JP6334347B2 - Interpolation plane generation method - Google Patents

Description

  The present invention relates to an interpolation plane generation method.

  Panel products such as outer panels and roof panels for automobiles are manufactured by pressing a single plate with a mold that has a desired product shape to form a press-molded product. Is formed by forming a flange portion or making a hole through which a bolt is inserted. In such a panel product, a production line is designed before a production process for actual production.

  Specifically, when the design design of the product shape is performed, a draw model of a press-formed product is generated from this design design, and the model shape is evaluated by CAE (Computer Aided Engineering), so that the designed shape is actually It is decided to check whether it can be pressed.

Here, the relationship between the product shape and the draw model will be described with reference to FIG. The draw model 9 includes a product portion 91 designed for a vehicle type, a surplus portion 93 that is assumed to be cut off, and a die face portion 95 that is assumed to be pressed when pressed with a mold. Consists of.
Since the product shape is obtained when the design design is made, the product portion 91 of the draw model 9 can be generated together with the design design. The die face portion 95 is basically a flat surface because it is assumed to be a heel presser, and can be generated relatively easily. On the other hand, since the surplus portion 93 is a portion that deforms in accordance with the press work, it takes much time to generate the surplus portion 93 in the generation of the draw model 9.

  Further, when the model shape evaluation by CAE is not good, it is necessary to repeat the correction of the surplus portion and the analysis by CAE, which takes a huge amount of time. Therefore, in recent years, a model design system is known that can design a draw model whose quality is guaranteed by CAE in a short time by selecting a cross section of the surplus portion from a predetermined template (Patent Document 1).

JP 2009-104456 A

  According to the model design system of Patent Document 1, although it is possible to easily set the cross section of the surplus portion, it still takes enormous time to generate the surface data from the setting of the cross section.

  Therefore, the applicant has proposed a draw model generation system that sets a parent cross section for the surplus portion, generates a child cross section based on the parent cross section, and generates an interpolation plane using the parent cross section and the child cross section. ing. According to this draw model generation system, polygon data of the surplus portion can be automatically obtained from the parent cross section and child cross section set in the surplus portion, and surface data can be stably generated in a short time. it can.

  However, this draw model generation system has not been sufficiently studied for application to various shapes. For this reason, depending on the shape, no consideration is given to the fact that the child cross-sections may intersect each other when generating the child cross-sections, and in this case, the generation of the interpolation plane may fail.

  The present invention has been made in view of the above, and an object of the present invention is to provide an interpolation surface generation method capable of stably generating an interpolation surface by avoiding crossing of child cross sections generated based on a parent cross section. And

(1) In order to achieve the above object, the present invention is an interpolation surface generation method for generating, by a computer, an interpolation surface for interpolating between a reference line defined in a three-dimensional space and an opposite shore line facing the reference line. A parent cross section setting step for setting a plurality of parent cross sections parallel to the Z axis between the reference line and the opposite bank line, and a pair of adjacent parent cross sections among the plurality of parent cross sections. The interpolated surface is generated so as to include a child cross-section generating step for generating one or more child cross-sections parallel to the Z axis, and a surface defined based on the plurality of parent cross-sections and the plurality of child cross-sections. An interpolation plane generation step, wherein an angle formed between the child cross section and the reference line is different from an angle formed between another child cross section adjacent to the child cross section or the parent cross section and the reference line. An interpolation plane generation method is provided.

  (2) In this case, in the child section generation step, an angle formed by one parent section and the reference line is set as a first parent angle, and an angle formed by the other parent section and the reference line is set as a second parent section. It is preferable to determine an angle between the child cross section between the pair of parent cross sections and the reference line based on the first and second parent angles.

  (3) In this case, in the child section generation step, an angle formed by the plurality of child sections between the pair of parent sections and the reference line is between the first parent angle and the second parent angle. And in order from the child cross section on the one parent cross section side toward the child cross section on the other parent cross section side, the angle close to the second parent angle is changed from the angle close to the first parent angle. It is preferable to change it.

  (4) In this case, the child cross section generation step includes a step of setting a start point at a predetermined position on the reference line between the pair of the parent cross sections, and one parent cross section of the pair and the reference A step of calculating a ratio between a distance between an intersection of a line and the start point and a distance between an intersection with the reference line of the pair of parent sections, and the one parent section and the reference line; A step of setting a start point angle with respect to the start point based on an angle, an angle formed by the other parent cross section and the reference line, and a ratio calculated with respect to the start point; and the calculated A step of setting an end point corresponding to the start point on the opposite shore line at the same ratio as the ratio, an angle formed by the one parent cross section and the opposite shore line, and an angle formed by the other parent cross section and the opposite shore line; And setting an end point angle with respect to the end point based on the calculated ratio. A step, the reference lines and intersect at the opposite bank lines and each of the start angle and the end point angle, and generating a child section to include the start point and the end point, it is preferable to include a.

(5) In order to achieve the above object, the present invention is an interpolation surface generation method for generating, by a computer, an interpolation surface that interpolates between a reference line defined in a three-dimensional space and an opposite shore line facing the reference line. there are a parent section setting step of setting a plurality of parent section parallel to the Z axis between the opposite bank line and the reference line, Z between a pair of the parent section adjacent the plurality of parent section An interpolating surface for generating the interpolating surface so as to include a sub cross section generating step for generating one or more sub cross sections parallel to the axis, and a surface defined based on the plurality of parent cross sections and the plurality of child cross sections. Generating step, wherein the child cross-section generating step is a step of setting a start point at a predetermined position on the reference line between the pair of parent cross-sections, and one parent cross-section of the pair and the The distance between the intersection of the reference line and the start point, and the parent cross-section pair A step of calculating a ratio with a distance between intersections with the quasi-line, a step of setting an end point corresponding to the start point on the opposite bank at the same ratio as the calculated ratio, and the reference line and the opposite bank And generating a child cross-section that intersects with and includes the start point and the end point.

  In the interpolation plane generation method of (1), the child cross section is formed such that the angle formed between the child cross section and the reference line is different from the angle formed between the other child cross section adjacent to the child cross section or the parent cross section and the reference line. Generate. According to the present invention, since the child cross section is generated by changing the angle formed between the child cross section and the reference line, it is possible to avoid the crossing of the child cross sections and to stably generate the interpolation plane.

  In the interpolation plane generation method (2), an angle formed by one parent cross section and a reference line is a first parent angle, and an angle formed by the other parent cross section and a reference line is a second parent angle. Based on the first and second parent angles, the angle between the child cross section between the parent cross section pair and the reference line is determined. According to the present invention, since the angle formed between the child cross section and the reference line is determined based on the angle formed between the reference line of the paired parent cross section, the crossing of the parent cross section and the child cross section can be avoided and stably performed. Interpolation plane can be generated.

  In the interpolation surface generation method (3), an angle formed by a plurality of child cross sections between a pair of parent cross sections and a reference line is determined between the first parent angle and the second parent angle. At the same time, in order from the child cross section on the one parent cross section side toward the child cross section on the other parent cross section side, the angle is changed from the angle close to the first parent angle to the angle close to the second parent angle. According to the present invention, the angle formed between the child cross section and the reference line increases from the first parent angle of one parent cross section to the second of the other parent cross section as it goes from one parent cross section side to the other parent cross section side. Therefore, it is possible to reliably avoid the crossing of the parent cross section and the child cross section, and to stably generate the interpolation plane.

  In the interpolation plane generation method (4), the starting point is set on each reference line, the ratio of the distance of the starting point to the parent cross-section pair is calculated, and the starting point angle is calculated based on this ratio. On the other hand, the end point is set on the opposite shore line at the same ratio as the ratio calculated at the start point, and the end point angle is calculated based on this ratio. Then, the child cross section is generated so as to intersect the reference line and the opposite bank line at the start point angle and the end point angle and to include the start point and the end point. Thereby, it is possible to stably generate the interpolation plane while avoiding the crossing of the parent cross section and the child cross section. In this method, a child cross section is generated based on the start point and end point angles and the start point and end point angles associated with the start point and end point. For this reason, this method is suitable for generating an interpolation surface having a complicated solid shape whose parent cross section is not a plane, for example.

  The interpolation plane generation method of (5) sets the start point on the reference line, and calculates the ratio of the distance between one parent cross section and the start point and the distance between one parent cross section and the other parent cross section. The end point is set on the opposite bank at the same ratio as that calculated on the reference line side, and the child cross section is generated so as to include the start point and the end point. Thereby, it is possible to stably generate the interpolation plane while avoiding the crossing of the parent cross section and the child cross section. In addition, since this method does not include an angle calculation as compared with the method (1), for example, it is possible to stably avoid the intersection of the parent cross section and the child cross section with a simple calculation.

It is a figure which shows the outline | summary of the draw model production | generation system which concerns on 1st Embodiment of this invention. It is a block diagram which shows the function structure of a draw model production | generation system. It is a figure which shows an example of the plane grating | lattice which has a some feature point. It is a figure which shows an example of the master cross section set between a product part and a die face part. It is a figure which shows an example of the child cross section produced | generated from a parent cross section. It is the figure which planarly viewed the area | region which produces | generates a some child cross section along a Z-axis direction. It is a flowchart which shows the procedure which sets a child reference point, a child opposite bank point, and a child reference angle based on a pair of selected parent cross section. It is a figure which shows an example of the map which determines a child reference | standard angle. It is a figure which shows an example of the grandchild reference point set between selection reference points. It is a flowchart which shows the procedure of a re-division process. It is a figure which shows an example of the calculation method of the Z coordinate of the projected feature point. It is a figure which shows an example of the calculation method of the Z coordinate of the feature point projected on the surplus part. It is a figure which shows an example of the calculation method of the Z coordinate of the feature point projected on the surplus part. It is a figure which shows typically the N area | region distributed with respect to N computers. It is a figure which shows an example of the calculation method of the Z coordinate of the feature point projected on the product part. It is a flowchart which shows the flow of a process of a draw model production | generation system. It is a flowchart which shows the flow of a process of a draw model production | generation system. It is a flowchart which shows the flow of a process of a draw model production | generation system. It is a figure which shows the definition of a sag value. It is a figure which shows an example of the draw model which consists of a product part, a surplus part, and a die face part. It is a flowchart which shows the specific procedure which sets the child cross section which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the specific procedure which sets a child cross section in case a parent cross section is planar. It is the figure which planarly viewed the child cross section produced | generated between a pair of planar parent cross sections along the Z-axis. It is a flowchart which shows the specific procedure which sets the child cross section in case a parent cross section is non-planar. It is the figure which planarly viewed the child cross section produced | generated between a pair of non-planar parent cross sections along the Z-axis. It is a figure which shows an example of the map which determines a child reference | standard angle.

[First Embodiment]
Hereinafter, a draw model generation system to which an interpolation plane generation method according to a first embodiment of the present invention is applied will be described with reference to the drawings.

[Outline of draw model generation system]
First, the outline of the draw model generation system of the present invention will be described with reference to FIG. In the draw model generation system, a draw model 9 of a press-formed product is generated from a product part 91 and a die face part 95 generated using CAD (Computer Aided Design). Specifically, in the draw model generation system, as shown in FIG. 1B, each of the regions corresponding to the draw model 9 including the product portion 91 and the die face portion 95 is defined by individual XY coordinates. A planar grid 10 composed of a plurality of feature points 101 is projected. Then, as shown in FIG. 1C, the projected feature points 101 are connected to form a polygon 102, thereby generating a draw model 9.

At this time, as shown in FIG. 1A, since the shape of the product part 91 and the die face part 95 is defined in advance, the coordinates of the feature point 101 projected onto the product part 91 and the die face part 95 (Z (Coordinates) can be easily obtained. On the other hand, since the shape of the surplus portion 93 is not defined, the coordinates (Z coordinate) of the feature point 101 projected onto the surplus portion 93 cannot be acquired.
In this regard, in the draw model generation system of the present invention, the draw model 9 is generated by interpolating the coordinates (Z coordinate) of the feature point 101 projected on the surplus portion 93 by a method described later and generating an interpolation plane. I am going to do that.

  In the following, the contour line of the product part 91 is referred to as a reference line BL, and the contour line of the die face part 95 facing the reference line BL is referred to as a counter bank OL. In general, since the reference line BL and the opposite bank line OL are closed curves, the surface shape of the surplus portion 93 can be specified by a plurality of cross-sectional lines connecting the lines BL and OL. As described above, since the shapes of the product portion 91 and the die face portion 95 are defined by fine CAD data, the three-dimensional shapes of the reference line BL and the opposite bank line OL can be obtained from these CAD data. it can.

[Draw model generation system configuration]
Then, with reference to FIG. 2, the structure of the draw model production | generation system 1 of this invention is demonstrated. FIG. 2 is a block diagram showing a functional configuration of the draw model generation system 1 according to the first embodiment of the present invention.
The draw model generation system 1 includes an input device 2 through which an operator inputs various data and commands, an arithmetic device 4 that executes various arithmetic processes according to inputs from the input device 2, and a display device 6 that displays an image. And a storage device 8 that stores various data, and a parallel computer PCC that can communicate with the main computer PC0.

  The input device 2 includes hardware such as a keyboard and a mouse that can be operated by an operator. Data and commands input by operating the input device 2 are input to the arithmetic device 4.

  The display device 6 is configured by hardware such as a CRT or a liquid crystal display capable of displaying an image. For example, a three-dimensional image of a draw model is displayed on the display unit of the display device 6 as a processing result by the arithmetic device 4.

  The storage device 8 is configured by hardware such as a hard disk drive or a solid state drive, and stores CAD data including shape data of the product part 91 and shape data of the die face part 95 generated using CAD. The CAD data stored in the storage device 8 does not include the shape data of the surplus portion 93. Further, the storage device 8 stores plane grid data including data (XY coordinates) of feature points 101 constituting the plane grid 10. The storage device 8 also stores cross-sectional data including parameters that define the cross-sectional shape set in the surplus portion 93 or the like.

  The arithmetic device 4 is configured by hardware such as a CPU, and in cooperation with predetermined software, the plane lattice generation unit 41, the parent cross section setting unit 42, the child cross section generation unit 43, the coordinate calculation unit 44, the draw A model generation unit 45 and a parallel calculation management unit 49 are included.

  The parallel computer PCC is composed of N computers (N is an integer of 2 or more) PC1, PC2,... PCN. Each of the computers PC1, PC2,... PCN is provided with an arithmetic device having at least the same function as the child section generating unit 43 of the main computer PC0. Further, each of the computers PC1, PC2,... PCN includes an independent storage device for storing later-described partial CAD data transmitted from the main computer PC0. Therefore, each of the computers PC1, PC2,... PCN reads the partial CAD data stored in the individual storage devices as appropriate, so that it becomes independent without transmitting / receiving large-capacity CAD data to / from other computers. Arithmetic can be performed.

  Returning to the description of the function of the arithmetic unit 4 of the main computer PC0, the plane grid generator 41 generates the plane grid 10 shown in FIG. 3 in response to a command from the operator via the input device 2. The planar lattice 10 generated by the planar lattice generation unit 41 is stored in the storage device 8. The plane grid 10 may be stored in advance in the storage device 8 and read out from the storage device 8 as necessary, instead of being generated according to the operation of the operator.

Here, the planar grating 10 will be described with reference to FIG. As shown in FIG. 3A, the planar grid 10 is configured by arranging a plurality of feature points 101, each defined by individual XY coordinates, in a grid at predetermined intervals.
Although the interval between the feature points 101 is arbitrary, the optimum interval Dopt can be determined by conducting an experiment in accordance with the target panel product in consideration of the balance between calculation load and accuracy. A procedure for determining such an optimal interval Dopt will be specifically described with reference to FIGS. FIG. 3B is a schematic diagram showing a cross-sectional shape of the product portion 91, and FIG. 3C is a portion where the polygonal bending angle is the largest among panel products such as an outer panel and a roof panel of an automobile. It is a figure which shows the relationship between the space | interval of the feature point 101 in FIG.

As described above, in the draw model generation system 1 of the present invention, the plane grid 10 (feature point 101) is projected onto the product unit 91 and the like, and the Z coordinate of the feature point 101 is acquired. Here, the interval between the feature points 101 projected on the product part 91 varies depending on the inclination of the product part 91 with respect to the XY coordinates.
With reference to FIG. 3 (B), the product part 91 considers the cross-sectional shape comprised from the planes 911 and 913 substantially parallel to XY coordinate, and the inclined surface 912 inclined by predetermined angle with respect to XY coordinate. At this time, when the interval L1 between the feature points 101 projected onto the planes 911 and 913 is compared with the interval L2 between the feature points 101 projected onto the slope 912, the interval L2 becomes wider. The interval between the feature points 101 is a bending angle of the polygon 102 when the polygon 102 is acquired by connecting the feature points 101. If the bending angle of the polygon 102 is large, it causes an error in the model shape evaluation by CAE, so it is necessary to keep it within a range where no error occurs.
As shown in FIG. 3C, in the model shape evaluation by CAE, if the bending angle of the polygon 102 exceeds a predetermined allowable value θmax, there is a problem such as an error or an incorrect solution. In this regard, in an automobile panel product, the polygon 102 has a bending angle of about θmax by setting the interval between the feature points 101 to Dmax. In such a case, the optimum interval Dopt of the feature point 101 is less than the maximum allowable interval Dmax corresponding to the allowable value θmax. It is set to a value obtained by subtracting a margin of about several mm. As described above, the optimum interval Dopt of the feature point 101 can be determined for the target panel product. Note that θmax is an empirical threshold and is different for each CAE software.

  Returning to FIG. 2, the parent cross-section setting unit 42 sets the Z-axis between the reference line BL and the opposite bank line OL (that is, the surplus portion 93) in response to a command from the operator via the input device 2. A plurality of parallel cross sections (hereinafter, the cross section set by the parent cross section setting unit 42 is referred to as “parent cross section”) is set. The plurality of parent cross sections set by the parent cross section setting unit 42 are stored in the storage device 8 in association with parameters that define the shape of the cross section. In addition, the setting method of the parent cross section is arbitrary, for example, it may be manually set by an operator, or may be set using a preset cross-sectional template as in Patent Document 1 described above. Good.

Here, with reference to FIG. 4, the parent cross section set in the surplus portion 93 will be described. As shown in FIG. 4A, the parent cross section setting unit 42 includes a plurality of parent cross sections 931A, 931B, and 931C in the surplus portion 93 between the product portion 91 and the die face portion 95 where the shape data is generated. (Hereinafter collectively referred to as “parent cross section 931”).
As shown in FIG. 4B, the parent cross section 931 is configured by a cross section line that connects a predetermined reference point BP of the reference line BL to a predetermined counter point OP of the counter bank OL. The cross-sectional line is formed by connecting a plurality of straight lines and a plurality of curved lines, and is defined by a plurality of parameters indicating specific shapes of the straight lines and the curved lines. The parameters that define the parent cross section 931 can include necessary information as appropriate, but at least include information capable of calculating XYZ coordinates at an arbitrary position on the parent cross section 931. In the present embodiment, as these parameters, parameters L1, L2, L3, L4 (mm) indicating the length of each straight line, parameters R1, R2, R3 (mm) indicating the curvature radius of each curve, and each curve Parameters A1, A2, A3 (deg) indicating the wall angle, and the start position (the position of the reference point BP on the reference line BL) and the end position (the position of the opposite shore point OP on the opposite shore line OL) of the parent section 931 are shown. XYZ coordinates and an angle θ (deg) formed by the parent cross section 931 and the reference line BL are included. Further, as shown in FIG. 4A, the parent cross-section setting unit 42 has a plurality of parent cross-sections 931A, 931B, and 931C while separating the reference point BP and the opposite shore point OP by a predetermined distance so as not to cross each other. Set. In the following, the reference point BL and the opposite bank point OP of the parent section 931 are referred to as a parent reference point BP and the parent opposite point OP, and the angle θ formed by the parent section 931 and the reference line BL is referred to as a parent reference angle θ.

  Returning to FIG. 2, the child cross-section generating unit 43 includes a plurality of cross-sections parallel to the Z-axis (hereinafter referred to as child cross-sections) between pairs of adjacent parent cross-sections among the plurality of parent cross-sections 931, similar to the parent cross-section. The section generated by the generation unit 43 is referred to as a “child section”). As described above, the reference line BL and the opposite bank line OL are respectively closed curves, and the parent cross sections are set with a space between the reference point BP and the opposite bank point OP so as not to cross each other. Therefore, when a pair of two parent cross sections adjacent to each other is set, a closed curve is formed with the pair of the parent cross section, the reference line, and the opposite shore line as sides. The child cross-section generating unit 43 generates a plurality of child cross-sections that do not cross each other in the closed curve formed by these parent cross-sections based on the shapes of these parent cross-sections. Such generation of a plurality of child cross sections can be realized by a normal function in publicly known parametric CAD software. Hereinafter, a specific procedure for generating a plurality of child cross sections will be described.

  As shown in FIG. 5A, the surplus portion 93 between the reference line BL defined in the product portion 91 and the opposite bank line OL defined in the die face portion 95 has a plurality of parent cross sections 931A and 931B. Is set. In the example of FIG. 5, it is assumed that the parent cross section 931 has a one-stage cross-sectional shape, and the parent cross section 931B has a two-stage cross-sectional shape.

  These parent cross sections 931A and 931B are set with a predetermined interval as shown in FIG. 5B in accordance with a command from the operator. The child cross-section generating unit 43 fills a space between the parent cross sections 931A and 931B by generating a plurality of child cross sections having shapes similar to the parent cross sections 931A and 931B between the parent cross sections 931A and 931B. At this time, the child cross section generation unit 43 generates two types of child cross sections, a child cross section based on the parent cross section 931A and a child cross section based on the parent cross section 931B.

  Specifically, the child cross-section generating unit 43 divides a section between the parent reference points BP1 and BP2 of the parent cross-sections 931A and 931B in the reference line BL at a predetermined pitch, thereby obtaining each child cross-section. The child reference points BPC1, BPC2, BPC3, BPC4 corresponding to the start point and the child opposite points OPC1, OPC2, OPC3, OPC4 corresponding to the end point are set (see FIG. 5C). Next, the child section generation unit 43 sets child reference angles θC1, θC2, θC3, and θC4 corresponding to the angles formed by the child sections and the reference line BL for each child reference point BPC1... BPC4 (FIG. 5 ( D)). A specific procedure for setting the child reference point BPC1... BPC4, the child opposite bank point OPC1... OPC4, and the child reference angle θC1. This will be described with reference to FIGS.

  Next, as shown in FIG. 5C, the child cross section generator 43 has a plurality of child cross sections 933A having a shape similar to one of the parent cross sections 931A and intersecting with the reference line BL at child reference angles θC1. 933B, 933C, and 933D (hereinafter collectively referred to as “child section group 933”) are generated between the child reference points BPC1... BPC4 and the child opposite shore points OPC1. Here, the child cross-section generating unit 43 uses the above-described child reference angles θC1... ΘC4, child reference points BPC1... BPC4, and child counterpoints OPC1. By using a known algorithm under conditions, a child section group 933 having a shape similar to the parent section 931A is generated.

  Next, as shown in FIG. 5E, the child cross section generator 43 has a plurality of child cross sections 935A having a shape similar to that of the other parent cross section 931B and intersecting with the reference line BL at child reference angles θC1. 935B, 935C, and 935D (hereinafter collectively referred to as “child section group 935”) are generated between the child reference points BPC1... BPC4 and the child opposite shore points OPC1. Here, the child cross-section generating unit 43 uses the child reference angles θC1... ΘC4, the child reference points BPC1... BPC4, and the child counterpoints OPC1. By using a known algorithm under conditions, a child cross section group 935 having a shape similar to the parent cross section 931B is generated.

  Next, a specific procedure for setting the child reference point, the child opposite shore point, and the child reference angle so that the child cross section does not intersect with other child cross sections or the parent cross section will be described with reference to FIGS. To do.

  FIG. 6 is a plan view of a region where a plurality of child cross-sections are generated along the Z-axis direction. Here, the area | region which produces | generates a child cross section is an area | region enclosed with a pair of adjacent parent | cross sections 931A and 931B, the reference line BL, and the opposite bank line OL, as shown in FIG. Note that, as described above, the parent cross section and the child cross section are set in a plane parallel to the Z axis, and these cross sections are straight when viewed in plan as shown in FIG. The child cross-section generating unit 43 and the plurality of child reference points BPC1, BPC2,..., And the plurality of child counter-bank points OPC1, OPC2,. And a plurality of child reference angles θC1, θC2,...

FIG. 7 is a flowchart showing a specific procedure for setting a child reference point, a child opposite bank point, and a child reference angle based on a selected pair of parent cross sections.
First, in step S51, the child section generation unit 43 acquires three-dimensional coordinate information of the selected parent sections 931A and 931B, the reference line BL, and the opposite bank line OL, and based on this information, the parent reference point BP1, BP2 and parent opposite shore points OP1 and OP2 and parent reference angles θ1 and θ2 are calculated (see FIG. 6).

  In step S52, the child cross-section generating unit 43 determines values of an initial pitch Pdef (mm), a pitch upper limit Pmax (mm), and a pitch lower limit Pmin (mm) that are setting parameters used in the following processing. Values set by the operator may be used as the values of the setting parameters Pdef, Pmax, and Pmin, or predetermined values may be used. The upper limit of the pitch corresponds to the upper limit of the interval between adjacent child reference points or child opposite shore points, and is, for example, 8 mm. In the following processing, the interval between the child reference point or the child opposite shore point is set so as not to exceed this pitch upper limit as much as possible. The pitch lower limit corresponds to the lower limit of the interval between adjacent child reference points or child opposite shore points, and is, for example, 0.1 mm. In the following processing, the interval between the child reference point or the child opposite shore point is set so as not to fall below this pitch lower limit as much as possible. The initial pitch corresponds to the initial interval between the two child reference points, and is, for example, 5 mm.

  In step S53, the child cross-section generating unit 43 starts from the parent reference point (parent reference point BP1 of the parent cross-section 931A in the example of FIG. 6) of the parent cross-section with the larger reference angle from the start point to the other reference point. To the parent reference point (parent reference point BP2 of the parent section 931B in the example of FIG. 6), n child reference points BPC1, BPC2,..., BPCn are set on the reference line BL for each initial pitch Pdef. Set.

  In step S54, the child cross-section generating unit 43 sets child reference angles θC1... ΘCn corresponding to the child reference points BPC1... BPCn based on the two parent reference angles θ1 and θ2. More specifically, the child section generation unit 43 determines each child reference angle θC1... ΘCn between the parent reference angles θ1 and θ2, and close to the parent reference angle θ2 from an angle close to the parent reference angle θ1. Change to an angle. That is, θ1> θC1>...> ΘCn> θ2. Thus, different angles can be assigned so that the child cross sections set at the child reference points BPC1... BPCn do not intersect with other child cross sections or the parent cross section.

Such child reference angle allocation can be realized by constructing a map as shown in FIG. 8 based on the two parent reference angles θ1 and θ2.
As shown in FIG. 8, two points that specify two parent reference points BP1 and BP2 in a two-dimensional coordinate system in which the vertical axis is a reference angle (deg) and the horizontal axis is a distance (mm) along the reference line. By plotting and interpolating these two points with a straight line or a smooth curve, a map for uniquely identifying the distance from the parent reference point BP1 and the reference angle at that point can be constructed.

  Returning to FIG. 7, in step S54, the child cross-section generating unit 43 sets child reference angles θC1... ΘCn for each child reference point BPC1.

  In step S55, the child cross-section generating unit 43 sets child opposite shore points OPC1... OPCn for each child reference point BPC1... BPCn based on the child reference angles θC1. As described above, the child cross section is set parallel to the plane including the Z axis. Accordingly, the child opposite point OPC1... OPCn with respect to each child reference point BPC1... BPCn is not subjected to the calculation of the detailed shape of the child cross section, and the straight line and the opposite bank extending from these child reference points BPC1. It can be easily calculated as an intersection with the line OL (see FIG. 6).

  By executing the processing of S51 to S55, n + 2 reference points BP1, BPC1,..., BPCn, BP2 and n + 2 corresponding to these reference points are selected for the two selected parent cross sections 931A, 931B. , OPCn, OP2 and n + 2 reference angles θ1, θC1,..., ΘCn, θ2 are set (see FIG. 6). The subsequent processing of S56 to S58 is processing for newly generating a reference point between the reference points as necessary under the pitch upper limit Pmax and the pitch lower limit Pmin determined in S52.

  In step S56, the child cross-section generating unit 43 selects two reference points adjacent to each other among the n + 2 reference points. In the following, the set of reference points selected here will be referred to as selection reference points BS1 and BS2. Further, the opposite shore points and reference angles corresponding to these selected reference points BS1 and BS2 are set as selected opposite shore points OS1 and OS2 and selected reference angles θS1 and θS2, respectively (see FIG. 9). Further, θS1> θS2.

  In step S57, the child cross-section generating unit 43 performs re-division processing (see FIG. 10 described later) on the set of selection reference points BS1 and BS2 selected in step S56, thereby selecting the selection reference points BS1 and BS2. M grandchild reference points (m is an integer of 0 or more), which are numbers determined as necessary, are generated during BS2.

  FIG. 10 is a flowchart showing a specific procedure of the re-division processing. In this subdivision process, it is determined whether or not it is necessary to further divide the reference points BS1 and BS2 between a pair of selection reference points BS1 and BS2 adjacent to each other. In this case, it is a process of newly generating one grandchild reference point BPD between these reference points BS1 and BS2. When one grandchild reference point BPD is generated between the two reference points BS1 and BS2, two sets of adjacent reference points are generated. Therefore, when one grandchild reference point BPD is newly generated, it is necessary to perform further subdivision processing on these two sets of selected reference points (a set of reference points BS1 and BPD and a set of reference points BPD and BS2). There is. For this reason, the subdivision process of FIG. 10 is a recursive algorithm including two processes (see S70 and S72) that are the same as the self.

  In step S61, the child cross-section generating unit 43 calculates the distance D1 between the selection reference points BS1 and BS2 and the distance D2 between the selected opposite shore points OS1 and OS2 corresponding to these selection reference points (see FIG. 9).

  In steps S62 and S63, the child cross-section generating unit 43 determines whether or not the division is necessary based on the calculated distances D1 and D2 between the reference points. More specifically, in step S62, the child cross-section generating unit 43 determines whether any of the reference point distance D1 or the opposite shore point distance D2 is smaller than the pitch lower limit Dmin. In step S63, the child cross-section generating unit 43 determines whether both the reference point distance D1 and the counterpoint distance D2 are smaller than the pitch upper limit Dmax. If both of these steps S62 and S63 are NO, the child cross-section generating unit 43 proceeds to step S64 and determines that the selection reference points BS1 and BS2 need to be further divided. Further, if any of these steps S62 and S63 is YES, the child cross-section generating unit 43 determines that the division is not necessary (see step S65), and immediately ends this process.

  In steps S66 to S68, the child cross-section generating unit 43 divides the selection reference points BS1 and BS2. More specifically, in step S66, the child cross section generation unit 43 sets the grandchild reference point BPD at the center position of these reference points BS1 and BS2 on the reference line BL for the selection reference points BS1 and BS2. In step S67, the child cross-section generating unit 43 sets the grandchild reference angle θD for the set grandchild reference point BPD according to the same procedure as in step S54. That is, a grandchild reference angle θD that satisfies θS1> θD> θS2 is set using a map as shown in FIG. In step S68, the child cross-section generating unit 43 sets a grandchild opposite bank point OPD corresponding to the grandchild reference point BPD according to the same procedure as in step S55.

  In step S69, the child cross-section generating unit 43 selects two reference points adjacent to each other among the three reference points BS1, BPD, BS2. Here, two reference points BS1 and BPD having a relatively large reference angle are set as selection reference points. In step S70, the child cross-section generation unit 43 performs re-division processing on the set of selection reference points BS1 and BPD selected in step S69, so that the selection cross-section points BS1 and BPD can be used as necessary. N grandchild reference points (n is an integer equal to or greater than 0), which are predetermined numbers, are generated.

  In step S72, the child cross-section generating unit 43 selects two reference points adjacent to each other among the three reference points BS1, BPD, BS2. Here, two reference points BPD and BS2 having a relatively small reference angle are set as selection reference points. In step S73, the child cross-section generating unit 43 performs a re-division process on the set of selection reference points BPD and BS2 selected in step S72, so that the selection cross-section points BPD and BS2 can be used as necessary. The number of grandchild reference points (l is an integer of 0 or more), which is a predetermined number, is generated.

  Returning to FIG. 7, in step S <b> 58, the child cross-section generating unit 43 determines whether or not the re-division process of S <b> 57 has been executed for all combinations. If the determination in step S58 is NO, the process proceeds to step S57 to select another reference point combination. If the determination is YES, this process ends. By performing the above processing, the child section generation unit 43 can set the child sections that are dense enough to be within the range specified by the pitch upper limit Pmax and the pitch lower limit Pmin so as not to cross each other. . In addition, the child cross-section generation unit 43 generates a child cross-section group according to the procedure described with reference to FIG. 5 based on the plurality of child reference points, child counter-bank points, and child reference angles set by the above processing.

Returning to FIG. 2, the coordinate calculation unit 44 projects the planar grid 10 onto the CAD data, and calculates the Z coordinate on the CAD data that matches the XY coordinate of the feature point 101 as the Z coordinate of the feature point 101. Thereby, the Z coordinate is given to the feature point 101 arranged on the XY plane.
Here, the coordinate calculation unit 44 will be described in more detail with reference to FIG. FIG. 11 is a schematic diagram showing a cross-sectional shape of CAD data. Referring to FIG. 11, since the product unit 91 and the die face unit 95 have shape data stored in the storage device 8 in advance, the Z coordinate of the feature point 101 projected on the product unit 91 and the die face unit 95 is The shape data of the product part 91 and the die face part 95 can be easily obtained. On the other hand, since shape data is not set for the surplus portion 93, a device for appropriately acquiring the Z coordinate of the feature point 101 projected on the surplus portion 93 is required.
Returning to FIG. 2, the coordinate calculation unit 44 includes a determination unit 46, a first Z coordinate calculation unit 47, and a second Z coordinate calculation unit 48.

The determination unit 46 determines whether or not shape data is set at a position on the CAD data that matches the XY coordinates of the projected feature point 101. Here, even if it is the surplus portion 93, since the parameter that defines the cross section is set for the portion where the parent cross section 931 or the sub cross section groups 933 and 935 are set, the feature point 101 is projected The Z coordinate can be easily obtained. Therefore, whether or not the shape data is set indicates whether or not the product part 91, the die face part 95, the parent section 931, or the child section groups 933 and 935 are present at a position that coincides with the XY coordinates of the feature point 101. It is synonymous with judging.
More specifically, the determination unit 46 determines whether or not the feature point 101 is projected on the CAD surface (the product unit 91 and the die face unit 95). In addition, the determination unit 46 has an intermediate shape cross section at the point Q where the feature point 101 is a cross-sectional area (the surplus portion 93 in which the parent cross-section 931 or the child cross-section groups 933 and 935 are set and the product portion 91 is difficult to form. It is determined whether or not the image has been projected within the position 915.

  The first Z coordinate calculation unit 47 functions when the product part 91, the die face part 95, the parent cross section 931, or the child cross section groups 933 and 935 exist at a position that coincides with the XY coordinates of the feature point 101. 91, the Z coordinate of the feature point 101 is calculated based on the shape data (section parameters) of the die face portion 95, the parent section 931 or the child section groups 933 and 935. Specifically, the first Z coordinate calculation unit 47 calculates the Z coordinates of the product part 91, the die face part 95, the parent cross section 931, or the child cross section groups 933 and 935 at a position coinciding with the XY coordinates of the feature point 101. The Z coordinate of the feature point 101 is calculated.

Here, since the child section groups 933 and 935 are generated at the same pitch, the feature point 101 projected onto the child section group 933 may be projected onto the child section group 935 at the same time. In this regard, with reference to FIG. 12, a method for calculating the Z coordinate of the feature point 101A projected on both of the child section groups 933 and 935 will be described.
Referring to FIG. 12A, let Z be the Z coordinate of feature point 101A projected onto child section group 933, and let Zb be the Z coordinate of feature point 101A projected onto child section group 935. The child section group 933 is generated based on the parameters of the parent section 931A, while the child section group 935 is generated based on the parameters of the parent section 931B, and therefore the Z coordinates Za and Zb may be different from each other. . Therefore, the first Z coordinate calculation unit 47 performs weighting on the Z coordinates Za and Zb based on the distances to the parent cross sections 931A and 931B, and calculates the Z coordinate of the feature point 101A.

Specifically, as shown in FIG. 12B, the first Z coordinate calculation unit 47 calculates the distance D1 between the infinite straight line passing through the feature point 101A parallel to the Z direction and the parent cross section 931A, the infinite straight line, and A distance D2 from the parent cross section 931B is calculated, and a Z coordinate Z1 of the feature point 101A is calculated by the following equation (1). The distance between the infinite line and the parent cross sections 931A and 931B is the distance from the infinite line to the closest point on the parent sections 931A and 931B with respect to the infinite line.

Returning to FIG. 2, the second Z coordinate calculation unit 48 determines that the product part 91, the die face part 95, the parent cross section 931, and the child cross section groups 933 and 935 do not exist at positions that coincide with the XY coordinates of the feature point 101. The Z coordinate of the feature point 101 is calculated from the shape around the feature point 101. The peripheral shape means an arbitrary position where the Z coordinate can be specified. For example, the product part 91, the die face part 95, and the parent cross section 931 around an infinite straight line parallel to the Z direction passing through the feature point 101. Or the child cross-sectional group 933,935 is said.
The second Z coordinate calculation unit 48 includes a candidate cross section acquisition unit 481, a closest point acquisition unit 482, and a coordinate calculation unit 483.

  The candidate section acquisition unit 481 acquires two or more child sections that cross an infinite straight line that passes through the feature point 101 and is parallel to the Z direction as candidate sections. At this time, the candidate section acquisition unit 481 acquires two or more candidate sections for each of the child section groups 933 and 935. Note that the two or more child cross-sections straddling the infinite straight line mean two or more child cross-sections in the vicinity of the infinite straight line. The closest point acquisition unit 482 calculates the closest point with respect to the infinite straight line passing through the feature point 101 for each of the acquired plurality of candidate cross sections, and acquires the Z coordinate of the closest point. The coordinate calculation unit 483 calculates the Z coordinate of the feature point 101 by weighting the Z coordinate of the nearest point on the candidate cross section based on the distance from the infinite line.

  Here, an example of a Z coordinate calculation method by the second Z coordinate calculation unit 48 will be specifically described with reference to FIG. The calculation of the Z coordinate by the second Z coordinate calculation unit 48 includes the calculation of the Z coordinate (first candidate coordinate) based on the child cross section group 933 (FIG. 13A) and the Z coordinate (the first coordinate based on the child cross section group 935). (2 candidate coordinates) is calculated (FIG. 13B), and Z coordinates are calculated based on the first candidate coordinates and the second candidate coordinates (FIG. 13C).

Referring to FIG. 13A, feature point 101B is a feature point at which product part 91, die face part 95, parent section 931, and child section groups 933 and 935 do not exist in the corresponding XY coordinates.
First, the second Z coordinate calculation unit 48 (candidate section acquisition unit 481) sets an infinite straight line that passes through the feature point 101B and is parallel to the Z direction. Then, the second Z coordinate calculation unit 48 (candidate section acquisition unit 481) acquires, as candidate sections, two subsection groups 933A and 933B that straddle the infinite straight line when viewed in the Z direction from among the plurality of subsection groups 933. To do.

  Subsequently, the second Z coordinate calculation unit 48 (nearest point acquisition unit 482) calculates the nearest point with respect to the infinite straight line for the child section groups 933A and 933B acquired as candidate slices, and acquires the Z coordinate of the nearest point. To do. In FIG. 13A, the nearest point P1 is calculated for the child cross section group 933A, and the Z coordinate Z3 of this nearest point P1 is acquired. In addition, the nearest point P2 is calculated for the child sectional group 933B, and the Z coordinate Z4 of the nearest point P2 is obtained.

Subsequently, the second Z coordinate calculation unit 48 (coordinate calculation unit 483) weights the Z coordinates Z3 and Z4 of the nearest points P1 and P2 based on the distance from the infinite line to the nearest points P1 and P2, First candidate coordinates Za are calculated. As an example, when the distance from the infinite line to the nearest point P1 is D3 and the distance from the infinite line to the nearest point P2 is D4, the second Z coordinate calculating unit 48 (coordinate calculating unit 483) has the following formula ( The first candidate coordinate Za is calculated according to 2).

Referring to FIG. 13B, subsequently, the second Z coordinate calculation unit 48 acquires candidate cross sections (child cross section groups 935A and 935B) in the same manner for the child cross section group 935, and on this candidate cross section, Z coordinates (Z coordinates Z5, Z6) of the nearest points (nearest points P3, P4) are acquired. Then, the second Z coordinate calculation unit 48 performs weighting based on the distance from the infinite straight line, and calculates the second candidate coordinate Zb. As an example, when the distance from the infinite line to the nearest point P3 is D5 and the distance from the infinite line to the nearest point P4 is D6, the second Z coordinate calculation unit 48 uses the following equation (3) to calculate the second candidate. The coordinate Zb is calculated.

  Thereby, the first candidate coordinates Za based on the child section group 933 and the second candidate coordinates Zb based on the child section group 935 are calculated.

Here, the child section group 933 and 935 are generated between the parent sections 931A and 931B, and the child section group 933 is generated from the parent section 931A toward the parent section 931B based on the section parameter of the parent section 931A. The child section group 935 is generated from the parent section 931B toward the parent section 931A based on the section parameter of the parent section 931B. Since the panel product has a continuous shape, the child cross-section group 933 near the parent cross-section 931A is generated with higher accuracy than the child cross-section group 933 far from the parent cross-section 931A (close to the parent cross-section 931B). it is conceivable that. The same applies to the parent cross section 931B and the child cross section group 935.
Therefore, the second Z coordinate calculation unit 48 determines the distance from the parent cross sections 931A and 931B with respect to the first candidate coordinates Za based on the child cross section group 933 and the second candidate coordinates Zb based on the child cross section group 935. Based on the weighting, the Z coordinate Z7 of the feature point 101B is calculated.

Specifically, referring to FIG. 13C, when the distance between the infinite straight line passing through the feature point 101B and the parent cross section 931A is D7, and the distance between the infinite straight line and the parent cross section 931B is D8, The Z-coordinate Z7 of the feature point 101B is calculated according to equation (4).

  In this way, the first Z coordinate calculation unit 47 calculates the Z coordinate of the feature point 101 projected onto the product unit 91, the die face unit 95, the parent cross section 931, or the child cross section group 933, 935, and the second The Z coordinate calculation unit 47 calculates the Z coordinate of the feature point 101 projected on the surplus portion 93 where the parent cross section 931 and the child cross section groups 933 and 935 are not set. Since each feature point 101 has an XY coordinate defined in advance, the XYZ coordinate of each feature point 101 is calculated along with the calculation of the Z coordinate.

Returning to FIG. 2, the draw model generation unit 45 includes faces generated based on a plurality of parent cross sections and a plurality of child cross sections by connecting the feature points 101 from which the XYZ coordinates are obtained to polygons. A simple interpolation plane is generated as a polygon plane. For example, when adjacent feature points 101 are connected, a triangular polygon 102 can be created (see FIG. 1C). Thereby, the draw model 9 (for example, refer FIG. 20) of the press molded product containing the surplus part 93 in which CAD data does not exist is produced | generated.
Note that the interval (XY coordinates) between the feature points 101 is set to an optimum interval Dopt determined so as not to cause an error in the portion of the panel product where the polygon has the largest bending angle. Therefore, depending on the part, the interval between the feature points 101 may be unnecessarily fine and the calculation amount may be enormous. Therefore, the draw model generation unit 45 deletes (decimates) unnecessary feature points 101. Also good. As an example, when the difference between the Z coordinates of the adjacent feature points 101 is less than the threshold value, in other words, when the change of the Z coordinates in the adjacent feature points 101 is small, the feature points 101 may be deleted.

  Returning to FIG. 2, the function of the parallel calculation management unit 49 will be described. Of the functions configured in the arithmetic unit 4 of the main computer PC0 described above, the calculation in the child cross-section generating unit 43 has a large amount of work and takes time. In particular, among the calculations in the child section generation unit 43, the calculation for generating the child section groups 933 and 935 having a shape similar to the parent sections 931A and 931B under a predetermined constraint condition is particularly heavy. Therefore, in the draw model generation system 1 according to the present embodiment, the calculation related to generation of the child cross-section group in the child cross-section generation unit 43 is executed in parallel by a plurality of computers PC1... PCN of the parallel computer PCC. The time required for generating the child cross section group is reduced. The parallel calculation management unit 49 executes preparatory processing necessary for operating the parallel computer PCC as efficiently as possible in the shortest possible time, and integration processing of calculation results in the parallel column computer PCC. The parallel calculation management unit 49 includes a workload estimation calculation unit 491, a shared area setting unit 492, a divided data generation unit 493, and a child cross-section data integration unit 494 as modules for executing the above preparation processing and integration processing. Prepare. Hereinafter, functions of these modules 491 to 494 will be described in order.

  The work amount estimation calculation unit 491 calculates the value of the work amount parameter W correlated with the total number of child cross sections that need to be generated. As described above, in the calculation in the child section generation unit 43, the load of calculation for generating a child section having a similar shape from the parent section under a predetermined constraint condition is high. Therefore, the work required for generating the child cross section group is approximately proportional to the total number of child cross sections that need to be generated. The work amount estimation calculation unit 491 calculates the value of the work parameter W defined as described above before actually starting the generation of the child cross section group, and estimates the work amount necessary for generating the child cross section group. .

  Various parameters can be adopted as the work amount parameter W. First, as described with reference to FIG. 7, the child cross sections are generated at predetermined intervals along the reference line. Therefore, the longer the reference line, the greater the number of child cross sections that need to be generated. Therefore, the work amount estimation calculation unit 491 may calculate the length of the reference line and use this as the value of the work amount parameter W. The length of the reference line may be the length of the reference line in the three-dimensional space, or may be the length of the reference line in plan view as shown in FIG. In order to shorten the estimation time as much as possible, the length of the reference line in plan view is preferably set as the work parameter W.

  In addition, by defining the length of the reference line as the work parameter W in this way, there is an advantage that the value of the work parameter W can be calculated in a relatively short time. However, as described with reference to FIG. 7, since the child cross section may be generated by dividing the cross section along the reference line at a constant initial pitch Pdef, it may be generated. The accuracy is low. Therefore, the work amount estimation calculation unit 491 simply calculates the number of child reference points by executing the operation shown in FIG. It may be a value. Here, when the calculation shown in FIG. 7 is executed in plan view, the reference line and the opposite bank line having a three-dimensional shape are projected on the XY coordinate plane, and the processes of steps S51 to S66 are executed in the two-dimensional plane. Means. In this way, by executing a simple calculation in the two-dimensional plane, the value of the work parameter W can be calculated more accurately in a short time.

  The shared area setting unit 492 divides the area for generating the child cross section group into N areas that are the number of computers PC1 to PCN responsible for generating the child cross section group, and generates the child cross section group by each of the computers PC1 to PCN. Sort areas.

  FIG. 14 is a diagram schematically showing N areas AR <b> 1 to ARN distributed to N computers by the assigned area setting unit 492. The shared area setting unit 492 is configured so that the calculation loads of the computers PC1 to PCN are equally distributed, in other words, the area work parameters W1 to WN corresponding to the areas AR1 to ARN are equalized (W1≈ W2≈... WN≈W / N), the region for generating the child cross-section group is divided. Here, the area work parameters W1 to WN correspond to the length of the reference line included in the corresponding area when the work parameter W is defined by the length of the reference line. When defined by the number of points, it corresponds to the number of reference points included in the corresponding region.

  The divided data generation unit 493 prepares data necessary for generating child sectional groups in the distributed areas AR1 to ARN by the computers PC1 to PCN, and transmits the data to the computers PC1 to PCN. Here, the data necessary for generating the child sectional groups in each of the areas AR1 to ARN includes at least data relating to the shape parameters of the parent section belonging to each of the areas AR1 to ARN, the reference line belonging to the area, and the opposite bank line. CAD data necessary for specifying the length, shape, etc.

  In particular, here, the divided data generation unit 493 cuts out the CAD data to be transmitted to each of the computers PC1 to PCN by the amount belonging to each of the areas AR1 to ARN, thereby individually generating the partial CAD so that the capacity is minimized. It is preferable to transmit data. Each of the computers PC1 to PCN generates a child sectional group by sequentially referring to CAD data stored in each storage device. Here, when the CAD data referred to by each of the computers PC1 to PCN includes CAD data related to a region unrelated to the region that the computer itself handles, unexpected time may be consumed in referencing the CAD data. . Therefore, the divided data generation unit 493 preferably transmits partial CAD data generated by cutting out each area to each computer in order to minimize the time loss required for referencing such CAD data.

  Based on the data transmitted from the divided data generation unit 493, each of the computers PC1 to PCN simultaneously generates a child cross-section group in the area AR1 to ARN that the computer PC1 to PCN serves according to the same procedure as the above-described child cross-section generation unit 43.

  The child cross-section data integration unit 494 receives data related to the shape parameters of the child cross-section groups generated by the computers PC1 to PCN, and can refer to the data by calculation in the coordinate calculation unit 44 and the draw model generation unit 45 described above. Are combined and stored in the storage device 8.

[Generate intermediate shape draw model]
By the way, due to the material characteristics of the plate material to be pressed, the product shape may not be formed by a single press process. In such a case, the plate material is first pressed to an intermediate shape and then the intermediate shape is processed. Trying to get shape. When the intermediate shape is pressed prior to the product shape, in the model shape evaluation by CAE, it is necessary to evaluate whether the intermediate shape can be processed instead of the product shape.
Therefore, in the draw model generation system 1 of the present invention, an intermediate shape draw model is also generated as necessary.

That is, the parent cross-section setting unit 42 sets a plurality of intermediate cross-section parent cross sections at arbitrary positions of the product part 91 that are difficult to be formed by a single press process due to the relationship of material characteristics. A child cross section is generated between these parent cross sections. Then, the coordinate calculation unit 44 projects the plane lattice 10 onto the intermediate cross-section parent and child cross-sections set in the product unit 91, and determines the Z-coordinate of the intermediate cross-section that matches the XY coordinates of the feature point 101. , And calculated as the Z coordinate of the feature point 101. Then, the draw model generation unit 45 connects the feature points 101 from which the XYZ coordinates are obtained to form a polygon. Thereby, the intermediate shape produced | generated in the press work process is acquirable.
Depending on the XY coordinates of the feature point 101, an intermediate cross section may not be set at the corresponding position. In such a case, by performing the predetermined weighting as described above, it is possible to calculate the Z coordinate of the feature point 101 to be projected at a position where the intermediate cross section is not set.

  Here, with reference to FIG. 15, the flow in the case of generating an intermediate-shaped draw model will be specifically described. FIG. 15A is a diagram schematically showing a cross section of the draw model 9. FIGS. 15B and 15C are diagrams illustrating a method of calculating the Z coordinate of the feature point 101 projected onto the cross section of the intermediate shape, and FIG. 15B illustrates the intermediate shape at the projected position. FIG. 15C is a cross-sectional view illustrating a calculation method when a cross-section (parent cross-section or child cross-section) is set, and FIG. 15C illustrates an intermediate cross-section (parent cross-section and child cross-section) set at the projected position. It is a perspective view which shows the calculation method when there is not.

With reference to FIG. 15 (A), the product part 91 has a portion Q that is difficult to be formed by a single press work due to the relationship between the material properties of the plate material. Therefore, as shown in FIG. 15B, the parent cross-section setting unit 42 sets a plurality of intermediate-shaped parent cross sections at this location Q, and the child cross-section generating unit 43 sets the intermediate-shaped child cross-section between these parent cross-sections. Generate multiple cross sections. The intermediate-shaped parent cross-section or child cross-section is hereinafter referred to as “intermediate-shaped cross-section 915”. The method for setting (generating) the intermediate-shaped section 915 is the same as the section (parent section or child section) that is set (generated) in the surplus portion 93, and is therefore omitted.
In addition, the cross section (intermediate-shaped cross section 915) set to the location Q and the cross sections (parent cross section 931, child cross section groups 933 and 935) set to the surplus portion 93 may be integrated, or respectively. Individual cross-sections may be used.

  When the intermediate-shaped cross section 915 is set, the coordinate calculation unit 44 projects the planar lattice 10. Here, since the cross section 915 having the intermediate shape is set with respect to the product portion 91, when the XY coordinate of the feature point 101 coincides with an arbitrary position of the cross section 915 having the intermediate shape, the feature point 101 has the intermediate shape. Are projected on both the cross section 915 and the product portion 91. In FIG. 15B, the feature point 101 is projected onto the Z coordinate Z8 of the cross section 915 having the intermediate shape and the Z coordinate Z9 of the product portion 91.

  In such a case, the coordinate calculation unit 44 (first Z coordinate calculation unit 47) performs the Z coordinate Z8 of the intermediate cross section 915 at the position coinciding with the XY coordinates of the feature point 101 and the Z coordinate Z9 of the product unit 91. Among these, the Z coordinate having a larger value is calculated as the Z coordinate of the feature point 101. Since the intermediate-shaped section 915 is set above the product portion 91 in the Z direction, a larger value of the Z-coordinate is basically the Z-coordinate (Z8) of the intermediate-shaped section 915. Become.

On the other hand, when the feature point 101 is projected to a position where the intermediate-shaped section 915 is not set, the coordinate calculation unit 44 functions as the second Z-coordinate calculation unit 48, and the intermediate shape set in the periphery The Z coordinate of the feature point 101 is calculated using the cross section 915.
That is, as shown in FIG. 15C, the coordinate calculation unit 44 (second Z coordinate calculation unit 48) has two intermediate-shaped cross sections 915A, straddling an infinite straight line passing through the feature point 101 and parallel to the Z direction. 915B is acquired, and the nearest points P5 and P6 with the infinite straight line passing through the feature point 101 are calculated from the intermediate-shaped cross sections 915A and 915B. Then, the Z coordinates Z10 and Z11 of the nearest points P5 and P6 are weighted based on the distance from the infinite line, and the Z coordinate of the feature point 101 is calculated. Details are as described above.

[Draw model generation system processing]
16 to 18 are flowcharts showing the flow of processing of the draw model generation system 1. As shown in FIG. 16, the draw model is generated by using the preparation process for setting the shape data of the product part 91 and the die face part 95 and the plane lattice 10 and the data prepared in this preparation process. Generating a draw model. More specifically, the preparation process is configured by the processes of steps S1 to S4, and the draw model generation process is configured of the processes of steps S5 to S8.

  In step S <b> 1, based on the operation of the input device 2 by the operator, the main computer PC <b> 0 generates shape data of the product unit 91 and the die face unit 95 and stores them in the storage device 8. In step S2, the parent cross section setting unit 42 of the main computer PC0, based on the operation of the input device 2 by the operator, has a plurality of parent cross sections (the parent cross section of the surplus portion 93, the intermediate cross section so as not to cross each other as described above). A parent cross section of the shape is set and stored in the storage device 8.

  In step S3, the main computer PC0 and the parallel computer PCC use the operation of the input device 2 by the operator and the cross-sectional parameters of the plurality of parent cross-sections set as described above, and the child cross-section groups between the parent cross-sections. The child cross-section group generation process for generating is executed. Here, a detailed procedure of the child section group generation processing will be described with reference to the flowchart of FIG.

  In step S31, the work amount estimation calculation unit 491 of the main computer PC0 calculates the value of the work amount parameter W. Here, the work parameter W is the length of the reference line or the number of child reference points as described above.

  In step S32, the shared area setting unit 492 of the main computer PC0 assigns the areas for generating the child cross-sectional groups to the areas AR1 to ARN that are assigned to the computers PC1 to PCN so that the loads of the computers PC1 to PCN are equalized. To divide.

  In step S33, the divided data generation unit 943 of the main computer PC0 receives data and partial CAD data on the shape parameters of the parent cross section necessary for generating the child cross section groups in the areas AR1 to ARN in the respective computers PC1 to PCN. It is generated and transmitted to each of the computers PC1 to PCN.

  In step S34, each of the computers PC1 to PCN of the parallel computer PCC generates child sectional groups in the areas AR1 to ARN shared by each computer based on the data transmitted from the main computer PC0.

  In step S <b> 35, the child section data integration unit 494 of the main computer PC <b> 0 integrates data related to the shape parameters and the like of the child section groups generated by the computers PC <b> 1 to PCN and stores them in the storage device 8.

  Here, a preferable number of computers PC1 to PCN that execute parallel calculation for generating a child section group will be described. If the total number of child cross sections to be generated, that is, the total work amount is constant, the work amount assigned to each computer decreases as the number of computers increases, and the time required for the parallel processing in step S34 decreases. However, as the number of computers is increased, the time required for preparation of steps S31 to S33 becomes longer. Therefore, the number N of computers is determined by experiments so that the total processing time including the parallel processing time and the preparation processing time is minimized.

  Returning to FIG. 16, in step S <b> 4, the plane grid generator 41 of the main computer PC <b> 0 generates the plane grid 10 based on the operation of the input device 2 by the operator and stores it in the storage device 8. In step S5, the coordinate calculation unit 44 of the main computer PC0 projects the planar grid 10 onto the product unit 91, the die face unit 95, the shape data (CAD data) of the parent cross section and the child cross section. In step S6, the coordinate calculation unit 44 performs Z coordinate calculation processing. Here, the Z coordinate calculation process will be described with reference to FIG.

  In step S11, the determination unit 46 determines whether or not the feature point 101 is projected on the CAD plane. Here, the CAD surface refers to the product part 91 and the die face part 95. That is, when the feature point 101 is projected onto the product portion 91 or the die face portion 95, YES is obtained in step S11, and the feature point 101 is located at a position other than the product portion 91 and the die face portion 95, that is, within a cross-sectional area described later. If projected, NO in step S11.

  When YES in step S11, in step S12, the first Z coordinate calculation unit 47 acquires the Z coordinates of the product part 91 and the die face part 95 at the projected positions, and moves the process to step S13.

  In step S <b> 13, the determination unit 46 determines whether or not the feature point 101 is projected in the cross-sectional area. Here, the cross-sectional area is an area where a cross-section is set. Specifically, a surplus part 93 where a parent cross-section 931 or a sub-section group 933, 935 is set and a product part 91 are formed. This is the position where the intermediate section 915 is set at the difficult point Q. That is, when the feature point 101 is projected to the position where the surplus portion 93 or the intermediate cross section 915 is set, YES is determined in step S13, and the process proceeds to step S14. On the other hand, if NO at step S13, the process proceeds to step S19.

  In step S <b> 14, the determination unit 46 determines whether a cross section exists at a position that matches the XY coordinates of the feature point 101. That is, at the position coincident with the XY coordinates of the feature point 101, the parent cross section 931 or the sub cross section groups 933 and 935 set in the surplus portion 93 and the intermediate shape set in the difficult part Q of the product portion 91 are formed. If there is no cross section 915, NO is determined in step S14, and the process proceeds to step S15.

In step S <b> 15, the second Z coordinate calculation unit 48 acquires the child cross-sectional groups 933 and 935 that cross the infinite straight line that passes through the feature point 101 and is parallel to the Z direction, and infinite on the child cross-sectional groups 933 and 935. Extract the nearest point with a straight line. Subsequently, in step S16, the second Z coordinate calculation unit 48 weights the Z coordinate of the nearest point based on the distance to the infinite straight line, and based on the first candidate coordinates based on the child section group 933 and the child section group 935. Second candidate coordinates are calculated. In subsequent step S <b> 17, the second Z coordinate calculation unit 48 weights the first candidate coordinates and the second candidate coordinates based on the distance to the parent cross section 931, and calculates and acquires the Z coordinate of the feature point 101. . After obtaining the Z coordinate, the process proceeds to step S19.
It should be noted that the above equations (2) and (3) are used for calculating the first candidate coordinates and the second candidate coordinates in step S16, and the above equation (4) is used for calculating the Z coordinates in step S17. .
In the description of steps S15 to S17 described above, the case where the Z coordinate is acquired in the surplus portion 93 in which the parent section 931 or the child section groups 933 and 935 is set has been described. The same applies when the Z coordinate is acquired at the position where the cross section 915 is set.

  Returning to step S <b> 14, the parent cross section 931 or the sub cross section groups 933 and 935 set in the surplus portion 93 and the difficult part Q of the product portion 91 are set at a position coinciding with the XY coordinates of the feature point 101. If the intermediate-shaped cross section 915 exists, YES is determined in step S14, and the process proceeds to step S18.

In step S <b> 18, the first Z coordinate calculation unit 47 calculates and acquires the Z coordinate based on the cross-sectional parameter of each cross-section. Specifically, the Z coordinate of the parent cross section 931, the child cross section groups 933 and 935, or the intermediate cross section 915 is calculated and acquired as the Z coordinate of the feature point 101, and the process proceeds to step S19.
Here, when the feature point 101 is projected on both the child section groups 933 and 935, the Z coordinate Za of the feature point 101 projected on the child section group 933 and the feature point projected on the child section group 935. The Z coordinate Zb of 101 is weighted based on the distance to the parent cross sections 931A and 931B, and the Z coordinate of the feature point 101 is calculated. Note that the above equation (1) is used to calculate the Z coordinate in such a case.
In the description of step S18 described above, the case where the Z coordinate is calculated based on the sectional parameters of the child sectional groups 933 and 935 set in the surplus portion 93 has been described. The same applies to the case where the Z coordinate is acquired based on the child cross section at the position where 915 is set.

In step S <b> 19, when there are two acquired Z coordinates, the larger Z coordinate is acquired as the Z coordinate of the feature point 101. Here, the case where there are two acquired Z coordinates is YES in both step S11 and step S13, and the feature point 101 is an intermediate-shaped cross section 915 at a difficult part Q in the product portion 91. This is a case of projecting to the set position. In this case, there are two, the Z coordinate acquired in step S12 and the Z coordinate acquired in step S17 or 18. Accordingly, the larger one (basically, the Z coordinate acquired in step S17 or 18) is acquired as the Z coordinate of the feature point 101, and the process proceeds to step S20.
By the way, in principle, there is no region where neither the CAD plane nor the cross section exists. Therefore, in at least one of step S11 and step S13, the answer is always YES, and the Z coordinate is acquired. For safety, faces of three or more sides may be automatically created by already known software and linked with a polygon hole filling process for filling a holed area on a polygon mesh or a polygon grid.

  In step S20, the Z coordinate acquired in step S19 is associated with the XY coordinate of the feature point 101 and stored in the storage device 8. Thereafter, the process proceeds to step S21, the process is performed for all the feature points 101, and the Z coordinate calculation process is terminated.

  Returning to FIG. 16, when the Z coordinates are calculated for all the feature points 101 (that is, the XYZ coordinates are acquired), the draw model generation unit 45 deletes the unnecessary feature points 101 in step S6. Specifically, the draw model generation unit 45 deletes the feature point 101 when the change in the Z coordinate is small at the adjacent feature point 101. Subsequently, in step S <b> 7, the draw model generation unit 45 connects adjacent feature points 101 to form a polygon, and ends the process.

[Second Embodiment]
Next, a draw model generation system to which the interpolation plane generation method according to the second embodiment of the present invention is applied will be described with reference to FIGS. In the following description of the second embodiment, the same components and processes as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The draw model generation system according to the present embodiment has a function of the child section generation unit, that is, a specific procedure for generating a plurality of child sections between the parent sections described with reference to FIGS. Different from form. Further, the first embodiment has been described assuming that the pair of parent cross sections is a plane. On the other hand, the second embodiment is different from the first embodiment in that it is generalized when the pair of parent cross sections is not a plane.

FIG. 21 is a main flowchart showing a specific procedure for setting a plurality of child cross sections between a selected pair of parent cross sections.
First, in step S91, the child cross-section generating unit determines whether the pair of parent cross-sections are planar or non-planar. Here, the planar parent cross section refers to a pair of parent cross sections 931A and 931B that are linear when viewed in plan along the Z-axis as shown in FIG. 23 (or FIG. 6 described later). Say things. Further, the non-planar parent cross section means that the pair of parent cross sections 931A and 931B can be seen in a curved shape when viewed in plan along the Z axis as shown in FIG. Whether the pair of parent cross sections is planar or non-planar may be automatically determined using a predetermined algorithm, or may be manually determined by an operator based on visual observation. .

  If it is determined in S91 that the parent cross section is planar, the process proceeds to S92, and a child cross section is generated by a relatively simple method in accordance with the planar parent cross section (see FIG. 22 described later). Exit. If it is determined that the parent cross section is non-planar, the process proceeds to S93, and a child cross section is generated by a relatively complicated method in accordance with the non-planar parent cross section (see FIG. 24 described later). End the process.

FIG. 22 is a flowchart showing a specific procedure for setting a child cross section when the parent cross section is planar.
FIG. 23 is a plan view of a child cross section generated between the pair of parent cross sections 931A and 931B by the process shown in FIG. 22 along the Z axis.

  First, in step S101, the child section generation unit acquires three-dimensional coordinate information of the selected parent sections 931A and 931B, the reference line BL, and the opposite bank line OL, and based on the acquired information, the parent reference point BP1, BP2 and parent counter points OP1 and OP2 are calculated.

  In step S102, the child cross-section generating unit sets a child reference point BPC as a starting point at a predetermined position on the reference line BL between the two parent reference points BP1 and BP2. The position where the child reference point BPC is set may be determined manually by the operator, or may be automatically determined based on a predetermined setting parameter as in S52 of FIG.

  In step S103, the child cross-section generation unit calculates the priority ratio BR of the child reference point BPC determined as the start point in S102. Here, the priority ratio of the child reference point is the distance along the reference line BL from one of the two parent reference points BP1 and BP2 (hereinafter referred to as the parent reference point BP1) to the child reference point BPC. The ratio of the distance along the reference line BL from the parent reference point BP1 to the parent reference point BP2 (distance BP1 to BPC / distance BP1 to BP2).

  In step S104, the child cross-section generating unit sets a child opposite bank point OPC as an end point at the same ratio as the priority ratio BR calculated in step S103 between two parent opposite bank points OP1 and OP2 on the opposite bank line OL. Here, the priority ratio of the child shore point is the distance from one of the two parent shore points OP1 and OP2 (which is the parent shore point OP1 in accordance with the above definition on the base line side) to the child shore point OPC. It is the ratio of the distance along the opposite shoreline OL and the distance along the opposite shoreline OL from the parent opposite shore point OP1 to the parent opposite shore point OP2 (distance between OP1 and OPC / distance between OP1 and OP2).

  In step S105, the child cross-section generation unit generates a child cross-section as shown by a broken line in FIG. 22 according to the child reference point BPC and the child opposite point OPC set as described above. More specifically, a child cross section that intersects the reference line BL and the opposite bank line OL and includes the child reference point BPC and the child opposite bank point OPC is generated by applying a known plane interpolation algorithm.

  In step S106, the child section generation unit determines whether or not a child section needs to be generated. If this determination is YES, the process returns to step S102 to generate a child cross section. If this determination is NO, this process is immediately terminated.

FIG. 24 is a flowchart showing a specific procedure for setting a child cross section when the parent cross section is non-planar.
FIG. 25 is a plan view of a plurality of child cross sections generated between a pair of non-planar parent cross sections 931A and 931B by the process shown in FIG. 24 along the Z axis.

  First, in step S111, the child section generation unit acquires three-dimensional coordinate information of the selected parent sections 931A, 931B, the reference line BL, and the opposite bank line OL, and based on the acquired information, the parent reference points BP1, BP2 and parent-facing points OP1, OP2, parent reference angles θ1, θ2, and parent-facing angles φ1, φ2 are calculated. Here, the parent reference angle refers to the angle formed between the parent cross section and the reference line when viewed in plan along the Z axis, and the parent-to-bank angle refers to the parent cross section when viewed in plan along the Z axis. The angle formed with the opposite bank (see Fig. 25).

In step S112, the child cross-section generating unit sets a child reference point BPC as a starting point at a predetermined position on the reference line BL between the two parent reference points BP1 and BP2. The position where the child reference point BPC is set may be determined manually by the operator, or may be automatically determined based on a predetermined setting parameter as in S52 of FIG.
In step S113, the child cross-section generator calculates the priority ratio BR of the child reference point BPC determined as the starting point in S112.

  In step S114, the child cross-section generating unit calculates a child reference angle θC corresponding to the child reference point BPC based on the two parent reference angles θ1 and θ2 and the priority ratio BR. More specifically, as in S54 of FIG. 7, the lower the priority ratio (that is, the closer the child reference point BPC is to the parent reference point BP1), the closer to the parent reference angle θ1, and the higher the priority ratio ( That is, the child reference angle θC is determined so as to be closer to the parent reference angle θ2 as the child reference point BPC is closer to the parent reference point BP2.

Moreover, such calculation of the child reference angle can be realized by constructing a map as shown in FIG. 26 based on the two parent reference angles θ1 and θ2.
As shown in FIG. 26, two points that specify two parent reference points BP1 and BP2 in a two-dimensional coordinate system in which the vertical axis is a reference angle (deg) and the horizontal axis is a priority ratio that can take a value of 0 to 1. , And linear interpolation or smooth curve interpolation between these two points makes it possible to construct a map for uniquely specifying the priority ratio of each child reference point and the reference angle at that point.

  Returning to FIG. 24, in step S115, the child cross-section generating unit between the two parent counter-bank points OP1 and OP2 on the counter-bank line OL has the same ratio as the priority ratio BR calculated in step S113, and the child counter-bank point OPC as the end point. Set.

  In step S116, the child cross-section generating unit calculates a child opposite bank angle φC corresponding to the child opposite bank point OPC based on the two parent opposite bank angles φ1 and φ2 and the priority ratio BR. More specifically, similarly to the calculation of the child reference angle θC, a map similar to that of FIG. 26 is constructed based on the two child opposite bank angles φ1 and φ2, and the child opposite bank angle φC is calculated by using this map. be able to.

  In step S117, the child cross-section generation unit, as shown by a broken line in FIG. 25, in accordance with the child reference point BPC, the child opposite bank point OPC, the child reference angle θC, and the child opposite bank angle φC set as described above. A curved child section is generated. More specifically, a known curved surface interpolation algorithm is applied to a child cross section that intersects the reference line BL and the opposite shore line OL at the child reference angle θC and the child opposite shore angle φC and includes the child reference point BPC and the child opposite shore point OPC. And generate.

  In step S118, the child section generation unit determines whether or not a child section needs to be generated. If this determination is YES, the process returns to step S112 to generate a child cross section. If this determination is NO, this process is immediately terminated.

The preferred embodiment of the draw model generation system 1 of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and can be modified as appropriate.
For example, in the present embodiment, the feature points 101 are arranged in a grid pattern, but the present invention is not limited to this. That is, the feature points 101 need only have XY coordinates defined, and the present invention can be applied even if they are irregularly arranged.

  In the present embodiment, when the feature point 101 is projected onto the product portion 91 (YES in step S12 in FIG. 18), the Z coordinate is calculated using the cross section 915 having an intermediate shape. In this respect, it is sufficient to generate the intermediate shape only for the portion Q that is difficult to press, and it is not necessary to generate the intermediate shape for all of the product portions 91. That is, for the feature point 101 projected on the predetermined area (location Q) of the product part 91, a larger value is calculated as the Z coordinate between the Z coordinate of the product part 91 and the Z coordinate of the cross section 915 of the intermediate shape. For the feature point 101 projected outside the predetermined area (location Q) of the part 91, the Z coordinate of the product part 91 is calculated as the Z coordinate of the feature point 101.

In the present embodiment, as described with reference to FIG. 9, the necessity of division is determined using the distance D1 between reference points and the distance D2 between opposite shore points, but the present invention is not limited to this. For the necessity of division, a sag value or a curvature may be used instead of these distances D1 and D2. Here, the sag value is a parameter used for determining the division accuracy of the mesh, and can be calculated by the following formula when three points P1, P2, and P3 are given as shown in FIG.
h = a · b · sin θ / (a ² + b ² −2a · b · cos θ) ^1/2

  In the present embodiment, the case where the parallel computer PCC is used when executing the child section group generation processing in step S3 of FIG. 16 has been described, but the present invention is not limited to this. The parallel computer PCC may be used not only at step S3 but also when executing the processing of other steps S4 to S8.

DESCRIPTION OF SYMBOLS 1 Draw model production | generation system 2 Input device 4 Arithmetic unit 42 Parent cross-section production | generation part 43 Child cross-section production | generation part 9 Draw model 91 Product part 93 Extra part 931 Parent cross-section 933 Child cross-section 935 Child cross-section 95 Die face part PC0 Main computer PCC Parallel computer

Claims (4)

An interpolation surface generation method for generating an interpolation surface by a computer for interpolating between a reference line defined in a three-dimensional space and an opposite shore line facing the reference line,
A parent section setting step of setting a plurality of parent sections parallel to the Z axis between the reference line and the opposite bank line;
A child cross-section generating step for generating one or more child cross-sections parallel to the Z-axis between pairs of adjacent parent cross-sections among the plurality of parent cross-sections;
An interpolation surface generating step for generating the interpolation surface so as to include a surface defined based on the plurality of parent cross sections and the plurality of child cross sections,
In the child cross section generation step, an angle formed by one parent cross section and the reference line is a first parent angle, and an angle formed by the other parent cross section and the reference line is a second parent angle. And, based on the second parent angle, determine an angle formed by the child cross section between the parent cross section pair and the reference line;
An interpolation plane generating method, wherein an angle formed between the child section and the reference line is different from an angle formed between another child section adjacent to the child section or a parent section and the reference line. In the child cross section generation step, an angle formed by the plurality of child cross sections between the parent cross section pair and the reference line is determined between the first parent angle and the second parent angle, and In order from the child cross section on the one parent cross section side toward the child cross section on the other parent cross section side, changing from an angle close to the first parent angle to an angle close to the second parent angle. The method of generating an interpolation plane according to claim 1 , wherein the interpolation plane is generated. The child cross section generation step includes
Setting a starting point at a predetermined position on the reference line between the parent cross-section pairs;
Calculating a ratio between a distance between an intersection of one parent cross-section of the pair and the reference line and the start point, and a distance between an intersection of the pair of the parent cross-section and the reference line;
Setting a start point angle for the start point based on the first parent angle , the second parent angle, and a ratio calculated for the start point;
Setting an end point corresponding to the start point on the opposite bank at the same ratio as the calculated ratio;
An end point angle is set with respect to the end point based on the angle formed between the one parent cross section and the opposite shore line, the angle formed between the other parent cross section and the opposite shore line, and the calculated ratio. And a process of
The method includes: generating a child cross section that intersects the reference line and the opposite shore line at the start point angle and the end point angle and includes the start point and the end point, respectively. Interpolation plane generation method. An interpolation surface generation method for generating an interpolation surface by a computer for interpolating between a reference line defined in a three-dimensional space and an opposite shore line facing the reference line,
A parent section setting step of setting a plurality of parent sections parallel to the Z axis between the reference line and the opposite bank line;
A child cross-section generating step for generating one or more child cross-sections parallel to the Z-axis between pairs of adjacent parent cross-sections among the plurality of parent cross-sections;
An interpolation surface generating step for generating the interpolation surface so as to include a surface defined based on the plurality of parent cross sections and the plurality of child cross sections,
The child cross section generation step includes
Setting a starting point at a predetermined position on the reference line between the parent cross-section pairs;
Calculating a ratio between a distance between an intersection of one parent cross-section of the pair and the reference line and the start point, and a distance between an intersection of the pair of the parent cross-section and the reference line;
Based on the angle formed between the one parent cross section and the reference line, the angle formed between the other parent cross section and the reference line, and the ratio calculated with respect to the start point, with respect to the start point Setting the start point angle;
Setting an end point corresponding to the start point on the opposite bank at the same ratio as the calculated ratio;
Generating a child cross section that intersects with the reference line at the start point angle, intersects with the opposite bank line , and includes the start point and the end point.

Images