Field of View is a component that helps to implement visualization of the area visible by the character. With its help, it is possible to implement game mechanics nicely represented by stealth-oriented real-time tactics games.
Documentation | Unity Forum
Field of View component has the following features:
● works nicely in 3D mode;
● can be individually/in bulk configured for any number of characters;
● is not static, it simulates the behavior of real character who can look around, seek for someone, etc;
● supports three modes of rotation:
1. ‘calm’ patrol, if no targets have appeared in the Field of View;
2. ‘peer’ on a target, whenever it is inside the Field of View area;