The document discusses modeling perception and awareness for NPCs in the video game Splinter Cell: Blacklist. It describes four models of perception for NPCs: visual, environmental, auditory, and social/contextual perception. The document outlines challenges in implementing these perception models, such as inconsistent player feedback when tuning visual detection and audio perception issues and solutions. Overall the goal was to create NPCs with perceptive abilities that feel fair, provide consistent feedback to the player, and behave intelligently based on their awareness of surroundings.