Abstract: In one embodiment, a stack of individual images of a scene are created. Each individual image corresponds to a respective light source or light source group associated with the scene. The individual images are combined to produce a combined image. The combined image is displayed. In response to user input indicating adjustments to a light source or light source group, an operator is applied to a corresponding individual image of the stack of individual images. An updated combined image is displayed on the display screen. Values for light sources or light source groups are generated based on the applied operator. The generated values are provided to a design session in a modeling environment.