1. A non-transitory machine readable memory storing computer executable instructions, comprising: instructions for configuring a computer, wherein the computer is capable of performing computation operations in parallel on up to a pre-determined number of data elements, to perform a method comprising selecting rays from a plurality rays stored on a tangible medium to be processed in a parallelized computing operation, the selecting based on a set of stored data correlating the plurality of rays with respective elements of a hierarchical acceleration structure, for which definition data is stored on a tangible medium coupled for reading by the computer, and updating the set of stored data to maintain correlations between rays of the plurality with respective elements of the hierarchical acceleration structure, based on results of the parallelized-computing operation, wherein each element of the hierarchical acceleration structure bounds a set of primitives located in the 3-D scene, and the selecting further comprises selecting rays of the plurality by determining that each of the selected rays needs to be tested for intersection with primitives bounded by one or more of the elements of the hierarchical acceleration structure, pending exclusion from possible intersection based on results of one or more further parallelized computing operations with those selected rays.