The presence measure experiment of Chapter 4 made use of a standard PC and ``Virtual TV'' (VTV) software from Warp, Ltd.  which allows a very large image to be stored in memory. The VTV software ``precomput[es] the rendering of a scene from all possible view orientations. This permits unlimited pan/tilt/roll/zoom freedom at high framerates on standard VGA cards.''  Instead of dynamically computing updates to the visual scene, oscillations were implemented more efficiently by indexing into different portions of the image. This allowed for a frame-rate of 60 Hz. Unfortunately, it also meant that the scene could not be displayed in stereo: the same indexed image was sent to both eyes of the HMD. To keep the frame-rate consistently at 60 Hz in all conditions, an ``approximate dewarp'' mode was used, which does not precisely simulate oscillations around a fixed center-point. For the same reason, a rather low resolution of 240x320 pixels was used.
The reported presence/foreground occlusion research reported in Chapter 5 made use of the Division ProVision 100. The ProVision 100 is a hardware/software platform designed specifically for supporting virtual environments. It combines an Intel 486 platform with dedicated stereo graphics, three-dimensional audio, and low-latency virtual world interactivity in a single chassis. It can be accessed by standard UNIX applications. It comes with dVS, Division's software environment, which provides a distributed foundation for applications and a high level object-oriented programming interface. It is used in conjunction with the Division dVisor HMD described below.
The environment used for the research described in Chapter 5 was ``SharkWorld''. ``SharkWorld'' was developed by Division, Ltd. and features a texture-mapped underwater scene with a sunken ship and various moving sea creatures. The participants tried to catch sharks using a virtual net which followed real hand position.
The research involving control reversals (see Appendix C) made use of images generated by a Silicon Graphics Reality Engine II and displayed on a Silicon Graphics 20'' monitor.