Abstract:
The present invention provides an apparatus which displays a plan wiring diagram and three-dimensional layout diagram by associating them with each other so that they can be viewed easily. A apparatus for displaying wiring includes a first storage for storing an image of a plan wiring diagram which shows parts and wirings and a second storage for storing a three-dimensional layout of an apparatus which incorporates the parts and the wirings, and a third storage for storing intermediate images transitional between a starting image in the plan wiring diagram and an ending image of a shape of the corresponding wiring in the three-dimensional layout. A processor displays the plan wiring diagram on the display device by retrieving the plan wiring diagram from the first storage based on a user&#39;s selection, and retrieves the intermediate images of a wiring from the third storage when the wiring is selected from the plan wiring diagram and displays transitions to the shape shown in the three-dimensional layout.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an apparatus for displaying wiring which can graphically display correspondence between a plan wiring diagram of an electric circuit and a geographical layout diagram which represents layout of wirings in an actual machine or apparatus. 
         [0003]    2. Description of the Related Art 
         [0004]    Instruction manuals such as automotive service manuals contain a plan wiring diagram showing an electrical system and a three-dimensional layout diagram showing a geographical layout of wirings in illustrations of an automobile. Both manuals are referred to during servicing of the automobile. 
         [0005]    Recently, plan wiring diagrams and geographical layout diagrams have become very complicated leading to a practice of referring to a service manual on a display screen. The service manual is converted into an electronic form. In a service manual in electronic form, a wiring diagram and a circuit board with electronic components mounted are displayed together in a split display screen or a position in the layout diagram corresponding to a position selected by a user in the plan wiring diagram is displayed in a different color, for example, as shown in Japanese Patent Application Publication No. 2005-4726. 
         [0006]    However, plan wiring diagrams represent electrical relationships among components of an electrical system while three-dimensional layout diagrams represent relationships between positions and wirings of parts. The two types of diagram differ completely in the form of expression. It is difficult to watch the two diagrams alternately by shifting one&#39;s line of sight and understand the correspondence between the two diagrams. 
         [0007]    In automobiles, wirings are often bundled into a wiring harness. Difficulty is also encountered in finding out where the plurality of wirings contained in the harness is located in a plan wiring diagram. Further, a single wiring connector or a single electrical component with multiple functions may be split into multiple portions and is displayed at multiple locations in a plan wiring diagram. This makes it difficult to recognize the wiring connector or electrical component. When similar parts are placed in a concentrated manner such as when a plurality of electronic control units (ECU) are placed in layers, it is not easy to distinguish the parts. 
       SUMMARY OF THE INVENTION 
       [0008]    An object of the present invention is to provide an apparatus which can display a plan wiring diagram and three-dimensional layout diagram by associating them with each other so that they can be viewed easily. 
         [0009]    To achieve the above object, the present invention provides an apparatus for displaying wiring. The apparatus comprises a first storage adapted to store an image of a plan wiring diagram which shows parts and wirings, a second storage adapted to store a three-dimensional layout diagram of an apparatus which incorporates the parts and the wirings, and a third storage adapted to store intermediate images which are transitional between a starting image and an ending image. Each of the wirings shown in the plan wiring diagram is a starting image and the shape of a corresponding wiring in the three-dimensional layout diagram is an ending image. 
         [0010]    The apparatus further comprises a processor adapted to display images on a display device. The processor displays the plan wiring diagram on the display device by retrieving the plan wiring diagram from the first storage based on user&#39;s selection, and retrieves intermediate images of a wiring from the third storage when the wiring is selected from the plan wiring diagram and displays continuous transition until the wiring is illustrated by a shape in the three-dimensional layout diagram. 
         [0011]    Since continuous transition of the wiring the user selected from the plan wiring diagram is displayed until the wiring takes the three-dimensional shape in the three-dimensional layout diagram, the present invention can make it easy for the user to recognize correspondence between the plan wiring diagram and three-dimensional layout diagram. 
         [0012]    According to one aspect of the present invention, the apparatus for displaying wiring further comprises a forth storage adapted to store positions and shapes of the parts in the plan wiring diagram in association with three-dimensional positions and three-dimensional shapes of the parts in the three-dimensional layout diagram. The processor displays the plan wiring diagram on the display device by retrieving the plan wiring diagram from the first storage based on a user&#39;s selection, and retrieves the three-dimensional position and three-dimensional shape of a part from the fourth storage when the part is selected from the plan wiring diagram for displaying the part superimposed over the three-dimensional layout diagram. 
         [0013]    According to the present invention, since the three-dimensional shape of the part selected from the plan wiring diagram by the user is retrieved and superimposed over the three-dimensional layout diagram. Thus, the user may recognize correspondence between the plan wiring diagram and three-dimensional layout diagram. 
         [0014]    According to an embodiment of the present invention, the plan wiring diagram is formed superimposing on a general underlying drawing of the wirings layers of the respective wirings. Intermediate images are provided for each layer. 
         [0015]    According to another embodiment of the present invention, the intermediate images are generated by morphing. 
         [0016]    According to another embodiment of the present invention, while displaying the intermediate images of the selected wiring, the processor erases the general underlying drawing of the wirings and retrieves and gradually displays a general underlying drawing of a corresponding three-dimensional layout on the display. 
         [0017]    According to another form of the present invention, an apparatus for displaying wiring comprises a first storage adapted to store an image of a plan wiring diagram which shows parts and wirings, a second storage adapted to store a three-dimensional layout diagram of an apparatus which incorporates the parts and the wirings, and a third storage adapted to store intermediate images transitional between a starting image and an ending image. The three-dimensional layout diagram is the starting image and the plan wiring diagram is the ending image. 
         [0018]    The apparatus includes a processor adapted to display images on a display device. The processor displays the three-dimensional layout diagram on the display device by retrieving the three-dimensional layout diagram from the second storage based on a user&#39;s selection, and retrieves the intermediate images of a wiring from the third storage when the wiring is selected from the three-dimensional layout diagram. Continuous transition is displayed until the wire Appears in the plan wiring diagram. 
         [0019]    Since transition of the wiring selected from the three-dimensional layout diagram by the user is displayed until the wire Assumes the shape and position in the plan wiring diagram, the user may recognize correspondence between the three-dimensional layout diagram and plan wiring diagram. 
         [0020]    According to an embodiment of the present invention, the apparatus for displaying wiring further comprises a forth storage adapted to store positions and shapes of the parts in the plan wiring diagram in association with three-dimensional positions and shapes of the parts in the three-dimensional layout diagram. The processor displays the three-dimensional layout diagram on the display device by retrieving the three-dimensional layout diagram from the second storage based on a user&#39;s selection. The processor retrieves the position and shape of a part in the plan wiring diagram from the fourth storage when the part is selected from the three-dimensional layout diagram and displays the part at a corresponding position in the plan wiring diagram. 
         [0021]    According to this embodiment, since the part selected from the three-dimensional layout diagram by the user is displayed at the position and in the shape of the part in the plan wiring diagram, the user may recognize correspondence between the three-dimensional layout diagram and plan wiring diagram. 
         [0022]    According to another embodiment of the present invention, the three-dimensional layout diagram is formed of superimposition of a general underlying drawing of a three-dimensional layout and layers of individual wirings. The intermediate images are provided for each layer. 
         [0023]    According to another embodiment of the present invention, the plan wiring diagram is formed of superimposition of a general underlying drawing of the wirings and layers of the respective wirings. 
         [0024]    According to another embodiment of the present invention, the intermediate images represent transitions which take place before a plurality of wires bundled into a harness shown in the three-dimensional layout diagram are displayed as wirings in the plan wiring diagram. 
         [0025]    According to another embodiment of the present invention, when the plurality of wires bundled into a harness correspond to a plurality of drawings in the plan wiring diagram, the processor displays identification information about the plurality of drawings. When one of the drawings is selected, the processor displays intermediate images for the selected drawing on the display. 
         [0026]    According to another embodiment of the present invention, the intermediate images are generated by morphing. 
         [0027]    According to another embodiment of the present invention, while displaying the intermediate images of the selected wiring, the processor erases the general underlying drawing of the three-dimensional layout diagram and gradually displays a general drawing of a plan wiring diagram containing the corresponding wiring on the display. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  is a block diagram showing an overall configuration of a apparatus for displaying wire According to the present invention. 
           [0029]      FIG. 2  is a diagram showing how transitions which take place from a plan wiring diagram to a three-dimensional layout diagram. 
           [0030]      FIG. 3  is a stop-motion diagram showing a mechanism of transitions from a plan wiring diagram to a three-dimensional layout diagram. 
           [0031]      FIG. 4  is a stop-motion diagram showing a mechanism of transitions from a three-dimensional layout diagram to a plan wiring diagram. 
           [0032]      FIG. 5  is a diagram showing a relationship between a plan wiring diagram and three-dimensional layout diagram where a single part is split into two portions in the plan wiring diagram. 
           [0033]      FIG. 6  is a diagram showing an example of correspondence between a three-dimensional layout diagram and plan wiring diagram of a harness containing multiple wires. 
           [0034]      FIG. 7  is a diagram showing an example of transitions from a three-dimensional layout diagram to a plan wiring diagram when the transitions involve rotation of the three-dimensional diagram. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0035]    Embodiments of the present invention will be described with reference to the drawings. An apparatus for displaying wire According to the present invention is implemented when a computer program created for the present invention is installed on a general purpose computer such as a personal computer. In its basic configuration, the computer includes a processor (CPU), a random access memory (RAM) which provides a working area for the processor and temporarily stores programs and data, a non-volatile storage device such as a disk drive which stores computer programs and data, a display device such as a CRT display and a liquid crystal display for displaying computer output, and input devices such as a keyboard and mouse. 
         [0036]      FIG. 1  is a block diagram showing an overall configuration of the apparatus for displaying wire According to the present invention. A disk storage device  10  stores an electronic manual  11  for automobile servicing. The electronic manual  11  includes data stored in a menu screen data storage  11 A for the electronic manual, underlying-drawing data storage  11 B for a plan wiring diagram linked to the menu screen data storage  11 A. The manual further includes planar layer data storage  11 C for storing planar layers for each wiring, intermediate image data storage  11 D for storing intermediate images which represent transitions in wiring shape from the shape in the plan wiring diagram to the shape in a three-dimensional layout diagram and conversely from the three-dimensional shape in the three-dimensional layout diagram to the shape in the plan wiring diagram. The manual also includes data storage  11 E for storing three-dimensional layer for each wire and data storage  11 F for storing underlying drawing of the three-dimensional layout diagram. 
         [0037]    The processor  20  realizes a function of displaying wire According to the present invention with the disk storage device  10 , display device  30 , and input devices  40 . When a user starts the computer of the apparatus and selects the program for the electronic manual, the processor  20  activates the program for the electronic manual ( 21 ). Consequently, a menu of the electronic manual is displayed on the display device  30  ( 23 ). Since the electronic manual itself is publicly known, detailed description is omitted. When the user selects a fuel injection system (PGM-FI), brake system (ABS), headlight system, or the like and selects a page of a plan wiring diagram ( 25 ) in accordance with the menus and using input devices  40  such as the keyboard and mouse, a plan wiring diagram is retrieved and displayed on the display device  30  ( 27 ). 
         [0038]      FIG. 2  is a diagram illustrating how display on the display device  30  changes from a plan view to a three-dimensional view. Block  41  shows an example of a plan view displayed on the display device  30 . The plan view is formed by superimposing layers of individual wirings and parts retrieved from the data storage  11 C over a underlying layer containing all the wirings, which is retrieved from the data storage  11 B in  FIG. 1 . For example, if the number of wirings and parts is thirty, thirty-one layers consisting of thirty wiring layers plus one underlying layer are superimposed and displayed as a plan view on the display device  30 . 
         [0039]    If the user selects wire A by placing a cursor on wire A in the plan view and clicking the mouse or entering a part number of wire A via an input device  40  ( 29 ), the layer of wire A is superimposed over the underlying drawing of all the wirings. The wire A is highlighted by bold lines or by color. Next, when the user pushes a confirmation button (not shown) displayed on a screen of the display device  30 , for example, by clicking the button with a mouse, wire A changes its shape gradually to a three-dimensional shape as shown in block  46  through intermediate images  7  ( FIG. 2 ). The three dimensional shape is superimposed over an underlying drawing of a three-dimensional layout retrieved from data storage  11 F storing the three-dimensional underlying drawings. 
         [0040]    The speed of transition may be adjusted using a scroll bar  49 . 
         [0041]      FIG. 3  illustrates stop-motion transitions. First, a plan view  41  selected by the user is displayed on the display device  30 , which comprises an underlying drawing retrieved from the data storage  11 B and superimposed layers of multiple wirings retrieved from data storage  11 C. When the user selects wire A from the wiring diagram in the manner described above, a layer  47  of wire A is superimposed over an image  41  of the plan wiring diagram, wire A being highlighted by bold lines or by color. Next, the intermediate images of the layer  47  are retrieved from the intermediate image data storage  11 D to represent transitions to a corresponding layer  48  in the three-dimensional layout diagram ( 33 ). 
         [0042]    In the meantime, the underlying drawing of the three-dimensional layout diagram disappears gradually from a display screen, resulting in a blank image  42  ( 31 ). At the same time, an image  46  appears gradually on the display screen with the layer  48  of wire A being superimposed over the underlying drawing of the three-dimensional layout of the automobile retrieved from the storage  11 F ( 35 ). Then, multiple layers of three-dimensional diagrams of the wirings contained in the underlying drawing are retrieved from the data storage  11 E and superimposed over the underlying drawing to complete the image  46  of the three-dimensional layout diagram in which wire A is highlighted ( 35 ). 
         [0043]    The layer of each wiring is linked to the underlying drawing using a part number and superimposed over the underlying drawing in such a way as to take an appropriate position on the underlying drawing. 
         [0044]    The intermediate images used here are generated using a morphing technique. The morphing technique generates moving-image data which represents smooth transitions from a still image to another still image and is used in the field of animation. Morphing software products are commercially available. The morphing technique handles images in GIF, JPEG, TIFF, PNG, and other file formats. 
         [0045]    In one example, wire A and part B connected to wire A are selected. When wire A and part B are selected, a layer  43  of part B (e.g., an electronic control unit ECU) and layer  47  of wire A are highlighted. Transition of part B into a three-dimensional layer  44  is represented by intermediate images, which are produced by the morphing technique. The three-dimensional layer  44  of part B is superimposed over the underlying drawing of the three-dimensional layout diagram of the automobile to resulting in the three-dimensional layout diagram  46 . In this way, wire A and part B connected to wire A are superimposed over the underlying drawing of the three-dimensional layout diagram. 
         [0046]      FIG. 5  shows an embodiment of one application of the present invention. In a plan wiring diagram, a single connector, unit, or pin is sometimes split into multiple portions for convenience. In  FIG. 5 , a single connector C is split into connector C 1  and connector C 2  in the plan wiring diagram (A). Connectors C 1  and C 2 , which actually are connector C as illustrated in the three-dimensional layout diagram. In this case, when the user selects connector C 1  from the plan wiring diagram (A), both connectors C 1  and C 2  are highlighted and transitions from the plan wiring diagram (A) to the three-dimensional layout diagram (B) are displayed on the display device  30  using an animated display created by morphing technique described with reference to  FIG. 3 . Connectors C 1  and C 2  are displayed in the three-dimensional layout diagram (B) as connector C which is a single part. 
         [0047]    According to a second aspect of the present invention, transitions from a three-dimensional layout diagram to a plan wiring diagram are displayed continuously. Returning to  FIG. 1 , when the user starts the program of the electronic manual ( 21 ) and selects, for example, the three-dimensional layout diagram  46  shown in  FIG. 2  from the menu of the electronic manual ( 23 ), an appropriate underlying drawing is retrieved from the three-dimensional underlying-drawing data storage  11 F. Three-dimensional layers of a plurality of appropriate wirings are retrieved from the three-dimensional layer data storage  11 E, and the three-dimensional layout diagram  46  is displayed on the display device  30  as a superimposition of the underlying drawing and multiple three-dimensional layers ( 27 ). When the user selects wire A by placing the cursor on wire A in the three-dimensional layout diagram  46  and clicking the mouse or by entering the part number of wire A with an input device  40 , the layer of wire A is superimposed over the underlying drawing of the general three-dimensional layout diagram. Wire A is highlighted by bold lines or by color. 
         [0048]    Next, when the user pushs the Confirmation button displayed on the screen of the display device  30 , for example, by clicking the button with a mouse, the underlying drawing of the plan wiring diagram including wire A is retrieved from the planar underlying-drawing data storage  11 B, the layers of multiple wirings contained in the underlying drawing are retrieved from the planar layer data storage  11 C, and a stack of the underlying drawing and the layers appears gradually on the display device  30  as the image  41  of the plan wiring diagram. Then, the intermediate images  7  of wire A in the three-dimensional layout diagram  46  are retrieved from the intermediate image data storage  11 D to display transitions continuously until wire A takes the shape shown in the plan wiring diagram. Eventually, the layer of wire A is superimposed over the underlying drawing of the plan wiring diagram to complete the image  41 . 
         [0049]    Consequently, the image  41  of the plan wiring diagram is displayed on the display device  30  with wire A highlighted. In parallel with this operation, the image  46  of the three-dimensional layout diagram fades out as it is thinned gradually. 
         [0050]    The speed of transition from image  46  to image  41  can be adjusted using the scroll bar  49  displayed on the screen of the display device  30 . 
         [0051]      FIG. 4  illustrates stop-motion view of such transition. The transition flow is opposite in direction to the one shown in  FIG. 3 . First, the three-dimensional layout diagram  46  selected from the menu by the user is displayed on the display device  30 . The three-dimensional layout diagram  46  includes the underlying drawing retrieved from the three-dimensional underlying-drawing data storage  11 F. Multiple layers illustrating the wirings and parts included in the structure of the underlying drawing are retrieved from the planar layer data storage  11 C and superimposed. 
         [0052]    When the user selects wire A from the three-dimensional layout diagram in the manner described above, the layer  48  of wire A is highlighted by bold lines or by color. Next, the intermediate images of the layer  48  are retrieved from the intermediate image data storage  11 D to continuously display transition to a corresponding layer  47  in the three-dimensional layout diagram ( 33 ). Consequently, the shape of wire A in the layer  48  changes gradually to the shape of wire A in the layer  47  of the plan wiring diagram. Meanwhile, the layers in the underlying drawing of the three-dimensional layout diagram disappear gradually from the display screen, resulting in a blank image  45  ( 31 ). An underlying drawing of the plan wiring diagram including wire A is retrieved from the planar underlying-drawing data storage  11 B and appears gradually on the display screen ( 35 ). At the same time, the layers of the other wirings and parts contained in the underlying drawing are retrieved from the planar layer data storage  11 C and eventually superimposed over the underlying drawing.  FIG. 4  illustrates a case in which wire A and part B that is connected to wire A are selected, as in the case of  FIG. 3 . 
         [0053]    Referring now to  FIG. 6 , the user selects a three-dimensional layout view such as shown in  FIG. 6(A) , out of the electronic manual ( 25 ) for display on the display device  30 . When the user places the cursor on a harness E, a bundle of wires, in the drawing and clicks the mouse ( 29 ), the processor  20  displays transition from the harness to the plan wiring diagram using intermediate images. In this case, each of multiple wires contained in the harness has its transition to a plan wiring diagram. In the example of  FIG. 6(B) , the plan wiring diagrams of wires  1 ,  2 , and  3  are displayed on the display device. 
         [0054]    In one example, when harness E is selected in  FIG. 6(A) , types of wires contained in the harness are presented in text form on the display to specify to which system the sires belong, for example, a fuel injection system, a headlight system, etc. Regarding the type of wiring selected by the user, transition to the plan wiring diagram are displayed. The other types of wiring, unless selected, do not have their transition to the plan wiring diagram displayed. Thus, a functional part which needs to be checked may be displayed on a single screen in an easy-to-view fashion, reducing the amount of data for intermediate images greatly. In this case, a combination of part numbers at each wiring connection in the plan wiring diagram is associated with the harness. 
         [0055]      FIG. 7  shows a variation of the second aspect of the present invention. When the user places the cursor on wire F in the three-dimensional view as shown in  FIG. 7(A)  and clicks the mouse, the processor  20  rotates the three-dimensional view from (A) to (B), and then from (B) to (C). In  FIG. 7(C)  wire F appears in the front of the view. The processor  20  displays transition to a plan wiring diagram (D) which contains wire F beginning with the image in  FIG. 7(C)  and using intermediate images. As a plan wiring diagram is associated with the three-dimensional view, the amount of data needed to create the intermediate images may be greatly reduced. 
         [0056]    Next, another embodiment of the present invention will be described. Referring to  FIG. 2 , when the user selects part B in the plan wiring diagram by placing the cursor on part B and clicking the mouse or by entering a part number of part B via the input device  40  ( 29 ), only the layer of part B is superimposed over the underlying layers of all the wirings and is highlighted by bold lines or by color. When the user pushed the confirmation button displayed on the screen of the display device  30 , for example, by clicking the button with a mouse, part B changes its shape gradually to a three-dimensional shape via intermediate images  7 . The three dimensional view is shown in block  46 . The layer of part B is superimposed over an underlying layer of three-dimensional view retrieved from the three-dimensional underlying-drawing data storage  11 F. 
         [0057]    The speed of transition can be adjusted by sliding the button of the scroll bar  49 . 
         [0058]      FIG. 3  shows stop-motion transition. First, a plan wiring diagram  41  selected by the user is displayed on the display device  30 . Layers of multiple wirings retrieved from the planar layer data storage  11 C are superimposed over an underlying drawing retrieved from the planar underlying-drawing data storage  11 B. When the user selects part B from the wiring diagram in the manner described above, the layer  43  of part B is displayed over an image  41  of the plan wiring diagram. Part B is highlighted by bold lines or by color. Next, the intermediate images of the layer  43  are retrieved from the intermediate image data storage  11 D and transition to a corresponding layer  44  in the three-dimensional diagram is displayed ( 33 ). 
         [0059]    In parallel, the underlying layer of the plan view disappears gradually from the display screen, resulting in a blank image  42  ( 31 ). At the same time, an image  46  appears gradually on the display screen with the layer  44  of part B superimposed over the underlying layer of the three-dimensional view of the automobile retrieved from the three-dimensional underlying-drawing data storage  11 F ( 35 ). Multiple layers of three-dimensional view of the wirings contained in the underlying drawing are retrieved from the three-dimensional layer data storage  11 E and are superimposed over the underlying layer resulting in the image  46  of the three-dimensional view in which part B is highlighted ( 35 ). 
         [0060]    The layer of each part or wiring is linked to the underlying layer using a part number and is superimposed over the underlying layer to align with the underlying layer. 
         [0061]    The intermediate images used here are generated using a morphing technique. The morphing technique generates moving-image data which represents smooth transition from a still image to another still image and is used in the field of animation. Morphing software products are commercially available. The morphing technique handles images in GIF, JPEG, TIFF, PNG, and other file formats. 
         [0062]    In one example, part B and wire A connected to part B are selected. When part B and wire A are selected, the layer  47  of wire A connected to part B as well as the layer  43  of part B are highlighted. Intermediate images are produced by the morphing technique to show the manner wire A changes to a shape in a three-dimensional layer  48 . The three-dimensional layer  48  of wire A is superimposed over the underlying layer of the three-dimensional view of the automobile to form the three-dimensional view  46 . In this way, part B and wire A that is connected to part B are displayed together in the three-dimensional view. 
         [0063]    According to one aspect of the present invention, transition from a part selected from a three-dimensional layout to a shape in a plan wiring diagram is sequentially displayed. Returning to  FIG. 1 , when the user starts the program of the electronic manual ( 21 ) and selects, for example, the three-dimensional layout  46  shown in  FIG. 2  from the menu of the electronic manual ( 23 ), an appropriate underlying drawing is retrieved from the three-dimensional underlying-drawing data storage  11 F. Three-dimensional layers of a plurality of appropriate parts and wirings are retrieved from the three-dimensional layer data storage  11 E, and superimposed over the underlying layer to form the three-dimensional layout  46 , which is displayed on the display device  30  ( 27 ). When the user selects part B by placing the cursor on part B in the three-dimensional layout diagram  46  and clicking the mouse or by entering the part number of part B via an input device  40 , the layer of part B is superimposed over the underlying drawing of the entire plan wiring diagram. Part B is highlighted by bold lines or by color. 
         [0064]    Next, when the user pushes the Confirmation button (not shown) displayed on the screen of the display device  30 , for example, by clicking the button with a mouse, the underlying drawing of the plan wiring diagram including part B is retrieved from the planar underlying-drawing data storage  11 B. The layers of multiple parts and wirings contained in the underlying drawing are retrieved from the planar layer data storage  11 C and superimposed over the underlying drawing layer. The layers appear gradually on the display device  30  as the image  41  of the plan wiring diagram. The intermediate images  7  of part B layer in the three-dimensional layout diagram  46  are retrieved from the intermediate image data storage  11 D to display transition of part B. Eventually, the layer of part B is superimposed over the underlying drawing of the plan wiring diagram to complete the image  41 . 
         [0065]    Consequently, the image  41  of the plan wiring diagram is displayed on the display device  30  with part B highlighted. The image  46  of the three-dimensional layout fades out by thinning. 
         [0066]    The speed of transition from the image  46  to the image  41  can be adjusted by sliding the button of the scroll bar  49  displayed on the screen of the display device  30 . 
         [0067]      FIG. 4  shows display stop-motion transition. The transition flow is opposite in direction to the one shown in  FIG. 3 . First, the three-dimensional layout  46  selected from the menu by the user is displayed on the display device  30 . The three-dimensional layout  46  includes the underlying drawing retrieved from the three-dimensional underlying-drawing data storage  11 F. Multiple layers of the parts and wirings contained in the underlying drawing are retrieved from the layer storage  11 C and superimposed over the underlying drawing. 
         [0068]    When the user selects part B from the three-dimensional layout in the manner described above, the layer  44  of part B is highlighted by bold lines or by color. The intermediate images of the layer  44  are retrieved from the intermediate image data storage  11 D to display transition to the corresponding layer  43  in the plan wiring layout ( 33 ). The shape of part B in the layer  44  changes gradually to the shape of part B in the layer  43  of the plan wiring view. Meanwhile, the layer in the underlying drawing of the three-dimensional layout disappears gradually from the display screen, resulting in a blank image  45  ( 31 ). The underlying drawing of the plan view including part B is retrieved from the planar underlying-drawing data storage  11 B and appears gradually on the display screen ( 35 ). At the same time, the layers of the other wirings and parts contained in the underlying drawing are retrieved from the planar layer data storage  11 C and superimposed over the underlying drawing. 
         [0069]    Incidentally,  FIG. 4  shows a case in which part B and wire A that is connected to part B are selected, as in the case of  FIG. 3 . In the example of  FIG. 5 , connector C is split into connector C 1  and connector C 2  in the plan wiring diagram (A). Connector C is displayed as a single part in the three-dimensional layout diagram (B). Conversely, connector C may be selected in the three-dimensional layout diagram (B) and displayed in the plan wiring diagram (A) as split into connectors C 1  and C 2 . 
         [0070]    The present invention has been described above by citing concrete examples, but it should be noted that the present invention is not limited to these concrete examples.