Vision is a core mechanic of Invisible Inc. - being able to see guards is crucial, so that you can ensure that they cannot see you.

Entities that have vision will have an vision arc and a vision range. Their vision arc's center point is the center of the entity's tile (with the exception of Security Cameras, whose center is at the corner of the room that it is mounted in), and the bisector of the arc is the line that starts from the center of the arc and travels in the direction that the entity is facing. The vision range is the diameter of this arc.

Vision cannot travel through hard cover or tall cover; any point that does not have a straight line to the center of the vision cone that doesn't pass through hard cover or tall cover is not seen.

A tile is visible to an entity if it has vision on at least 45% of its area.