JPH06348790A - Shape modeling device - Google Patents

Abstract

PURPOSE:To provide a modeling device capable of modeling the shape of an obstruction only by input to specify the obstruction. CONSTITUTION:The range of an analysis area and the number of division or the division width (three directions of x, y and z) of the area are read (S11), and a grid used in differential method analysis is generated, and the coordinate value of a grid point is obtained (S12) based on the read data. If a plotting mode is the input of a coordinate value (S13, S14), the coordinate values for three points located on a plane are read in (S15), and the equation of the plane is obtained (S16), and the coordinate value of one point located on the inside of the obstruction is read (S17). The value of the equation of the plane is decided (S18), and the coefficient of the value is inverted (S19) when it shows a positive value, and a ratio (volume ratio) of a volume through which fluid can pass in a cell, to a cell volume and an area (area ratio) through which the fluid can pass in each cell surface are obtained (S21) by a FAVOR method, then, the shape of the obstruction is plotted (S22).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a FAVOR method capable of accurately capturing the contour of an obstacle even if the contour of the obstacle crosses the inside of a cell in the numerical fluid calculation by the difference method.
(CWHirt and J.M.Sicilian, Proc.Fourth Internationa
l Conf.Ship.Hydro., National Academy of Science (198
The present invention relates to a shape modeling device that creates the shape of an obstacle based on 5)).

[0002]

2. Description of the Related Art In a conventional shape modeling apparatus in which the FAVOR method is programmed, when modeling an obstacle composed of several surfaces, the equations of the surfaces representing the respective surfaces are obtained in advance, and It is configured such that the user determines on which side the obstacle exists, the sign of each coefficient of the above equation of the surface is checked, and the sign is input to the shape modeling apparatus.

[0003]

However, when there are many obstacles to be modeled in the analysis area, the equations for each surface must be calculated individually, which is very time-consuming. There was a problem that the frequency of making mistakes also increased. Further, as a means for obtaining the equation of the surface, the coordinate values (x, y, z) of three points existing in the surface to be obtained, that is, point 1, point 2 and point 3
Then, the determinant of 4 rows and 4 columns is calculated based on this, but there is also a problem that the user who intends to perform the numerical analysis is forced to perform the calculation many times.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a shape modeling apparatus capable of modeling the shape of an obstacle only by a simple input for specifying the obstacle.

[0005]

In order to achieve the above object, a shape modeling apparatus according to the present invention has the following configuration. That is, in a shape modeling device for creating the shape of an obstacle, a reading means for reading data specifying the shape of the obstacle and a shape modeling means for modeling the shape of the obstacle based on the data read by the reading means. Have and.

[0006]

In this structure, the data for specifying the shape of the obstacle is read, and the shape of the obstacle is modeled based on the data.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail below with reference to the drawings. <First Embodiment> FIG. 1 is a schematic block diagram showing the arrangement of a shape modeling apparatus according to the first embodiment. As shown in the figure, the shape modeling apparatus 10 includes an input data reading unit 11, a grid generation unit 12, and a surface equation calculation unit 1.
3, code determination unit 14, volume ratio, area ratio calculation unit 15, obstacle contour drawing unit 16, overlay drawing determination unit 17, coefficient output unit 1
The display 20 and the key board 30 are connected to each other.

The operation of the present apparatus having the above configuration will be described below with reference to the flow chart shown in FIG. When the predetermined initialization is completed and the use of the apparatus is started, first, the input data reading unit 11 determines the range of the analysis area and the division number or division width (for three directions of x, y, z) of the area. Is read (step S11). In this reading method, data may be created in advance as a text image in the present apparatus and the data may be read, or a message prompting for data input may be output to the display 20 from the display 20. You may read it.

For example, the case of analyzing the flow of a fluid around an obstacle given in a three-sided view as shown in FIG. 3 will be described as an example, and the data shown in Table 1 may be read. .

[0010]

[Table 1]

In this case, the division width is 3.0 in all three directions of x, y and z. Next, the grid generation unit 12 generates a grid used in the difference method analysis based on the data read in step S11, creates data such as coordinate values of grid points, and holds the data (step S12). Then, the input data reading unit 11 reads and selects a drawing mode indicating whether or not a plurality of obstacle drawings to be calculated will be overwritten (step S13). In the case of this example, since there is one obstacle, the mode in which overwriting is not performed is selected.

Next, it is judged whether or not the coordinate value is inputted (step S14). If the coordinate value is inputted here, the input data reading section 11 constitutes the obstacle shown in FIG. In order to specify a surface, the coordinate values (x, y,
z) is read (step S15). At this time, x,
With respect to the plane parallel to the y and z planes, the existence region of the obstacle can be specified from the viewpoints of the lower limit and the upper limit of the three-dimensional space region. Therefore, in this example, the surface oabc is the only target in step S15. In addition, a point o, a point a, a point b, and the like are conceivable as three representative points included in the surface oabc. At this time, if the point o is processed as the coordinate origin in the three-dimensional space for convenience, the data to be read in step S15 is as shown in Table 2.

[0013]

[Table 2]

All the coordinate values shown in Table 2 can be specified from FIG. Next, the surface equation calculation unit 13 obtains a surface equation based on the coordinate values in Table 2 (step S16). Here, an algebraic equation obtained by expanding the formalized 4 × 4 surface equation by the method of Saras is prepared, and each coefficient included in this algebraic equation is obtained using the values in Table 2. You just have to do it. In the case of the example of FIG. 4, FV = −125y + 50z = 0 (1) is meant, and a result of “−125” is obtained as the coefficient of the variable y and “50” is obtained as the coefficient of the variable z, and held ( (See FIG. 5).

Then, in order to specify which side of the surface obtained in step S16 is the area where the obstacle exists,
The coordinate values of the points located inside the obstacle shown in FIGS. 3 and 4 are read from the input data reading unit 11 (step S1).
7). Here, it is necessary to previously define in the volume ratio / area ratio calculation unit 15 by the FAVOR method that the region where the FV value is negative is the obstacle existence region. For example, the data shown in Table 3 can be considered.

[0016]

[Table 3]

By substituting the values in Table 3 into the equation (1), the value of FV becomes a negative value. Therefore, the coefficient “−125” of the variable y and the coefficient “5” of the variable z obtained in step S16
The result of “0” is used as it is in step S20. In some cases, a surface equation may be obtained in the form of FV = 125y−50z = 0 (2). Coordinate value of existing point i (Table 3)
Even if is substituted, the value of FV does not become negative. Therefore, it is necessary to judge the value of the equation of the surface (step S18), and to change all the signs of the coefficients of the equation (2) of the surface if it is not negative (step S19, if (+), go to (-), If it is (-), change it to (+)).

Next, in the volume ratio / area ratio calculation unit 15, F
By the AVOR method, the ratio (volume ratio) of the fluid passable volume in the cell to the cell volume and the fluid passable area (area ratio) in each cell surface are obtained (step S21). According to this FAVOR method, even if the peripheral shape of an obstacle is positioned so as to cross the inside of the cell, the fluid simulation can be performed while recognizing the contour of the obstacle to some extent. In the difference method that does not use this method, since it is determined only by whether or not there is an obstacle in a rectangular cell or a cubic cell,
The outline of the obstacle is peeled off by a rectangular parallelepiped or a cube.

Next, the obstacle contour drawing unit 16 creates obstacle contour data from the volume ratio and the area ratio obtained in step S21, and draws the obstacle contour on the display 20 (step S22). In this example, the result is as shown in FIG. Then, in the overlap drawing determination unit 17,
It is determined whether to continue the processing (step S23), and if the processing from step S13 to step S22 is performed on another obstacle, the processing continuation is selected. In this example, since there are no other obstacles, the process proceeds to step S24.

Next, the coefficient output unit 18 writes the result as shown in FIG. 5 in the display 20 or the file and ends the processing (step S24). If this result is held, the shape modeling of FIG. 4 can be reproduced at any time by selecting "No" in step S14 and then reading this result in step S20. As described above, according to the first embodiment, when the analysis region is modeled, in the definition of the obstacle required, three points existing in each plane forming the obstacle, that is, point 1 , There is an effect that all that is required is to input the coordinate values (x, y, z) of the points 2 and 3.

<Second Embodiment> Next, a second embodiment according to the present invention will be described in detail with reference to the drawings. Even when the contour of the obstacle crosses the inside of the cell in the fluid numerical calculation by the difference method, the conventional shape modeling device programmed with the FAVOR method can accurately capture the contour of the obstacle, when the obstacle is modeled. The plane or curved surface that constitutes the obstacle is limited to be specified by a quadratic function without parentheses as shown below, and only the coefficient of each term is input.

CX2 (i) ・ x ² + CY2 (i) ・ y ² + CZ2 (i) ・ z ² + CXY (i) ・ x ・ y + CYZ (i) ・ y ・ z + CXZ (i) ・x ・ z + CX (i) ・ x + CY (i) ・ y + CZ (i) ・ z + CRXY (i) ・ √ (x ² + y ² ) + CC (i) = 0… (3) , Even if a sphere with center coordinates of (1,1,1) and radius 2 is modeled as an obstacle, (x-1) ² + (y-1) ² + (z-1) ² -4 = 0 … (4) is not allowed, and it is expanded to show x ² -2x + y ² -2y + z ² -2z-1 = 0… (5), CX2 (1) = 1.0, CX (1) =-2.0, CY2 (1) = 1.0, CY (1) =-2.0, CZ2 (1) = 1.0, CZ (1) =-2.0, CC (1) =-1.0… (6) Inputting. Where CX2 (1), CX (1), CY2
(1), CY (1), CZ2 (1), CZ2 (1) are respectively x ² , x, y ² , y, z ² , z
The coefficient of each term, CC (1), represents the constant term.

However, in the method of accepting only the input as in the equation (6), the position to be arranged for the spherical obstacle shown above is not (1,1,1) but (2,2,2). In this case, CX2 (1) = 1.0, CX (1) =-4.0, CY2 (1) to suggest x ² -4x + y ² -4y + z ² -4z + 8 = 0 (7) = 1.0, CY (1) =-4.0, CZ2 (1) = 1.0, CZ (1) =-4.0, CC (1) = 8.0… (8) It was necessary to re-input. In order to obtain the expression (7), it is necessary for the user to expand the expression "4" by replacing "1" with "2". By just trying to shift the arrangement like this, the expansion operation had to be performed based on the equations representing the spheres one by one.

The second embodiment was made in order to solve the above-mentioned problem, and in the case of a shape having a function representing the shape, the input by the shape function for specifying the shape is allowed and the specific parameter is changed. It is an object of the present invention to provide a shape modeling device that can easily reflect the above. FIG. 6 is a block diagram showing the configuration of the shape modeling apparatus according to the second embodiment. In the figure, 11 is an input data reading unit, 12 is a grid generation unit, 15 is a volume ratio and area ratio calculation unit, 16 is an obstacle contour drawing unit, 17 is an overlay drawing determination unit, 18 is a coefficient output unit, and 19 is specific. A shape function flag determination unit, 20 is a display, and 30 is a keyboard.

The operation of the present apparatus having the above configuration will be described below with reference to the flow chart shown in FIG. When the predetermined initialization is completed and the use of the apparatus is started, first, the input data reading unit 11 determines the range of the analysis area and the division number or division width (for three directions of x, y, z) of the area. Is read (step S31). In this reading method, data may be created in advance as a text image in the present apparatus and the data may be read, or a message prompting for data input may be output to the display 20 from the display 20. You may read it.

For example, as shown in FIG. 8, the case of analyzing the flow of a fluid around a sphere having a center coordinate of (1, 1, 1) and a radius of "2" will be described as an example. It would be good if you could read such data.

[0027]

[Table 4]

In this case, the division width is 3.0 in all the x, y and z directions. Next, the grid generation unit 12 generates a grid used in the difference method analysis based on the data read in step S31, creates data such as coordinate values of grid points, and holds the data (step S32). Then, the input data reading unit 11 reads and selects a drawing mode indicating whether or not a plurality of obstacle drawings to be calculated will be overwritten (step S33). In the case of this example, since there is one obstacle, the mode in which overwriting is not performed is selected.

Next, the input data reading unit 11 reads the input data representing the obstacle, and the specific shape function flag determination unit 19 determines whether or not the specific shape function flag is set (step S34). An input example at this time is as shown in FIG. FLG (i) in FIG. 9 is a flag indicating whether or not it represents a specific shape such as a sphere or a circle. When FLG (i) = 0, a general quadratic function is targeted (equation (See (3)). In FIG. 9, FLG (i)
Since ≠ 0, it indicates that a function representing a specific shape is used. The value is "2", and it is possible to identify that the equation of the sphere is used by creating a correspondence table such as Table 5 in advance (step S35).

[0030]

[Table 5]

Therefore, SPA (1), S shown in FIG.
It is recognized that the values of PB (1), SPC (1) and SPR (1) are all parameters included in the sphere equation. That is, if the general form of the sphere equation is (xa) ² + (yb) ² + (zc) ² -r ² = 0 ... (9), SPA (1), SPB (1), SPC
It is recognized that (1) and SPR (1) mean “a”, “b”, “c”, and “r” in the equation (9), respectively. By the way, in a subsequent step S38, a certain plane or a curved surface is used as a boundary to determine which side of the obstacle actually exists, and the area through which the fluid can pass is calculated. In the calculation here, it is preferable to use a general equation such as Equation (3) rather than preparing many kinds of equations such as a plane equation and a sphere equation to be used. It is more efficient to prepare only one and process it.

Therefore, in step S36, coefficient conversion between the equations (3) and (9) is automatically performed. In the case of the present example, it is known that the parameter is given by using the sphere equation (FIG. 9), and therefore the conversion shown in FIG. 10 may be executed. Next, in the volume ratio / area ratio calculation unit 15, the ratio (volume ratio) of the fluid permeable volume in the cell to the cell volume and the fluid permeable area (area percentage) in each cell surface are calculated by the FAVOR method. Is calculated (step S38). According to this FAVOR method, even if the peripheral shape of an obstacle is positioned so as to cross the inside of the cell, the fluid simulation can be performed while recognizing the contour of the obstacle to some extent. In the difference method that does not use this method, since the judgment is made only by whether or not there is an obstacle in a rectangular or cubic cell, the outline of the obstacle is stripped off by the rectangular or cubic shape.

Next, the obstacle contour drawing unit 16 creates obstacle contour data from the volume ratio and the area ratio obtained in step S38, and draws the obstacle contour on the display 20 (step S39). Then, the overlapping drawing determination unit 17
Then, it is determined whether or not the processing is to be continued (step S40), and when the processing from step S33 to step S39 is performed on another obstacle, the processing continuation is selected. In this example,
Since there are no other obstacles, the process proceeds to step S41.

Next, the coefficient output unit 18 writes the result as shown in FIG. Now, when confirming the obstacle drawn on the display 20, he notices that the arrangement position is incorrect, and the arrangement position is changed from (1, 1, 1) to (2,
In the case of changing to 2, 2), it is immediately apparent from general knowledge of mathematics that a, b, c in the equation (9) should be changed from "1" to "2". That is, in the case of this example, the values of SPA (1), SPB (1), and SPC (1) shown in FIG. 9 are changed from “1” to “2” (see FIG. 12), and from step S31. Just re-run.

As described above, according to the second embodiment, in a shape such as a sphere or a cylinder having a function representing the shape, it is desired to allow the input by the shape function for specifying the shape and to arrange the shape. It is possible to easily reflect a specific parameter change such as the position or radius. The present invention is
It may be applied to a system composed of a plurality of devices or an apparatus composed of one device.

Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0037]

As described above, according to the present invention, the shape of an obstacle can be modeled by only a simple input for specifying the obstacle.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a shape modeling apparatus according to a first embodiment.

FIG. 2 is a flowchart showing an operation procedure in the first embodiment.

FIG. 3 is a triangular diagram showing dimensions of an obstacle in the first embodiment.

FIG. 4 is a sketch of an obstacle in the first embodiment.

FIG. 5 is a diagram showing a result displayed on a display in the first embodiment.

FIG. 6 is a block diagram showing a configuration of a shape modeling apparatus according to a second embodiment.

FIG. 7 is a flowchart showing an operation procedure in the second embodiment.

FIG. 8 is a sketch drawing of an obstacle in the second embodiment.

FIG. 9 is input data representing an obstacle in the second embodiment.

FIG. 10 is a diagram showing coefficient conversion in the second embodiment.

FIG. 11 is a diagram showing a result displayed on a display in the second embodiment.

FIG. 12 is input data when changing the arrangement of obstacles in the second embodiment.

[Explanation of symbols]

 10 Shape Modeling Device 11 Input Data Reading Unit 12 Lattice Generation Unit 13 Surface Equation Calculation Unit 14 Code Determination Unit 15 Volume Ratio and Area Ratio Calculation Unit 16 Obstacle Contour Drawing Unit 17 Overwrite Determination Unit 18 Coefficient Output Unit 19 Specific Shape Function Flag determination unit 20 Display 30 Key board

Claims (2)

[Claims] 1. A shape modeling apparatus for creating the shape of an obstacle, wherein the shape of the obstacle is modeled based on the reading means for reading the data for specifying the shape of the obstacle and the data read by the reading means. A shape modeling device, comprising: shape modeling means. 2. The shape modeling apparatus according to claim 1, wherein the reading means inputs a shape function for specifying the shape according to the shape of the obstacle.