A method includes assigning a priority to a ray data structure of a plurality of ray data structures based on one or more priorities. The ray data structure includes properties of a ray to be traced from an illumination source in a three-dimensional image. The method includes identifying a portion of the three-dimensional image through which the ray passes. The method also includes identifying a slave processing element associated with the portion of the three-dimensional image. The method further includes sending the ray data structure to the slave processing element.