This is a paid asset, but now you can download Field Of View for FREE, but please remember this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Detail this asset from Unity Store: Original Link
Field Of View v1.1
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;
3. ‘cool-down’ after the target has just been gone out of Field of View area;
● supports flexible customisation of rotation patterns;
● supports different timings for target detection and cool-down periods;
● has a very flexible configuration of interaction with the game environment: transparency of every layer can be configured separately;
● allows to style visible Field of View area with colors or textures;
● has editor extension that simplifies the configuration and makes the area visible in both: play and edit modes, thus simplifies the process of level design;
therefore the Field of View behavior can be simulated in a very realistic way.
Field of View has the following limitations:
● Scriptable Render Pipelines (URP or HDRP) are not supported at the moment.