From IFWiki

Sense-passing is a simulationist technique that determines what the player-character can see, hear, and smell by working out how far light, sound, and scent can travel from their originating objects. Such a system might allow the player-character to automatically overhear a conversation being held in the next room, smell garlic being kept in a paper sack, and so on, without the author specially implementing each of those events individually.