JPH0614337B2 - How to change the shape model - Google Patents

Description

The present invention relates to a method for creating a shape model in a computer-aided design system or the like, and more specifically, a method for changing the product shape of a vehicle or the like created in a computer system by design change or model change. In particular, the present invention relates to a shape model changing method capable of efficiently handling shape data stored in an enormous database in a minimum range and making desired changes.

In recent years, computer-aided design system (hereinafter CAD / CAM
(Referred to as “)” is becoming widespread and applied to various industrial fields. In particular, CAD / CAM systems that handle three-dimensional shape models are widely applied from the concept stage of design to the simulation of production.

Such CAD / CAM systems are also used in the design of vehicles such as automobiles. Therefore, in the automobile manufacturing field, it is necessary to change the product shape of the vehicle created in the computer system by design change, model change, or the like. Such a shape model is graphic data composed of a free-form surface, and is stored in a database as a huge amount of data. Therefore, it takes a lot of time to process the graphic when changing the shape.

That is, when changing the shape model as described above,
In general, (1) the operator reads the range of the shape part to be changed from the diagram and checks the connection state of the shape parts with the coordinate values on the diagram. For this reason, it takes time to perform the check, which is inefficient, and an oversight error has occurred.

(2) Since the unit to be changed is a surface unit, it is necessary to reduce the entire number of surfaces that change into a change, and there is a request to redefine it to the extent that there is no change. Further, it is necessary to delete various information data related to the surface data and to redefine the data, which causes inconvenience of processing for the shape-changed portion and inconvenience that it takes a long time. The present invention has been made to overcome the above-mentioned inconveniences, and in a changing method for changing a part of a shape model created in a computer system, a huge amount of shape data stored in a database can be efficiently minimized. It is an object of the present invention to provide a method of changing a shape model that can be created within a short range of processing time by making a necessary change by handling within the range.

In order to achieve the above object, the present invention is a method of changing a shape model for changing a part of an entire shape model created in a computer system, wherein the computer system includes a storage device storing the shape model. Including a first step of obtaining a non-matching section by comparing the shape surface data of the whole shape model before the shape change and the new shape line data of the new shape to be changed, and the whole shape model based on the non-matching section Secondly, a range including the shape-changed portion is specified by a cutoff line, and the specified shape part is cut out from the overall shape model.
And a third step of cutting a new shape line newly created in the computer system with the cutting line, a fourth step of obtaining partial shape surface data from the new shape line data, and the partial shape surface A fifth step of embedding in the cut-out portion of the overall shape model.

Next, a method for changing a shape model according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a diagram showing a basic configuration of a computer-aided design system (CAD / CAM) that handles a shape model according to the present invention, and reference numeral 10 stores shape model data or the like indicating a product shape of a vehicle or the like. 3 illustrates an external storage device.

The shape model data of a product or the like, which is a set of related shape surfaces, includes the overall shape model 24, the partial shape model 26, and the line data 28.The overall shape model 24 represents the entire shape to be finally expressed in the shape file. It is data, and there is only one in the shape file.

The overall shape model 24 is composed of a plurality of partial shape models 26. That is, the partial shape model 26 is a representation of a part of the shape of the whole shape model 24, and there can be n pieces in the shape file. The overall shape model 24 is the final shape data to be expressed, whereas the shape expressed by the partial shape model 26 is an intermediate shape of the work, and the changed shape expressing the desired shape change is also this partial shape. model
26. The overall shape model 24 and the partial shape model 26 are handled as processing units handled by a computer in graphic processing, file processing, and display processing. The line data 28 is curve data required in the process of changing the shape, and includes cut line data of the overall shape model 24 and line data of a new shape created when changing the shape.

Reference numeral 12 indicates an electronic computer, which performs a series of processes related to a shape model creation process and a shape change described later. Further, desired shape data is read from the external storage device 10, and the graphic display device 16 displays the data. It controls the stereoscopic image display.

Reference numeral 14 is an interface device, and the computer 12
And an input / output device such as a graphic display device 16, an operation panel (keyboard) 18, and a coordinate input device (tablet) 20. The operation panel 18 is an input operation panel for an operator to input a processing command and a processing parameter to the electronic computer 12, and the coordinate input device 20 allows the operator to use the stylus pen 22 to select the cutting range of the shape changed portion from the entire shape model 24. It is for instructing.

The computer-aided design system according to the present invention is roughly configured as described above. Next, the processing procedure and effect relating to the change of the shape model will be described.

The shape model changing method according to the present invention provides a shape change range from the whole shape model before shape change, partially cuts a figure, and newly creates a shape model to be changed to the cut shape part in the computer system. Basically, this new modified shape model is embedded in the cut-out shape part.

FIG. 2 is a schematic processing flow showing the method of changing the shape model according to the present invention.

In changing the shape model, first, in step A, the line data of the shape changed portion is input to the electronic calculator 12 from the coordinate entering device 20 or the like. Then, in step B,
The non-matching section of the whole shape plane data before the shape change and the new shape line data is checked. That is, the shape model created in the computer 12 is normally taken in as shape line data from the diagram representing the product shape, and the three-dimensional lines are defined as the shape surfaces, and these shape surfaces are connected to each other. It is expressed as a shape model.

Therefore, in order to specify the shape change portion, the shape data before shape change and the new shape data disagreement section are different from the shape before shape change, and that portion is specified and obtained on the graphic display device 16. Next, in step C, the range including the shape-changed portion is specified in the range sufficiently including the shape-changed portion with respect to the whole shape model in which the cut-out portion is specified by the cut line on the whole shape model before the shape change. This creates one closed curve (polygon window) while sequentially defining the cutoff line according to the origin of the shape surface.

Next, in step D, the entire shape model before shape change is cut along the cutting line specified in step C. That is, it is divided into those that leave the divided shape surface in the whole shape model with the cut line and those that exclude it, and further cut the shape surface surrounded by the cut line and the shape surface excluded from the above from the whole shape model .

At this time, the inside of the cutoff line, that is, the left side with respect to the traveling direction of the cutoff line is a shape surface. Next, in step E, the new shape line is cut with the cutting line specified in step C. That is, the new shape line is obtained by finding the shortest position on the line cut by the cut line, and is divided into an effective portion (a line that remains as a shape) and an invalid portion (a line that does not remain as a shape) and the invalid portion is cut out.

Next, in step F, partial shape surface data is obtained from the new shape line data. In other words, the outermost line (cutoff line) of the new shape line and the end point of the shape line that defines each shape surface are linked (joined), and the section line is inserted at the position where the shape surface will be further divided. , Add a link relationship at the intersection.

The outermost line is divided into fine lines at all link positions, and a face loop that traces counterclockwise is taken out based on one side arbitrarily extracted. The space between these lines is obtained as a shape surface. Further, the adjacent shape surfaces are adjacent to each other. This is for associating on the database that the shape surfaces are connected to form one shape.

Finally, in step G, the new shape part is embedded in the cutout part of the whole shape model before the shape change. That is, each shape surface of the partial shape model after the shape change is embedded in the overall shape model. Furthermore, a connection relationship between the embedded shape surface group and the whole model is established.

In general, the process of changing the shape model is performed as described above, and each step will be described in more detail below.

FIG. 3 is a diagram showing a detailed processing procedure of steps A and B in the process of changing the shape model shown in FIG.

When changing the shape, the coordinate input device 20 or the graphic display device 16 is used to instruct the new shape line data A representing the new shape to be changed (STP1). Next, the shape surface group B (B ₁ , B ₂ ) in the overall shape model 24 predicted to be related to the new shape line data A is designated (STP2). In FIG. 3, A is a diagram conceptually showing a new shape line, and B ₁ and B ₂ are conceptual diagrams showing a shape surface in the overall shape model.

When the above data is input to the electronic computer 12, the electronic computer 12 first sets the boundary lines C _{1 to} C ₇ of the shape surface group B (B ₁ , B ₂ ) in the instructed overall shape model. Boundary group C
(STP3), the boundary line group C and the designated new shape line data A are sequentially compared to obtain the new shape line data A.
The boundary line corresponding to is specified (in the example of the figure, the boundary line C ₃ ,
C ₄ ) A coincident section between the two is obtained and set as D (D ₁ , D ₂ ) (STP4). A portion other than the coincident section D of the boundary line C with respect to the new shape line data A is obtained as the non-coincident section E (STP
5) The non-coincidence section data is sent to the graphic display device 16 for graphic display (STP6).

FIG. 4 is a diagram showing a detailed processing procedure of step C in FIG. Step C is a process for identifying a shape-changed portion on the entire shape model, that is, a range including the non-coincidence section obtained in step B by a cut line.
Based on the partial shape model relating to the shape change in the overall shape model displayed in 16 and the non-matching section E between the new shape line A and the boundary line C obtained in step B, the input operation panel 18
Then, the method of creating the cutoff line is selected from types (a) to (c) and input (STP7). Type (a) is the range of 2
This method is used to specify the line a in the conceptual diagram of the figure in FIG. 4 used when a part of the boundary line of the shape surface is specified as a cutoff line by designating the coordinates (P ₁ , P ₂ ) of the points. Done. Type (b) is to specify the coordinates (Q ₁ ) of one point of the line to be extracted, and to trace from the specified point to the boundary line of the shape surface in a certain direction of the constituent line of the surface and specify it as a cut line. use. The identification of the lines b, c, d, e and g, h in the graphic conceptual diagram is performed by this method. Type (c) specifies the coordinates (R _{1 to} R _n ) of _n points along the profile of the line to be extracted, and projects the profile represented by the specified point group on the shape surface to identify the cut line. It is used when The line f in the graphic conceptual diagram is specified by this method (STP8).

When the cutting method is selected in step 7 and the coordinates of the required points are input in step 8, the electronic computer 12 specifies the cutting line according to the above-mentioned method according to each type, and identifies the specified line and the shape surface. Between the shape surface indicating the mutual relationship between the surface and the line existing in the surface shape, that is, with the correlation data indicating the on-surface line, so that it can be used for the subsequent processing (cutting of the partial shape), for example, the storage device 10 It is stored in the work area or the like (STP9).

In the figure conceptual diagram of FIG. 4, the steps 7 to 9 are started from the line a, the partial cutoff lines are sequentially specified in the counterclockwise direction, and when the line h is completed, the specified cutoff lines a to h are closed. Is stored as line data in the storage device 10 (ST
P10).

FIG. 5 is a diagram showing a detailed processing procedure of step D in FIG. Step D is a process of cutting out a partial shape from the whole shape model by the cutting line specified in step C, and the cutting line i obtained by the process shown in FIG.
Is designated from the graphic display device 16 or the coordinate input device 20 (STP11), and then the overall shape model 24 to be cut or the partial shape model j constituting the overall shape model 24 is designated (STP12).

When these inputs are made, the electronic computer 12 searches the specified cutoff line i and the shape model j for the shape surface group k which is in an in-plane relation, and the shape surface 1 which is entirely included in the cutoff line i (STP13). The shape surface groups having the relationship of the on-surface lines obtained in the above step 13 are sequentially subjected to shape surface division along each of the partial cut lines a to h shown in the conceptual diagram of FIG. The schematic diagram of FIG. 5 shows that the shape plane S having the partial cutoff line b on the surface (in the relationship of the on-plane line) is divided into S ₁ and S ₂ by the partial cutoff line b (STP14). Then, a surface to (exclude) each divided shape surface,
It is divided into the side to be left. This is performed by specifying the shape surface inside the cut line i which is one closed line (in this example, the left side in the traveling direction of the cut line) as the surface to be cut (STP15). By sequentially repeating the processing of step 14 and step 15 up to the partial cut lines a to h, all of the shape surfaces having the relationship of the on-plane line are divided by the partial cut lines a to h, and the surface to be cut is specified. As a result, the shape plane 1 whose whole is included in the cut line i from the shape model j to be cut, and the step 1
From the shape surfaces after division obtained in 4 and 15, cut out the shape surface group specified as the shape surface to be cut (STP
16).

FIG. 6 is a diagram showing a detailed processing procedure of step E in FIG. Step E is a process of cutting out the new shape line by the cutting line specified in step C. The cutting line i obtained by the process shown in FIG. 4 is designated from the coordinate input device 20 (STP18), and then changed. A new shape line m forming the shape is designated (STP19). When these inputs are made, the computer 12 obtains the coordinates P _1, P ₂ of the shortest position of the tear line i and the new shape line m (STP20), the coordinates P _1, P a new shape line m calculated in step 20 Part to be cut out by ₂ (ineffective part) n ₁ , n ₃ and part to be left (effective part)
It is divided into n ₂ (STP21). Next, the invalid portions n ₁ and n ₃ are cut out from the new shape line m (STP22). By repeating this process for each new shape line group forming the shape model to be changed, the cutting process of the new shape line is completed.

FIG. 7 is a diagram showing a detailed processing procedure of step F in FIG. Step F is a process of specifying a new shape to be changed, that is, new partial shape surface data from the new shape line data obtained in step E, and creating a shape model to be changed. First, the cutoff line i obtained in the process of FIG. 4 is designated (STP23), and then the new shape line n _i obtained in the process of FIG. 6 is designated (STP24). When this input is made, the computer 12 adds the data indicating the link (binding) related to the intersection of the tear lines i and the new shape line n _i (end point) (STP25). This processing is performed for all new shape lines n _i (n ₁ ~
n ₄₎ is performed for, when this is done, then Wakashi, if there is a portion where the shaped surface is divided by the newly designed line n _i, added to section line in that position. Since the graphic conceptual diagram shown in FIG. 7 shaped surface by new shape line n _2, n ₃ is divided, through the intersection of the new shape line n _2, n _3, leading to the new shape lines n _1, n ₄ A cross section line o is added (STP26). Next, data indicating a link (coupling) relationship is added to the intersections of the cross section line o and the new shape lines n _{1 to} n ₄ (STP27).

When this processing is completed, the electronic computer 12 divides the cut line i, the new shape lines n _{1 to} n ₄ , and the section line o at all link (coupling) positions, and i _{11 to} i ₂₀ , n ₁₁ , n ₁₂ ,
Let n ₄₁ , n ₄₂ , o ₁₁ and o ₁₂ (STP28). Of these dividing lines, based on one arbitrarily extracted line (one side),
Detect the lines that make up the tracing loop in the counterclockwise direction. For example, starting from the divided new shape line n ₁₁ , a closed loop shape line that surrounds one surface with the cutoff line i ₁₃ , the new shape line n ₂ , and the section line o ₁₁ is detected (STP29). next,
The shape surface surrounded by the closed loop shape line is specified (STP30), and when there is an adjacent shape surface,
Data indicating the adjacency relation is added (STP31). This process is sequentially repeated to create shape surface data that forms a new shape model to be changed.

FIG. 8 is a diagram showing a detailed processing procedure of step G in FIG. Step G is a process of embedding the new shape model (new shape surface group) to be changed created in the process of step F in the overall shape model 24 obtained by cutting out the part specified by the cut line in the process of step D.

In this process, first, the overall shape model F obtained by the process of FIG. 5 is designated (STP32). In this overall shape model, the shape portion to be changed is cut out by a cut line. Next, a new partial shape model (new shape surface data group) G to be changed created by the processing of FIG. 8 is designated (STP33). When the overall shape model F and the new partial shape model G are designated in this way, the electronic computer 12 copies each shape surface forming the new partial shape model G to the cut out portion of the overall shape model F, and a new one is created. An overall shape model H whose shape has been changed is obtained (STP34).
Then, data indicating the adjacency relationship between the shape surface group G ′ forming the copied new partial shape model and the overall shape model F is added, and the processing ends.

As described above, the method of changing the shape model according to the present invention checks the shape surface data of the whole shape model before the shape change and the new shape line data constituting the new shape to be changed, and checks the whole shape model. , The range including the shape change part is specified by the cut line, cut from the whole shape model, the new shape line to be changed is cut out, new shape surface data is obtained, and the new shape surface is cut into the whole shape model. Since a new shape model composed of data is embedded, it is possible to search and handle the minimum shape data related to changes from the shape data stored in a huge database, and process only the range of shape changes. Since the shape can be changed with, the processing time can be greatly shortened, and
Since the other shape data not related to the shape change is not affected at all, there is an advantage that the shape database in the computer system can be easily managed.

Although the present invention has been described above with reference to the preferred embodiment, the present invention is not limited to this embodiment and can be applied to a method of newly creating surface data from line data, for example. Of course, various improvements and design changes can be made without departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a basic configuration diagram of a computer-aided design system that handles a shape model according to the present invention, FIG. 2 is a schematic processing flow showing a shape model changing method according to the present invention, and FIG. FIG. 8 to FIG. 8 are diagrams showing the detailed processing procedure of each step of the processing flow shown in FIG. 10 …… External storage device, 12 …… Computer 14 …… Interface device, 16 …… Figure display device 18 …… Operating panel, 20 …… Coordinate input device 22 …… Stylus pen, 24 …… Overall shape model 26… … Partial shape model, 28 …… Line data

Claims (1)

[Claims] 1. A method of changing a shape model for changing a part of an entire shape model created in a computer system, wherein the computer system includes a storage device storing the shape model, and the entire shape model before changing the shape. A first step of comparing the shape surface data of the shape model with new shape line data forming a new shape to be changed to obtain a non-coincidence section, and including a shape modification section on the overall shape model based on the non-coincidence section. A second step of specifying the range with a cutting line and cutting the specified shape part from the overall shape model; a third step of cutting a new shape line newly created in the computer system with the cutting line; It comprises a fourth step of obtaining partial shape surface data from the new shape line data, and a fifth step of embedding the partial shape surface in the cut-out portion of the overall shape model. Changing the shape model is characterized and.