This paper describes multi-user autostereoscopic displays developed within the European Union-funded MUTED and HELIUM3D projects. These utilize head tracking in order to provide images that are displayed in regions referred to as exit pupils that follow the users' eye positions. In the MUTED displays images are produced on a direct-view liquid crystal display (LCD) with novel optics controlled by the head tracker replacing the conventional backlight. This paper describes the design and construction of the displays along with evaluation results and future developments. The principle of operation, the current status and the multimodal potential of the HELIUM3D display is described.