Abstract: In order to display a portion of a physical structure on a screen, an intermediate "pointer" memory is created. The addresses of memory words in the pointer memory correspond to the coordinates of pixels on a display screen, or in equivalent manner to the corresponding addresses of memory words in an image memory. The information loaded into the memory words of the pointer memory is representative of addresses in an "original" memory whose collection of memory words represents the structure under investigation. It is shown that by using the pointer memory it is possible for each voxel of the structure to establish quickly the coordinates of the position at which it ought to appear on the screen, and thus the address of the corresponding memory words in the pointer memory, by using previously-calculated memory addresses for the pointer memory.