1. A method, comprising: performing a ray-primitive intersection search for one or more of rays in parallel by a graphics processing unit (GPU) for a scene containing more data than the GPU can allocate in its own physical memory; and organizing a ray-primitive intersection search process using several iterations of at least the following operations executed in each iteration: compute ray-primitive intersections for one or more rays in parallel by the GPU using portions of scene data available in GPU memory and request for portions of scene data that are not currently in GPU memory but are necessary for ray-primitive intersection search; and deliver requested portions of scene data to GPU memory excluding those portions of scene data that have already been loaded to GPU memory within one of the previous iterations of ray-primitive intersection search process.