Abstract: A method of displaying on a graphic display a representation of a rotary body to be machined according to a machining program, the rotary body having a rotation axis about which the body rotates, in which an external cross-sectional shape of the body in a plane of the rotation axis is displayed in accordance with stored point data representing an external, closed line denoting the cross-sectional shape. Projected surfaces of the body and recessed surfaces of the body along the external line are represented by predetermined shading data dependent on the location of the respective surfaces with respect to the rotation axis and intervening surface lines.

Abstract: In a display apparatus equipped with a plurality of frame memories for keeping data to be used for display on a display section and an output logic for outputting the display data on the frame memories to the display section, for effective use to various CAD/CAM graphic applications, a switching operation for connection of the frame memories to the output logic is selectively effected through a software among a mode for connecting one of the frame memories to the output logic, a double-buffer mode for switching two of the frame memories at the timing of vertical retrace intervals and a mode for switching the plurality of frame memories at the timing of horizontal retrace intervals.

Abstract: A lathe cutting simulation method comprises the steps of preparing workpiece shading drawing data from workpiece shape data, displaying the shape of the workpiece by using the drawing data, computing the positions of the workpiece and tools on the basis of the input workpiece and tools information and updating workpiece shape data, updating the drawing data on the basis of the updated shape data, and displaying the entire workpiece based upon the updated drawing data.

Abstract: A dynamic simulation system in which an internal model is dynamically changed according to input data. The status of variation of the internal model is inputted, and the display and/or sound output of the internal model is dynamically changed according to the status of variation thus inputted. In the dynamic simulation, not only the state of a model is displayed, but also the status of variation of the model is outputted as display data or sound data. Accordingly, the operator can readily recognize the amounts of variation calculated during simulation.