An apparatus for adding isopleths to image data includes an input device for sequentially inputting image data to be displayed on an image screen of a display device, a horizontal delay circuit for delaying the inputted data by one horizontal scanning period, a column comparator for comparing the inputted data, that is, a sample, with a delayed sample from the horizontal delay circuit to thereby generate a signal indicating a sample to be converted into isopleth data, a sample delay circuit for delaying the sample outputted from the horizontal delay circuit by one sampling period, a row comparator for comparing the sample outputted from the horizontal delay circuit with the sample outputted from the sample delay circuit to thereby generate a signal indicating a sample to be converted into isopleth data, and an isoplete data generator responsive to the output of the column and row comparators for replacing the indicated input sample by predetermined distinguishable data and for outputting the predetermined distinguishable data to the display device.

An apparatus for measuring a figure distance between first and second points of a solid figure with a measuring device having first and second panels and an axis connecting the panels is provided with a measuring device data storing section for storing attribute data and constitutional data of the measuring device, a solid figure data storing section for storing solid figure data, and a display section for displaying the measuring device and the solid figure according to the data stored in the storing sections, a moving section for positioning the first and second panels at the first and second points according to a motion mode, and a renewing section for renewing the data according to an editing mode. In the moving section, the axis is extended or shortened, translation movement is performed for the measuring device, and/or the panels is deformed in a stick shape according to the motion mode. In the renewing section, the measuring device is rotated or jointed to a second measuring device, one of the panels is overlapped with a surface or an edge of the solid figure, and/or the axis is curved to measure a curved outline length of the solid figure according to the editing mode.

A transparent board-like digitizer is placed near a display screen. Images of the same size as that of the digitizer images entered on the digitizer are displayed on the screen. A co-ordinates standard of the digitizer is set to be identical with that of the screen. Thereby, the point indicated on the digitizer of a first cursor device is shown at a position corresponding to that of the point indicated by the cursor. The screen displays right-angle scale lines controlled by a second cursor device on the digitizer. The right-angle scale lines can carry out parallel movements and rotations on the screen. When a straight line drawing is carried out, an operator indicates two points on the digitizer by means of the first and the second cursor devices and inputs the data of such two points, whereby a straight line connecting these two points, dimension supplemental lines in parallel with the right-angle scaling lines, dimension lines extending between the two points, and a dimension figure, respectively, are displayed on the screen.

A CAD/CAM system arranged so that a re-creation processing for a cutter path is automatically executed by a CAM system when a curved surface is modified by a CAD system. Functions for the cutter path re-creation processing are provided by utilizing a customizing function of the CAD system. In executing computation for the cutter path and in originating NC data, references for assigning the functions are previously set for the curved surface. When the shape of the curved surface is modified on the CAD side after the NC data has been created, the CAM is invoked to invoke the aforesaid functions. Perceiving this invocation, the CAM executes the cutter path re-creation processing by using machining condition data set for the unmodified curved surface, on the basis of the invoked functions. Thus, the cutter path for the modified curved surface is created immediately by the CAM when the curved surface is modified by the CAD.

A specifying unit specifies a plot range and the plot spacing of a diagram represented by a desired function input by an input unit; a correlating unit correlates the specified plot range and plot spacing of the diagram with a position on a display unit; and a plotting unit plots the diagram with arbitrarily spacing on the display unit.