A part of having good game AI is having the AI characters react to other parts of the game in a realistic way. For example, let's say you have an AI character in a scene searching for something, such as the player to attack them or items to collect (as in the demo in this chapter). We could have a simple proximity check, for example, if the enemy is 10 units from the player, it starts attacking. However, what if the enemy wasn't looking in the direction of the player and wouldn't be able to see or hear the player in real life? Having the enemy attack then is very unrealistic. We need to be able to set up more realistic and configurable sensors for our AI.

To set up senses for our characters, we will use RAIN's senses system. You might assume that we will use standard methods to query a scene in Unity, such as performing picking through Unity's ray casting methods. This works for simple cases, but RAIN has several advanced features to configure sensors for more realism...