1. A computer-implemented method for determining illumination of objects over a three-dimensional environment in a visual simulation, the method comprising: producing, by a computer, an illumination map from a raster elevation map for a first illumination area of interest; illuminating the objects in the first illumination area of interest by applying, by the computer, the produced illumination map to the objects of the first illumination area of interest; responsive to a change in the area of interest to a second illumination area of interest, updating, by the computer, at least a portion of the illumination map to illuminate the objects of the second illumination area of interest.