An analysis on detection from guards in games

Now the movement system has been analysed, designed and implemented, lets look at the next logical step in stealth gameplay: Detection.

With detection, I mean the way that guards or cameras can see you and be alerted. How close can you get to a guard, how far away can he see and how wide is his viewing angle.

How close can the player get to a guard

While a bit of the easier question to answer, it could still proof difficult to not let the player go out of control. This question may heavily depend on your game. In Hitman or Dishonored, it may be required to get close to a guard to eliminate then and take their disguise. Yet in games like PAYDAY 2 or even stealth sections in non-stealth games, it might be critical that the user does not get close to a guard.

When the player should not get close to a guard it should be communicated clearly, perhaps in a tutorial that shows the player another thief getting caught or a simple help text can work as well. The most important thing is that the rules are simple and communicated properly to the player. The alert system should be used here where the guard could “hear” the players footsteps within a given area and makes a remark about that. Do not let the guard turn around instantly, give the player time to escape and do their thing.

Do not forget the rule of consistency here, make sure that all guards or NPCs that can spot the player have the same radius that they will detect the player in.

Types of vision games and/or Unity uses

The types of vision used is not strictly defined within game design. Some games simply check if the playeer is within a given radius of the guard while others have a strict vision cone.

The most popular form of vision is using ray casts to hit an object and detect it.

Bart de Bever
Software Engineer

Student who is inspired by web applications and passion projects for gaming.