Real-Time Lighting Design for Interactive Narrative

Lighting design is an important element of scene composition. Designers use lighting to influence viewers’ perception by evoking moods, directing their gaze to important areas, and conveying dramatic tension. Lighting is a very time consuming task; designers typically spend hours manipulating lights’ colors, positions, and angles to create a lighting design that accommodates dramatic action and tension. Such manual design is inappropriate for interactive narrative, because the spatial and dramatic characteristics of an interactive scene, including dramatic tension, camera location, and character actions, change unpredictably, necessitating continual redesign as the scene progresses. In this paper, we present a lighting design system, called ELE (Expressive Lighting Engine), that automatically, in real-time, adjusts angles, positions, and colors of lights to accommodate the dramatic and spatial characteristics of a scene, while conforming to the established style and ensuring visual continuity. ELE uses constraintbased non-linear optimization algorithms to configure lights using cost functions formulated based on traditional film and theatrical lighting design theory.