sightline

A sightline is the straight line along which an observer has an unobstructed view toward a target. It is defined by the observer’s eye position and the geometry of the surrounding environment. Any intervening object—such as a wall, furniture, vegetation, or a person—can block or alter the view, creating an occlusion. The concept is used across disciplines to analyze visibility, design space, and communicate how line of sight changes with position and height.

In architecture and urban planning, sightlines are assessed to preserve important views, create visual corridors, and guide the placement of buildings, landscapes, and landmarks. Zoning and design guidelines may limit building heights or orientations to maintain a target line of sight, such as toward a scenic feature or tower. Digital tools often simulate sightlines to evaluate the impact of proposed developments before construction.

In theaters, arenas, and cinemas, sightlines describe how well seats permit unobstructed views of a stage or screen. Design considerations include sight angle, seat height, row spacing, and balcony rake, with the goal of minimizing obstructions from railings, columns, or other spectators.

In safety-critical contexts, sightlines affect how quickly a person can perceive a hazard. Road and railway design use minimum sight distance to ensure a driver or operator can stop in time, while aviation and maritime operations rely on clear line-of-sight for navigation and control.

In media and interactive media, sightlines influence composition and storytelling. In photography and film, the observed eye line helps guide viewers; in video games and simulations, line-of-sight checks determine whether a character can see a target, influencing AI behavior and rendering through occlusion culling.