Tracking and the matched zone

• Never allow head tracking to be frozen or delayed; otherwise, the user might immediately perceive self-motion (Section 8.4).
• Make sure that the eye viewpoints are correctly located, considering stereo offsets (Section 3.5), head models (Section 9.1), and locomotion (Section 10.2).
• Beware of obstacles in the real world that do not exist in the virtual world; a warning system may be necessary as the user approaches an obstacle (Section 8.3.1).
• Likewise, beware of obstacles in the virtual world that do not exist in the real world. For example, it may have unwanted consequences if a user decides to poke his head through a wall (Section 8.3.1).
• As the edge of the tracking region is reached, it is more comfortable to gradually reduce contrast and brightness than to simply hold the position fixed (Section 8.4).