Toward Evaluating Lighting Design Interface Paradigms for Novice Users
W. Kerr, F. Pellacini
ACM Transactions on Graphics (SIGGRAPH 2009), 2009
Lighting design is a complex but fundamental task in computer cinematography, involving the adjustment of light parameters to define final scene appearance. Many user interfaces have been proposed to simplify lighting design. They can be generally categorized in three paradigms: direct light parameter manipulation, indirect light feature manipulation (e.g., shadow dragging), and goal-based optimization of lighting through painting. To this date, no formal evaluation of the relative effectiveness of these paradigms has been performed.
In this paper, we present a first step toward evaluating the benefits of these three paradigms in the form of a user study with a focus on novice users. 20 subjects participated in the experiment by performing various trials on simple scenes with up to 8 point lights, designed to test two lighting tasks: precise adjustment of lighting and the artistic exploration of lighting configurations. We collected objective and subjective data and found that subjects can light well with direct and indirect interfaces, preferring the latter. Paint-based goal specification was found to be significantly worse than the other paradigms, especially since users tend to sketch rather than accurately paint goal images, an input that painting algorithms were not designed for. We also found that given enough time, novices can perform relatively complex lighting tasks, unhindered by geometry or lighting complexity. Finally, we believe that our study will impact the design of future lighting interfaces and it will serve as the basis for designing additional experiments to reach a comprehensive evaluation of lighting interfaces.