JPH03105684A - Solid model generating method - Google Patents

Abstract

PURPOSE:To easily cope with the change of design by combining cubic forms of respective small parts to generate a form model. CONSTITUTION:A computer which has a central processing unit and has functions of graphic calculation, display control, data base management, etc., and a large-cappcity storage device 4 where a large quantity of graphic information is preserved and updated are provided. Plural graphic display devices 8 which are used while interlocking with an input device, a graphic output device 6 like an XY plotter, a tablet 10 connected to each graphic display device 8, a keyboard 12, a mouse 14, a light pen 16, etc., are provided to constitute a system. A solid model is divided into plural form parts to be formed and are joined to form the solid model. Thus, the correspondence to the change of design or the like to individual form parts is very facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Fields] The present invention is directed to computer-aided design systems (hereinafter referred to as CA
This is related to the method of discipline for 3D models in the D system.

[Background of the Invention] Conventionally, when designing an automobile body using a CAD system, an overall model has been constructed as a collection of curves along the curved surface of the vehicle body. Therefore, for example, even if there is a partial design change, it is necessary to process all lines that pass through the changed position, resulting in a problem in that a large amount of time is required to make the design change.

When inputting data into a CAD system, it is necessary to provide the coordinates of vertices and the connections between the vertices in order to define a three-dimensional model.

For example, when inputting a cross section along the a-a line of a part of the front pillar of a car as shown in FIG. 10a into a CAD system,
As shown in Figure 10b, when the front glass surface ■ is input as the reference plane, if the slope of the input line segments ■ to ■ is positive and clockwise with respect to the reference plane, then the value is 10. On the other hand, as shown in Fig. 10C, when the direction of viewing the cross section is reversed compared to Fig. 10a, that is, when the C-C line cross section is manually input to the CAD system, Fig. 1O d As shown in , the slope of the input line segment ■ becomes 2.

In this way, in order to clarify the direction and positional relationship, it is common to use matrix-like auxiliary lines that indicate the direction and distance from the reference point, or to display reference planes common to each small part on the same screen. The method used is to display it above and enter the relative relationship with it to create it.

[Problems to be Solved by the Invention] However, when actually manufacturing images, it is not always the case that images are projected from a certain direction, but are also created upside down or viewed from the back, so the position may vary. , the positive and negative angles will be reversed, and there is a risk of incorrect fabrication unless you have a certain amount of experience. Furthermore, this data input method has the problem that the input work is very time-consuming and it is easy to make mistakes during input.

In addition, when constructing the three-dimensional shape of a product on a CAD system, each individual figure is defined as an element, and then the operator adds relationships between the figures, and the operator breaks down the shape he wants to create into elements and defines them. It required a lot of operations to define each individual element.

Furthermore, the relationships between figures were at the line level, and it was impossible to define them as three-dimensional objects including surfaces.

[Object of the Invention] The present invention has been made to overcome the above-mentioned disadvantages, and includes classifying each part into work units in a three-dimensional model of a vehicle, etc., constructing the three-dimensional model on a CAD system, It is an object of the present invention to provide a three-dimensional model creation method that can easily create a three-dimensional model by assembling and connecting these.

[Means for achieving the object] In order to achieve the above-mentioned object, the present invention provides a method for creating a three-dimensional model using a CAD system, in which the Saibayashi three-dimensional model is divided into a plurality of shape parts and the shape is divided into three-dimensional models. The three-dimensional model is characterized in that a three-dimensional model is formed by joining together the plurality of shaped parts formed by dividing.

[Operations] According to the present invention, a three-dimensional model is constructed by joining a plurality of shaped parts, and it becomes much easier to deal with design changes to individual shaped parts.

[Example] Next, the method for creating a three-dimensional model according to the present invention will be described in detail below with reference to the accompanying drawings, with reference to preferred examples in relation to a device incorporating the method.

As shown in FIG. 1, the CAD system to which this embodiment is applied includes a computer 2 that has a central processing unit and has roles such as graphic calculation, display control, and database management, and a computer 2 that stores and updates a large amount of graphic information. Mass storage device 4 that can
, a plurality of graphic display devices 8 that are central devices for interaction between the CAD system and its users and are used in conjunction with input devices, and graphic output devices 6 such as XY blocks.
, a tablet 10, a keyboard 2, a mouse 14, a light pen 16, and other devices connected to each graphic display device 8.

The CAD system has many programs shown in FIG. Each program has a shared function.
Therefore, it can be classified into the following modules. come.

(a) An operating system 32 and a control module 34 that control processing and information flow within the CAD system; and (c) an input module 44 that assists in smooth input operations using various input devices, such as the keyboard 12. (C) Input interpretation module 40 that interprets manually entered information according to the command format (a) Display module 38 that manages display information and performs display processing according to commands (e) Structured from submodules corresponding to commands (f) a command module 24 that performs graphic processing according to the commands provided; A macro module 28 (b) that executes the Gouram 26 includes an external system interface 30 that exchanges information with other CAD systems and performs interlocking processing.

In addition, in order to maintain expandability and maintainability, the CAD system also includes a system control file 22 that stores system precepts and standard values, a command control file 42 that stores the operability of each command and program control procedures, and a display. Display control file 3 that stores the device model and configuration
6 etc. auxiliary files will be prepared. In addition, as an auxiliary tool, there is a graphic processing library 4 that processes graphics.
6. A display library 48 for displaying on the graphic display device 8, a drawing utility 56 for outputting processing results on the graphic output device 6, a data exchange utility 52 for connecting with other CAD systems, etc. are prepared. be done.

Next, each module will be briefly explained.

The control module 34 modularizes the program group and intervenes between each module to centrally manage control within the system and standardize calling procedures. Its functions include start, end, abnormal handling, execution control of each module, recording of execution history, debugging function, and special processing with the operating system 32.

The input module 44 provides the user with a comfortable input procedure according to specifications that organize and unify various input methods of various input devices. Its functions include prompting the user to instruct the user on the type of information to be input, how to input it, and which manual device to use, selecting the input device, and converting the input information into a standard format.

The input interpretation module 5-40 supports a variety of manual instruction methods, improves input operability, and maintains system expandability by unifying the input information interpretation method and result display. Its functions include interpreting input information and displaying the interpretation results.

The display module 38 uniformly processes various display operation requests and manages display information and display states. Its functions include display device management, display control, display information management, and display state management.

The command module 24 centrally manages input argument formats, calling processing programs according to commands, and processing results, thereby maintaining maintainability and expandability of the system.

The database operation module 50 standardizes the request method from other modules and provides recovery means in the event of a failure. Its functions include management of database usage, operation of the database 54, and processing when a failure occurs. The external system interface standardizes the exchange of information with other systems and makes effective use of the CAD system.

Its functions include exchanging information with external systems and controlling the operation of external programs.

The macro module 5-28 controls the execution of the CAD system according to the created macro program 26. Its functions include translation of macro program 26, macro program 2
This is the execution of step 6.

A method for creating a three-dimensional model using the above-described CAD system will be explained by giving an example. Here, the shapes to be carefully observed below are referred to as building blocks, and these building block patterns are classified as follows.

(1) Section building blocks that create a 3D model with a constant cross-sectional shape (2) View building blocks that create a 3D model that represents a shape viewed from a certain direction (3) Create a shape that connects already defined 3D models Connecting building blocks (4) Knob building blocks that create a patterned attached shape and combine it with the basic shape.The processing includes building block manipulation and building block editing.

First, as an example of section building blocks, a case where a cross-sectional shape of a part of the front pillar of an automobile shown in FIG. 3a is created will be described.

Indicate the cross-sectional direction and cross-sectional area with line segments and ■, and as shown in Figure 3b, specify the reference glass alignment with line segment ■, and then draw the cross-sectional shape of a part of the front door with line segment ■.
Instruct Raa with ~■.

The procedure for inputting such a cross-sectional shape into the CAD system is as shown in Fig. 3b, from line segment ■ to line segment ■, approximately at positions P1 to P7 corresponding to both ends of the line.
Place the cursor on and hit the key to enter. In this case, it is not necessary for each of the line segments (1) to (2) to maintain exactly perpendicular and horizontal positions with respect to the reference line segment, and it is sufficient that the approximate shape thereof is known.

Then, to enter the sloped line segment ■, its? Move the cursor to end positions P7 and P8 and hit the key. Again, it is not necessary to enter the slope angle accurately;
■Rough manual effort is enough to see if it is tilted. In addition,
Input line segments, points, etc. are assigned unique numbers such as positions Pi, P2, etc.

When data is input into the CAD system in this manner, the approximate shape is displayed on the CRT as shown in FIG. 3b.

Next, the distance, angle, etc. from the reference for each position P1 to P8 are input for this schematic diagram. Based on the input data, the CAD system corrects the rough input figure into an accurate shape (Figure 3C).The corrected accurate figure is then sent to the CAD system by instructing it to face it. Figure 3d
By displaying a shape as shown in the figure, it is possible to understand the shape as a three-dimensional object.

Next, inputting a two-dimensional shape will be described as an example of view building blocks. As shown in FIG. 4a, a rough shape is input using line segments 2 to 3, as shown in FIG. 4b, on the screen on which the number lines are displayed. Next, the data for each position P1 to P7 is input and processed by the CAD system to obtain an accurate two-dimensional shape as shown in FIG. 4d. After this, each position P1
The arc processing is performed on P6 to P6 to obtain the shape shown in FIG. 4d.

Next, we will discuss connecting building blocks, hump building blocks, building block manipulation, and building block editing.

[Connecting building blocks]

Connecting building blocks are used for connecting partial shapes, as shown in Figure 5. This is a function that connects three-dimensional shapes directly or by defining a new solid between them. This feature consists of several commands:

(A) Obi tether (Figure 5a) A function that smoothly connects multiple strip-shaped surfaces.

(a) Direct connection (Fig. 5b) Cut off excess parts at intersection lines between multiple surfaces and connect them.

(C) Fill-in-the-blank connection (Figure 5 C) Create ruled or blended surfaces between lines.

(Work) Fillet joining (Fig. 5 d) Fillet surfaces are stretched between lines, lines and surfaces, and surfaces between surfaces, and at the same time, cut off the excess at the ends.

[Kubu building blocks]

As shown in FIG. 6, the hump blocks define a shape that is constructed additionally to the basic shape.

Specifically, it is a function to create holes, seats, joggles, and bead shapes. This feature consists of the following commands:

(A) Hole (Figure 6a) Define the hole center point and hole profile line.

(a) Seat (Fig. 6b) Create the seat shape as a three-dimensional shape. By manually adjusting the parameters of the seat center point 72, seat end 76, seat hole 70, seat slope 78, seat surface 74, and seat foot 80 that make up the seat, an integrated hump shape is created.

(C) Joggle (Figure 6C) Create a joggle shape as a solid. As a condition for defining a joggle, the surface to which the joggle is attached must be defined.

(1) Bead (Fig. 6 d) Carefully determine the bead shape. However, the bead shape is expressed as a set of intersection lines of the opposing surfaces, bead center line, and ridge lines within the bead.

[Building block operation]

The building block operation involves copying or converting a shape that has already been defined.

(a) Copy and merge the copy shape into a collection (block) of other shapes.

(B) Copy the converted figure and perform coordinate transformations such as parallel translation, rotation, enlargement, reduction, and symmetrical movement.

(C) Shape defined as a plate thickness conversion solid The shape that has been converted to plate thickness is automatically controlled.

(Engineering) Thickness direction, thickness value Set and change the three-dimensional plate thickness direction and plate thickness value.

[Building block editing]

As shown in FIG. 7, building block editing is a command group that has editing functions such as joining and dividing planes and solids.

(A) Division (Figure 7a) Splitting cuts and separates multiple lines and planes.

(b) Truncation (Figure 7b) Truncation involves cutting multiple lines and planes and deleting unnecessary parts.

(C) Extension (Figure 7C) Extension involves extending surfaces and lines.

(1) Surface division (Figure 7d) Divide one surface along a line on the surface where one end is the boundary line and the other end is within the surface.

(e) Integration of composite surfaces (Figure 7e) Multiple connected surfaces are made into a composite surface so that they can be treated as one surface.

(Force) Integration of shapes and surfaces (Fig. 7 f) Smoothly combine multiple adjacent solids into one solid. There are no touching boundaries.

(G) Vertex alignment (Fig. 7g) Compensate for distances between vertices (intersection points of multiple lines) in a three-dimensional model to eliminate gaps. Used when converting plate thickness, etc.

(h) Shape surfaceization (Figure 7h) Define a surface closed by multiple lines on the same surface. This surface is treated as a solid.

(ke) Block cutting and pasting (Fig. 7i) Connecting two solid bodies existing in different blocks,
Make it into one 3D model. Cut off the excess.

(K) Knob cutting and pasting (Fig. 7 J) In addition to the three-dimensional objects created using the Kub blocks, the three-dimensional object is connected so that it can be removed later.

(Sa) Bump separation (Fig. 7 k) Delete the three-dimensional hump shape connected as a hump and return to the basic shape.

FIG. 8 shows a flow for correcting the rough input shape as described above into an accurate shape, and the flow will be explained.

First, input the rough shape (92). Assign a unique number to each structural element of the input rough shape (94).
, input dimensions and coordinate values for each structural element of the rough shape (9
6〉. In this case, enter the direct reading dimensions. Then, the rough shapes (building blocks) of the direct dimensions are arranged in order (outline drawing - section view 11 small parts) (98).Then, the correspondence between each surface of the rough shape and the external surface is stored in the database 54 (
100). Find the cross section for each section building block and interpolate it 3
Dimensionalize (102). In this case, the lines are replaced with three-dimensional data. A surface has only surface creation information (straight line, arc direction, radius). A two-dimensional shape is determined for each view building block (104). For lines, two-dimensional data is stored in the database 54, and for surfaces, surface creation information is stored in the database 54.

Furthermore, the relationships between views and views and surfaces that are satisfied are refined (106). t also for cases where the reference data is satisfied and cases where the reference data is undefined.
ree is created (108). A refinement calculation is performed by following the tree in order (110). Refinement is performed in the same way as solving simultaneous equations. Next, we refined the small parts (11
2) , exit.

Next, the three-dimensional model creation method according to the present invention will be explained with reference to FIG. 9 in the case of dividing an automobile door.

As shown in Figure 9, using four types of building blocks: section blocks, view blocks, connecting blocks, and hump blocks, a car door is divided into several to ten or more small parts, and each small part is divided into A management name is assigned to the data and the data is managed as one three-dimensional data. When managed in this way, when there is a partial design change of a part, only a small portion of the data corresponding to the changed part needs to be corrected. In addition, data management becomes very simple.

Here, the batch statement used when defining a new shape is saved in the history file unless it is specifically deleted, and this history is saved in units of work blocks, so if you know which block you worked on, you can immediately You can search from Hidori. Therefore, in a design change in which the work procedure is the same and only parameters such as dimension values are modified, it is sufficient to simply re-execute the correction of Hiss}IJ-. Furthermore, if the parts changed due to design changes are defined as a three-dimensional shape, cutting and joining can be performed on the original shape all at once.

[Effects of the Invention] As described above, according to the present invention, it is possible to easily respond to design changes by creating a shape model by combining the three-dimensional shapes of each small part. Also,
By cutting out the part to be changed from the overall three-dimensional model, making changes to the cut-out small three-dimensional model, and combining the changed small three-dimensional model with the whole model, it is possible to easily change the part.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of the CAD system to which the present invention is applied, Figure 2 is a program diagram of the CAD system, Figure 3 is an explanatory diagram of the shape data input method, and Figure 4 is the two-dimensional shape data. An explanatory diagram of the input, Fig. 5 is an explanatory diagram of the connecting blocks in the shape obtained by the method of the present invention, Fig. 6 is an explanatory diagram of the hump blocks in the shape obtained by the method of the present invention, and Fig. 7 is an explanatory diagram of the block blocks in the shape obtained by the method of the present invention. FIG. 8 is a flowchart for refining the rough shape according to the method of the present invention. FIG. 9 is an explanatory diagram of building blocks for a car door as an example of the method of the present invention. FIG. 10 is an explanatory diagram when data is manually input into a conventional CAD system. 2...Computer 4...Mass storage device 6
...Graphic output device 8...Graphic display device 10...Tablet 12...Keyboard 14...Mouse 16...Light pen (d) (C) (C) 7 7 FIG. 6 (d) FIG. 7 (d) (i) (e) (j) (f) (k)

Claims (1)

[Claims] (1) In a method of creating a three-dimensional model using a CAD system, the final three-dimensional model is formed by dividing it into a plurality of shape parts, and the three-dimensional model is formed by joining the plurality of shape parts formed by the division. A three-dimensional model creation method characterized by the following.