Lighting with Paint
Lighting is a fundamental aspect of computer cinematography that involves the placement and configuration of lights to establish mood and enhance storytelling. This process is labor intensive, as lighting artist repeatedly adjusts the parameters of a large set of complex lights in order to achieve a desired effect. Typical lighting controls affect the final image only indirectly, requiring a large number of trials to obtain a suitable result.
To address this challenge we present an interactive system wherein a lighting designer paints the desired effects of lights directly into the scene, and the computer finds the best settings of the parameters required to achieve that desired look. For example, the artist can paint color, light shape, shadows, highlights, and reflections using a set of tools suitable for painting lighting effects into a scene.
Our system matches these effects by casting the problem as a high-dimensional search that is solved by a nonlinear optimizer made robust by a combination of initial estimates, system design and user-guided optimization. Previous work on painting lighting has not permitted the lights to move, allowing for linear optimization but preventing its use for lighting in computer animation.
To demonstrate our approach we lit several scenes, mainly using a direct illumination renderer designed for computer cinematography, but also including examples of global illumination and non-photorealistic rendering styles. We show that painting interfaces for lighting design can be used to quickly produce high quality lighting setups, providing major benefits in the artist's workflow.