A method of generating and processing models of two-dimensional or three-dimensional objects in a computer and of reproducing said models on a display

Claim 1

A CAD-system using a method of generating and processing models of two or three dimensional objects in a computer and of reproducing said models on a display, - in which said models are built up by means of geometric operations such as moving, rotating, enlarging, reducing and/or Boolean operations, such as connecting, forming points of intersection, in accordance with the user's instructions, from elements whose shapes are already determined by data stored in or input into the system, it being possible for said elements in turn to be built up from elements of a lower hierarchical level, - in which a menu of commands is shown on the display outside the image of the model so that the user can select specific command by marking the associated place on the menu with a pointer whose position is controllable by the user by means of an inputting device, or select a specific lowest level element by marking a point within said element on the image using said pointer and - in that there is stored for each element in each hierarchical level a word and also data concerning the hierarchical relationship between said element and hierarchically higher and lower elements, characterised - in that a structure diagram is reproduced on the display, together with the image of the model, in which diagram each element is indicated by its word at a place corresponding to the element to which it belongs, and - in that when the user marks a word in the structure diagram with the pointer the appropriate element and all its comprised lower level elements are selected, and any operation to be carried out is carried out on said element and all said comprised lower level elements.