1. In a computer graphics system for rendering images for display on a human-perceptible display element, the displaying comprising the display of image representations on the display element, wherein (1) the display element is operable to generate a human-perceptible display of a scene in accordance with pixel values generated by the computer graphics system, (2) the computer graphics system is operable to construct ray tracing data tree structures in memory, and (3) the constructing of tree structures includes any of classification and sorting, the improvement comprising: utilizing a termination criterion and memory scheduling heuristic to enable construction of an efficient ray tracing acceleration data tree structure in a given, a priori fixed memory block, the termination criterion and memory scheduling heuristic comprising: transmitting, for use in constructing the acceleration data tree structure, a contiguous portion of memory along with a value representative of the size of the contiguous portion of memory, and instead of terminating the hierarchy by controlling a maximum depth of the tree, constructing a leaf node, if two reference lists resulting from a classification step plus the size of a tree node do not fit into the given memory block; and predicting the memory consumption of the two new sub-trees in the sorting and accordingly distributing the available memory to the left and right children when continuing recursively, the predicting comprising computing a prediction pε[0, 1], which schedules a fraction of memory scheduled for the left child, the remainder of the memory being scheduled for the right child, such that depth is implicitly controlled by the scheduled memory, and the scheduling allows local adaptation of depth.