Abstract: This paper describes a parallel ray tracing system MAGG which has 86 transputers and HDTV frame buffers. Our system is based on a screen subdivision algorithm. In this algorithm, each processor essentially requires entire scene database. Therefore huge local storage should be required if the scene is complicated. In order to avoid this, shape descriptions in a scene database should be transferred to the processor whenthey are required. However, it would lead to lower parallel processing performance.We have devised fast communication between the large shared memory and the local memory on each processor by means of DMA transfer instead of serial link transfer. Some experimental results indicate it is effective to improve the efficiency of parallel processing.