 9/ to 10/sup 10/ pixels to be calculated and displayed at interactive rates. These pixel counts are necessary in order to generate images which are both big enough (upwards of 300 mm width) and possess a large enough field of view (FOV) to permit simultaneous, multiuser viewing. Advances in several key areas may now make such high performance electroholographic systems practical in the near future. We describe CGH design algorithms, computer architectures and CGH display engines, including the Active Tiling/spl trade/ system.