BendyLights: Artistic Control of Direct Illumination by Curving Light Rays

Abstract

In computer cinematography, artists routinely use non-physical lighting models to achieve desired appearances. This paper presents BendyLights, a non-physical lighting model where light travels nonlinearly along splines, allowing artists to control light direction and shadow position at different points in the scene independently. Since the light deformation is smoothly defined at all world-space positions, the resulting non-physical lighting effects remain spatially consistent, avoiding the frequent incongruences of many non-physical models. BendyLights are controlled simply by reshaping splines, using familiar interfaces, and require very few parameters. BendyLight control points can be keyframed to support animated lighting effects. We demonstrate BendyLights both in a realtime rendering system for editing and a production renderer for final rendering, where we show that BendyLights can also be used with global illumination.