Abstract: A method of generating and processing models of two-dimensional and three-dimensional objects in a computer and of reproducing the models on a display is presented. The models are created according to the user's instruction by means of geometric operations such as moving, rotating, enlarging, reducing and/or Boolean operations, such as connecting, forming points of intersection, forming points of differentiation, from elements whose shapes are already determined by data stored in or input into the computer. It is possible for these elements in turn to be constructed from elements of a lower hierarchical level. A menu of commands and a pointer whose position is controllable by the user through an inputting device are shown on the display outside the image of the model so that the user can select specific parts of the model and specific commands by marking the associated place on the display with the pointer.