1. The Zone Of View (ZOV)¶
It is important to understand the concept Zone of View ( ZOV ), as it is an essential element of PresenZ. A standard precomputed rendering is often done using a perspective camera projection, which is centered around a point of view ( POV ), the focal point. This type of rendering locks the user’s perspective to the POV. Meaning that after the prerender is done the image doesn’t convey any other information other than seen from the original POV. To translate that to VR, you can’t see any of the objects that are hidden behind what you see. Even if the virtual reality headset has positional tracking. The image itself does not have the information, which is the main cause of cybersickness, discomfort and poor immersion that some people feel.
To put this in contrast. PresenZ makes a render from a zone of view and gathers all the information which is possible to see from within this “zone”. The ZOV is a volume box with a default size of 1 by 1 meter with a height of 0,5 meters, but this can be adjusted as explained in the next chapter. The user running the PresenZ Viewer, can move freely inside the zone of view’s volume and have a proper perspective change on the pre-rendered 3D scene.
While the user is inside the ZOV, he/she can look in any direction they want.
When the user is outside of the ZOV, it looks like he is watching through a portal which is projecting the 3D scene. The ZOV position and orientation is given by the rendering camera in the 3D scene.