JP2018156145A - Contact determination program, contact determination method, and contact determination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To identify contact surfaces of a plurality of parts indicated by CAD data with high accuracy.SOLUTION: A contact determination device 100 acquires CAD data 101 of a 3-dimensional model including a first part and a second part. The contact determination device 100 identifies a first distance d1 between a first element e1 and a second element e2, on the basis of a normal of the first element e1 of elements expressing the first part, and a plane including the second element e2 of elements expressing the second part. The contact determination device 100 determines whether or not the first element e1 is brought into contact with the second element e2 according to the first distance d1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a contact determination program, a contact determination method, and a contact determination device.

  Conventionally, there is a technique for performing numerical analysis of a structure or the like. For example, in numerical analysis such as the finite element method, an analysis target region is divided into small regions, and equations in each small region are solved. In order to perform this numerical analysis, 3D for analysis is performed by performing mesh generation that divides the shape of the 3D model created for each part included in the structure by CAD (Computer Aided Design) into small regions. A model is created. This numerical analysis is performed using a three-dimensional model for analysis. A three-dimensional model in CAD represents each part by an element such as a triangle. The three-dimensional model for analysis represents each part by a small region having a shape such as a tetrahedron.

  As a prior art, the surface of a plurality of part models based on CAD data is divided into a plurality of surface elements, and a contact is made based on whether a normal vector of a surface element of one part model corresponds to a surface element of another part model. There is a technique for performing the determination (see, for example, Patent Document 1 below). In addition, as a prior art, when creating a three-dimensional model for analysis, a surface mesh that forms a closed space is generated on the surface of a three-dimensional shape by CAD data, and the surface between the surfaces constituting the shape surface is generated. When there is a gap, there is a technique for generating a surface mesh so as to share the same node on the boundary side of the adjacent surface (see, for example, Patent Document 2 below).

JP 2004-265050 A JP 2006-113802 A

  However, it may be difficult to specify contact surfaces of a plurality of parts included in the three-dimensional model indicated by the CAD data. For example, even if it is a part that actually becomes a contact surface of a plurality of parts, when each part is represented by a triangular element in CAD data, elements representing different parts corresponding to the contact surface do not match each other. There is. For example, if the size of each element is different, each element does not match. For this reason, for example, it is difficult to determine whether or not each element is a contact surface of a plurality of parts only by determining a match between elements representing different parts.

  In one aspect, an object of the present invention is to provide a contact determination program, a contact determination method, and a contact determination device that can accurately specify contact surfaces of a plurality of parts included in a three-dimensional model. .

  According to one aspect of the present invention, data of a three-dimensional model including a first part and a second part is acquired, and a normal line of a first element among elements representing the first part; A distance between the first element and the second element is specified based on a plane including the second element among elements representing the second part, and according to the distance, A contact determination program, a contact determination method, and a contact determination device for determining whether or not a first element and the second element are in contact with each other are proposed.

  According to one embodiment of the present invention, contact surfaces of a plurality of parts represented by CAD data can be specified with high accuracy.

FIG. 1 is an explanatory diagram illustrating an operation example of the contact determination device. FIG. 2 is an explanatory diagram illustrating an example of a three-dimensional model including a plurality of parts. FIG. 3 is an explanatory diagram illustrating an example of an analysis model obtained by mesh generation from a three-dimensional model. FIG. 4 is an explanatory diagram illustrating a hardware configuration example of the contact determination device 100. FIG. 5 is an explanatory diagram showing a data format example of the CAD data 101. FIG. 6 is a block diagram illustrating a functional configuration example of the contact determination device 100. FIG. 7 is a perspective view of the first component 201 and the second component 202. FIG. 8 is an explanatory diagram illustrating an example of a criterion for determining whether or not the contact surface. FIG. 9 is an explanatory diagram illustrating an output example. FIG. 10 is an explanatory diagram illustrating a specific example of a free edge. FIG. 11 is an explanatory diagram illustrating a specific example of an element sharing a vertex with the first free edge fe1. FIG. 12 is an explanatory diagram illustrating an example of deleting an element sharing a vertex with the first free edge fe1. FIG. 13 is an explanatory diagram illustrating an example in which a new element is generated. FIG. 14 is a flowchart illustrating an example of a processing procedure performed by the contact determination device 100. FIG. 15 is a flowchart showing a detailed description of the contact surface determination process shown in FIG. FIG. 16 is a flowchart showing a detailed description of the element generation processing shown in FIG.

  Exemplary embodiments of a contact determination program, a contact determination method, and a contact determination device according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram illustrating an operation example of the contact determination device. The contact determination device 100 is a computer that determines contact between the first component and the second component included in the three-dimensional model.

  Conventionally, for example, three-dimensional CAD data indicating a model in which the shape of a part is represented by a triangle (element) is created for each part included in the structure using CAD. The model is, for example, a structure including parts to be simulated on the computer space. The simulation space is a virtual space that is simulated on a computer. In the simulation space, for example, an orthogonal coordinate system of the X axis, the Y axis, and the Z axis is defined. As general-purpose CAD data, for example, there is STL (Standard Triangulated Language) data. The STL data includes, for each part, element information indicating a triangular element for representing the shape of the part, and vertex information indicating a vertex included in the triangular element. The element information is represented by, for example, normal information and vertex information for each element. The vertex information is, for example, vertex coordinate values (x coordinate value, y coordinate value, z coordinate value).

  Further, in order to perform numerical analysis such as the finite element method, a model for analysis obtained by dividing a three-dimensional model represented by STL data into a plurality of small regions by mesh generation is created. Since the shape of the small region is, for example, a tetrahedron, the small region is referred to as a tetrahedral element. The model for analysis is called an analysis model.

  When the CAD data includes information on the curved surface of the model, the contact surfaces of a plurality of parts included in the three-dimensional model can be determined based on the curved surface information. However, when the CAD data does not include information on the curved surface of the model like the general-purpose STL data described above, it is difficult to accurately determine the contact surfaces of a plurality of parts.

  For example, the structure is modeled by modeling for each part and combining the modeled parts. In addition, the size of each element may be different for each part. For this reason, even if it is a part used as the contact surface of several components in fact, the elements which represent different components are not necessarily in contact with the surface. An example in which these elements are not in contact with each other is shown in FIG.

  In addition, when the elements serving as contact surfaces of a plurality of parts do not match in the CAD data, some of the plurality of analysis models created for each part based on the CAD data may interfere with each other. Interference means that a plurality of analysis models overlap. Tetrahedral elements included in different analysis models may overlap. The fact that tetrahedral elements overlap means that a plurality of different tetrahedral elements are provided at the same position. The fact that tetrahedral elements overlap is also referred to as interference. An example of interference of tetrahedral elements is shown in FIG.

  Conventionally, when there are interferences in a plurality of analysis models, the designer visually determines the presence or absence of contact between the analysis models based on, for example, an allowable value for determining the presence or absence of contact. Then, for example, the designer corrects the analysis model for the portion determined to be in contact. However, when the model data of the analysis model is large, it is difficult to determine this allowable value because the size varies depending on individual parts.

  Therefore, in the present embodiment, when each part is represented by a triangular element, the contact determination device 100 includes a normal line of one element of the first part and a plane including one element of the second part. It is determined whether or not the two elements are in contact with each other according to the distance between the two elements. Thereby, the contact determination apparatus 100 can determine whether two elements are the contact surfaces of each component. Therefore, the contact determination device 100 can automatically and accurately specify the contact surface of each component in the CAD data representing each component as a triangular element.

  Users such as numerical analysis analysts and analysis model designers know the contact surface between two parts, so before creating the analysis model, change the STL data to match the STL data triangles on the contact surface. Can be modified. Therefore, interference of tetrahedral elements between different analysis models can be suppressed.

  The contact determination device 100 acquires data of a three-dimensional model including the first part and the second part. A three-dimensional model is a model of a structure. The first part and the second part are models of the parts, respectively. The data of the three-dimensional model is, for example, CAD data 101 such as the above-described STL data.

  Next, the contact determination apparatus 100 is based on the normal line of the first element e1 among the elements representing the first part and the plane including the second element e2 among the elements representing the second part. Thus, the first distance between the first element e1 and the second element e2 is specified. The shape of the element is, for example, a triangle. The first distance is, for example, the first intersection of the normal line of the first element e1 and the plane including the second element e2 and the normal line of the first element e1 and the first element e1. The first distance from the intersection of two. In the example of FIG. 1, the second intersection is, for example, the center of gravity a of the first element e1. The first intersection point is an intersection point p1 between the normal passing through the center of gravity a of the first element e1 and the plane including the second element e2. And the contact determination apparatus 100 specifies the 1st distance d1 of a 1st intersection and a 2nd intersection.

  Next, the contact determination device 100 determines whether or not the first element e1 and the second element e2 are in contact with each other according to the first distance d1. Specifically, the contact determination device 100 determines, for example, that the first element e1 and the second element e2 are not in contact when the first distance is greater than or equal to the first threshold, and the first distance Is less than the first threshold value, it is determined that the first element e1 and the second element e2 are in contact with each other. The first threshold here may be set by the user and is not particularly limited.

  Further, the contact determination device 100 determines the second distance d2 between the first element e1 and the second element e2 based on the normal line of the second element e2 and the plane including the first element e1. Is identified. Specifically, the second distance d2 includes the first intersection of the normal line of the second element e2 and the plane including the first element e1, and the normal line of the second element e2 and the second element e2. And the second intersection point. The second intersection point here is the center of gravity b of the second element e2. The first intersection point is an intersection point p2 between a normal line passing through the center of gravity b of the second element e2 and a plane including the first element e1.

  And the contact determination apparatus 100 determines whether the 1st element e1 and the 2nd element e2 are contacting according to the 2nd distance d2. Specifically, for example, when the second distance is equal to or greater than the second threshold, the contact determination device 100 determines that the first element e1 and the second element e2 are not in contact, and the second distance Is less than the second threshold value, it is determined that the first element e1 and the second element e2 are in contact with each other. The second threshold value here may be the same as the first threshold value described above, and is not particularly limited.

  As described above, the contact determination may be performed based on either the first distance d1 or the second distance d2, or the contact determination may be performed based on both the first distance d1 and the second distance d2. It may be broken. When the contact determination is performed by both of them, the contact determination apparatus 100 determines that the first element e1 and the first element e1 when the first distance d1 is less than the first threshold and the second distance is less than the second threshold. It determines with the 2nd element e2 contacting. In addition, the contact determination device 100 determines whether the first element e1 is the first element e1 when at least one of the first distance d1 is equal to or greater than the first threshold and the second distance d2 is equal to or greater than the second threshold. It determines with the 2nd element e2 not contacting.

  As a result, the contact determination device 100 automatically detects contact surfaces of different parts even if the CAD data 101 represents parts by triangular elements, such as general-purpose STL data that does not have curved surface information. Can be determined.

  FIG. 2 is an explanatory diagram illustrating an example of a three-dimensional model including a plurality of parts. In FIG. 2, the three-dimensional model 200 includes a first part 201 and a second part 202. In FIG. 2, a first part 201 and a second part 202 are models whose shapes are represented by a plurality of triangles, respectively. As shown in FIG. 7 described later, the first component 201 and the second component 202 have a thickness. For this reason, the second component 202 has such a shape that a part of the rectangular parallelepiped is missing. The first component 201 is shaped like a wheel. In the three-dimensional model 200, the first component 201 is in a state where the second component 202 is fitted in the recess. For this reason, since the first component 201 is fitted in the second component 202, the first component 201 and the second component 202 have a portion that becomes a contact surface in the three-dimensional model 200.

  However, the size of each element of the first component 201 is different from the size of each element of the second component 202, as shown in the enlarged example of the contact surface of the plurality of components. Actually, even in a portion that becomes a contact surface of a plurality of parts, elements representing different parts are not necessarily in contact with each other on the surface. The fact that the elements are in contact with each other means that the elements are matched. The fact that the elements match each other indicates that the positions of all the vertices included in the two elements representing different parts are the same. One factor that causes the size of elements to differ between different parts is that each part is modeled. For example, modeling is performed for each part, even if it is a single structure, when the same part is used many times, it can be used for modeling the part once, or the design of the part can be changed. This is because it is easy to design that it is not necessary to change the entire structure when it occurs.

  FIG. 3 is an explanatory diagram illustrating an example of an analysis model obtained by mesh generation from a three-dimensional model. The analysis model 300 is obtained by generating a tetrahedral mesh for the three-dimensional model 200. Specifically, the analysis model 300 is obtained by generating a tetrahedral mesh for each of the first component 201 and the second component 202. The analysis model 300 includes a first analysis model 301 generated with a mesh for the first component 201 and a second analysis model 302 generated with a mesh for the second component 202.

  If the elements do not match on the contact surface between the first component 201 and the second component 202 as shown in FIG. 2, the analysis model 300 is included in the first analysis model 301 as shown in FIG. Interference occurs between the tetrahedral element and the tetrahedral element included in the first analysis model 301. In FIG. 3, for example, at a point c, the tetrahedron element me1 included in the first analysis model 301 and the tetrahedron element me2 included in the second analysis model 302 interfere with each other.

  In the present embodiment, the contact determination device 100 can suppress the occurrence of interference in the analysis model by matching the contact surfaces between different models in the CAD data 101.

(Hardware configuration example of contact determination device 100)
FIG. 4 is an explanatory diagram illustrating a hardware configuration example of the contact determination device 100. The contact determination apparatus 100 includes a CPU (Central Processing Unit) 401, a ROM (Read Only Memory) 402, a RAM (Random Access Memory) 403, a disk drive 404, and a disk 405. The contact determination device 100 includes an I / F (Inter / Face) 406, a keyboard 407, a mouse 408, and a display 409. Further, the CPU 401, the ROM 402, the RAM 403, the disk drive 404, the I / F 406, the keyboard 407, the mouse 408, and the display 409 are connected by a bus 400, respectively.

  Here, the CPU 401 governs overall control of the contact determination device 100. The ROM 402 stores programs such as a boot program. The RAM 403 is used as a work area for the CPU 401. The disk drive 404 controls reading / writing of data with respect to the disk 405 according to the control of the CPU 401. The disk 405 stores data written under the control of the disk drive 404. Examples of the disk 405 include a magnetic disk and an optical disk.

  The I / F 406 is connected to a network 410 such as a LAN (Local Area Network), a WAN (Wide Area Network), and the Internet through a communication line, and is connected to other devices via the network 410. The I / F 406 controls an internal interface with the network 410 and controls input / output of data from an external device. For example, a modem or a LAN adapter may be employed as the I / F 406.

  A keyboard 407 and a mouse 408 are interfaces that accept input of various data in accordance with user operations. A display 409 is an interface that outputs data in accordance with an instruction from the CPU 401.

  Although not shown, the contact determination device 100 may be provided with an input device that captures images and moving images from a camera and an input device that captures audio from a microphone. Although not shown, the contact determination device 100 may be provided with an output device such as a printer.

  In the present embodiment, a personal computer is used as an example of the hardware configuration of the contact determination device 100. However, the present invention is not limited to this, and a server or the like may be used. When the contact determination device 100 is a server, the contact determination device 100 may be connected to the device operable by the user, the display 409, and the like via the network 410.

(Example of data format of CAD data 101)
FIG. 5 is an explanatory diagram showing a data format example of the CAD data 101. As an example of the data format of the CAD data 101, a storage example of the acquired CAD data 101 will be described using the data format of the STL data as an example. The CAD data 101 includes, for each element representing a part, an element normal and coordinates of three vertices constituting the element.

  Here, the CAD data 101 has triangle information representing the surface shape of the component, but does not have triangle information representing the internal shape of the component. In the STL data, elements and vertices are managed for each part. In STL data, when vertices are provided at the same position in different parts, the coordinate values of the three axes are the same and are treated as different vertices. In the present embodiment, for easy understanding, the vertex of the element included in the first component 201 and the vertex of the element included in the second component 202 set with the same coordinate value as this vertex are defined. May be treated as the same vertex.

(Functional configuration example of the contact determination device 100)
FIG. 6 is a block diagram illustrating a functional configuration example of the contact determination device 100. The contact determination apparatus 100 includes an acquisition unit 601, a first calculation unit 602, a second calculation unit 603, a third calculation unit 604, a determination unit 605, a generation unit 606, and an output unit 607. The processing of the control unit 600 from the acquisition unit 601 to the output unit 607 is coded in a program stored in a storage device such as the ROM 402, the RAM 403, and the disk 405 that can be accessed by the CPU 401 shown in FIG. Then, the CPU 401 reads the program from the storage device and executes the process coded in the program. Thereby, the process of the control part 600 is implement | achieved.

  For example, the acquisition unit 601 acquires the CAD data 101 of the three-dimensional model 200 including the first component 201 and the second component 202. Specifically, the acquisition unit 601 may acquire the CAD data 101 from another device via the network 410. Alternatively, the acquisition unit 601 may acquire the CAD data 101 from a storage device such as the ROM 402, the RAM 403, and the disk 405. Alternatively, the acquisition unit 601 may acquire the CAD data 101 by being input via an input device such as a mouse 408 or a keyboard 407. In order to facilitate understanding, the three-dimensional model 200 will be described using an example having two parts as shown in FIG. 2, but may have three or more parts.

  FIG. 7 is a perspective view of the first component 201 and the second component 202. The acquired CAD data 101 includes first component information 701 indicating the first component 201 and second component information 702 indicating the second component 202. The first component information 701 includes element information of an element representing the first component 201 and vertex information of vertices included in the element. The second part information 702 includes element information of an element representing the second part 202 and vertex information of vertices included in the element.

  The first component 201 expressed by the first component information 701 and the second component 202 expressed by the second component information 702 each have a thickness. In the three-dimensional model 200 shown in FIG. 2, the first part 201 is fitted to the second part 202, but in FIG. 7, the first part 201 and the second part 202 are shown for ease of understanding. The part that becomes the contact surface with is shown.

  Next, processing for determining whether or not the contact surface is present will be described. Here, three calculation examples of the criterion for determining whether or not the contact surface is used by using the first calculation unit 602 to the third calculation unit 604 will be given. Each calculation example will be described with reference to FIG.

  FIG. 8 is an explanatory diagram illustrating an example of a criterion for determining whether or not the contact surface. First, the first calculation unit 602 will be described. The first calculation unit 602 includes, for example, a normal line n1 of the first element e1 among the elements representing the first part 201 and a second element e2 among the elements representing the second part 202. Based on the above, the first distance d1 between the first element e1 and the second element e2 is specified.

  Specifically, the first calculation unit 602, for example, selects any first element e1 from an element representing the first component 201 and any second element from an element representing the first component 201. Element e2 is selected. The first calculation unit 602 specifies a first intersection between the normal line n1 of the first element e1 and the plane including the second element e2. The first calculation unit 602 specifies the second intersection point of the first element e1 and the normal line n1 of the first element e1. The first intersection point is a point p1 where the line and the plane including the second element e2 intersect when a line is drawn from the second intersection point in the direction of the normal line n1 of the first element e1. The second intersection is the center of gravity a. The first calculation unit 602 calculates a first distance d1 between the first intersection (point p1) and the second intersection (center of gravity a).

  The determination unit 605 determines whether or not the first element e1 and the second element e2 are in contact with each other according to the first distance d1. For example, the determination unit 605 determines that the first element e1 and the second element e2 are not in contact when the first distance d1 is equal to or greater than the first threshold. For example, when the first distance d1 is less than the first threshold, the determination unit 605 determines that the first element e1 and the second element e2 are in contact with each other.

  The second calculation unit 603 calculates the second distance d2 between the first element e1 and the second element e2 based on the normal line n2 of the second element e2 and the plane including the first element e1. Is identified.

  Specifically, the second calculation unit 603, for example, selects any one of a plurality of elements expressing the first component 201 and one of a plurality of elements expressing the second component 202. And the second element e2. Then, the second calculation unit 603 specifies, for example, a first intersection between the normal line n2 of the selected second element e2 and the plane including the selected first element e1. The first intersection point is a point p2 where the line intersects the plane including the first element e1 when a line is drawn from the second intersection point in the direction of the normal line n2 of the second element e2. For example, the second calculation unit 603 identifies the second intersection point of the second element e2 and the normal line n2 of the second element e2. The second intersection point here is, for example, the center of gravity b of the second element e2. The second calculation unit 603 calculates a second distance d2 between the first intersection (point p2) and the second intersection (center of gravity b).

  The determination unit 605 determines whether or not the first element e1 and the second element e2 are in contact with each other according to the second distance d2. For example, the determination unit 605 determines that the first element e1 and the second element e2 are not in contact when the second distance d2 is equal to or greater than the second threshold. For example, when the second distance d2 is less than the second threshold, the determination unit 605 determines that the first element e1 and the second element e2 are in contact with each other.

  Next, the third calculation unit 604 calculates, for example, the intersection angle θ between the normal line n1 of the first element e1 and the normal line n2 of the second element e2. For example, the third calculation unit 604 selects any first element e1 from a plurality of elements representing the first part 201 and any second element from a plurality of elements representing the second part 202. e2 is selected. Then, the third calculation unit 604 calculates, for example, the intersection angle θ between the normal line n1 of the first element e1 and the normal line n2 of the second element e2.

  Here, since the first element e1 and the second element e2 are orthogonal to each other as the intersection angle θ is larger, the first element e1 and the second element e2 are not in contact with each other. become. Further, when the normal line n1 of the first element e1 and the normal line n2 of the second element e2 are parallel, the intersection angle θ between the first element e1 and the second element e2 is not calculated. In such a case, the first element e1 and the second element e2 face each other. The first element e1 and the second element e2 face each other as the intersection angle θ is smaller. For example, the closer the first distance d1 and / or the second distance d2 is and the smaller the intersection angle θ is, the higher the possibility that the first element e1 and the second element e2 are in contact with each other.

  Therefore, the determination unit 605 contacts the first element e1 and the second element e2 based on the first distance d1 and / or the second distance d2 and the presence or absence of the intersection angle θ or the intersection angle θ. It is determined whether or not.

  Here, an example will be described in which it is determined whether or not the first element e1 and the second element e2 are in contact with each other based on the first distance d1 and the second distance d2 and the intersection angle θ. . More specifically, the determination unit 605 determines that the first distance d1 is less than the first threshold, the second distance d2 is less than the second threshold, and the intersection angle θ is less than the third threshold. It is determined that the first element e1 and the second element e2 are in contact. The determination unit 605 includes at least one of the case where the first distance d1 is equal to or greater than the first threshold, the case where the second distance d2 is equal to or greater than the second threshold, and the case where the intersection angle θ is equal to or greater than the third threshold. In such a case, it is determined that the first element e1 and the second element e2 are not in contact with each other.

  The contact determination apparatus 100 can specify the contact surface with higher accuracy by using the three determination criteria of the first distance d1, the second distance d2, and the intersection angle θ.

  Here, with respect to the first component 201, the determination unit 605 is an element of an element determined to be in contact with one of the elements expressing the second component 202 among the elements expressing the first component 201. Information is stored as contact surface information. For the first part 201, the determination unit 605 obtains element information of elements that are not determined to be in contact with any of the elements that represent the second part 202 among the elements that represent the first part 201. Store as non-contact surface information.

  Further, the determination unit 605 includes, for the second component 202, element information of an element determined to be in contact with any one of the elements expressing the first component 201 among the elements expressing the second component 202. Is stored as contact surface information. The determination unit 605 obtains element information of an element that is not determined to be in contact with any of the elements expressing the first part 201 among the elements expressing the second part 202 with respect to the second part 202. Store as non-contact surface information.

  When the output unit 607 determines that the first element e1 and the second element e2 are in contact with each other, the element expressing the first part 201 and the element expressing the second part 202 are: The first element e1 and the second element e2 are output so as to be distinguishable. Examples of the output format include output to the display 409, transmission to an external device through the I / F 406, storage in a storage device such as the RAM 403 and the disk 405, and the like.

  FIG. 9 is an explanatory diagram illustrating an output example. The output unit 607 distinguishes, for example, an element determined to be in contact with any one of the elements representing the second part 202 among the elements representing the first part 201 and an element other than this element. Output as possible. In addition, the output unit 607 includes, for example, an element that is determined to be in contact with any one of the elements that express the first part 201 among the elements that express the second part 202, and an element other than this element Are output in a distinguishable manner.

  Specifically, the output unit 607 differs between an element determined to be in contact and an element not determined to be in contact, for example, when displaying each component on the display 409 by CAD. Display with color. Further, the output unit 607 highlights, for example, an element determined to be in contact. In FIG. 9, in the first component 201, elements that are determined to be in contact are hatched. In FIG. 9, in the second part 202, different hatching is given to an element determined to be in contact with an element determined to be not in contact.

  Further, the output unit 607 identifies, as a single contact surface, a series of elements that share vertices among the elements determined to be in contact with each other. Then, the output unit 607 may output the specified number of contact surfaces.

  An example method for searching for a series of elements is as follows. For example, the output unit 607 selects any one of the plurality of elements determined to be in contact with each other. Then, the output unit 607 detects an element sharing a vertex with the selected element from the plurality of elements determined to be in contact with the selected element. Then, the output unit 607 sets the selected element and the detected element as a series of elements. The output unit 607 further detects an element sharing a vertex with the detected element from elements other than the series of elements among the plurality of elements determined to be in contact. Then, the output unit 607 includes the newly detected element in a series of elements. In this way, a series of elements are searched.

  In FIG. 9, in the first component information 701, element information of all elements is classified into non-contact surface information 902 for the first component 201 and contact surface information 901 for the first component 201. Is done. Further, in the second part information 702, element information of all elements is classified into non-contact surface information 912 for the second part 202 and contact surface information 911 for the second part 202.

  Next, processing for matching elements on the contact surface between the first component 201 and the second component 202 will be described.

  Further, when it is determined that the first element e1 and the second element e2 are in contact with each other, the generation unit 606 generates an element that represents a new part corresponding to the first part 201. The generation unit 606 includes, among the elements representing the first component 201, a vertex different from the vertex included in the third element including the vertex included in the first element e1, and the second element e2. Based on this, an element representing this new part is generated. The elements expressing the new part are elements other than the first element e1 and the third element among the elements expressing the first part 201, the same element as the second element e2, a different vertex and the first element. And an element generated by a vertex included in the second element e2.

  Generating an element that expresses a new part actually means changing the CAD data 101. More specifically, in the present embodiment, the generation unit 606 creates a new part corresponding to the first part 201 by changing an element representing the first part 201. For this reason, the new part is also referred to as the first part 201. In the following description, the process of deleting or generating an element or a vertex means deleting the element information of the element or the vertex information of the vertex from the CAD data 101. Moreover, although the example which changes the element showing the 1st component 201 is given, it is not specifically limited about which element of the 1st component 201 and the 2nd component 202 is changed, for example, a user May be selected.

  Next, a detailed example of processing for matching the elements of the contact surface between the first component 201 and the second component 202 will be described with reference to FIGS.

  FIG. 10 is an explanatory diagram illustrating a specific example of a free edge. The generation unit 606, based on the contact surface information 901 for the first component 201, among the edges of the elements that are determined to be in contact, the edges that are not shared between the elements that are determined to be in contact A vertex of (also referred to as a first free edge fe1) is specified. Then, the generation unit 606 stores first vertex information 1011 of the identified first free edge fe1. Next, the generation unit 606 deletes the contact surface information 901 for the first component 201.

  Then, the generation unit 606 duplicates the contact surface information 911 regarding the second component 202. The generation unit 606 puts the copied contact surface information 1001 in the first part information 701. As a result, the element representing the new part corresponding to the first part 201 can include the same element as the second element e2 determined to be in contact.

  Based on the copied contact surface information 1001, the generation unit 606 generates an edge (second free edge) that is not shared among elements determined to be contacted among edges of elements determined to be contacted. (also referred to as fe2)). Then, the generation unit 606 stores the second vertex information 1012 on the vertexes of the identified second free edge fe2.

  FIG. 11 is an explanatory diagram illustrating a specific example of an element sharing a vertex with the first free edge fe1. In FIG. 11, elements surrounded by the first free edge fe1 are elements indicated by the duplicated contact surface information 1001.

  The generation unit 606 identifies element information 1100 of an element including a vertex indicated by the first vertex information 1011 from the non-contact surface information 902 regarding the first component 201. That is, the generation unit 606 specifies an element that shares a vertex with the first free edge fe1. Then, the generation unit 606 identifies third vertex information 1101 of a vertex different from the vertex indicated by the first vertex information 1011 among the vertices included in the element indicated by the element information 1100.

  FIG. 12 is an explanatory diagram illustrating an example of deleting an element sharing a vertex with the first free edge fe1. The generation unit 606 deletes the element information 1100. As a result, the element having the same vertex as that of the first free edge fe1 is deleted.

  FIG. 13 is an explanatory diagram illustrating an example in which a new element is generated. The generation unit 606 generates a new element for the first component 201 based on the vertices included in the second vertex information 1012 and the vertices included in the third vertex information 1101. Thereby, an element representing a new part corresponding to the first part 201 is generated.

  Then, the output unit 607 outputs the three-dimensional model 200 including the first component 201 and the second component 202 expressed by the newly generated element.

  Further, the present invention is not limited to the above-described embodiment, and various modifications can be made. In the embodiment, the generation unit 606 performs the process of matching the element of the contact surface of the first component 201 with the element of the contact surface of the second component 202, but the present invention is not limited to this. For example, the user may be able to select which part of the contact surface of the first part 201 and the second part 202 matches the element of the contact surface of the other part. For example, the user may select which component of the contact surface of which component is matched according to the display result of the contact surface.

(Example of processing procedure performed by contact determination device 100)
FIG. 14 is a flowchart illustrating an example of a processing procedure performed by the contact determination device 100. First, the contact determination apparatus 100 acquires CAD data 101 (step S1401). The contact determination device 100 performs a contact surface determination process (step S1402). Next, the contact determination apparatus 100 performs an element generation process (step S1403).

  Next, the contact determination device 100 displays the elements that are the contact surfaces and the elements that are not the contact surfaces in a distinguishable manner based on the contact surface information (1001, 911) and the non-contact surface information (902, 912). Then (step S1404), a series of processing is terminated.

  Moreover, the contact determination apparatus 100 may perform the process which displays so that the element which is a contact surface and the element which is not a contact surface can be distinguished between step S1402 and step S1403.

  FIG. 15 is a flowchart showing a detailed description of the contact surface determination process shown in FIG. The contact determination device 100 determines whether or not there is an unprocessed first element among the elements representing the first component 201 (step S1501). Next, when it is determined that there is an unprocessed first element (step S1501: Yes), the contact determination device 100 selects an unprocessed first element (step S1502).

  The contact determination device 100 determines whether there is an unprocessed second element in the selected first element among the elements representing the second component 202 (step S1503). When it is determined that there is an unprocessed second element (step S1503: Yes), the contact determination device 100 selects an unprocessed second element (step S1504). Next, the contact determination apparatus 100 calculates an intersection angle θ between the normal line of the selected first element and the normal line of the selected second element (step S1505).

  Next, the contact determination apparatus 100 determines whether or not the intersection angle θ is equal to or greater than a third threshold (step S1506). When it is determined that the intersection angle θ is equal to or greater than the third threshold (step S1506: Yes), the contact determination device 100 returns to step S1503. When it is determined that the intersection angle θ is not greater than or equal to the third threshold (step S1506: No), the contact determination device 100 calculates the first distance d1 (step S1507).

  The contact determination device 100 determines whether or not the first distance d1 is greater than or equal to the first threshold (step S1508). When it is determined that the first distance d1 is greater than or equal to the first threshold (step S1508: Yes), the contact determination device 100 returns to step S1503. When it is determined that the first distance d1 is not equal to or greater than the first threshold (step S1508: No), the contact determination device 100 calculates the second distance d2 (step S1509). The contact determination device 100 determines whether or not the second distance d2 is greater than or equal to the second threshold (step S1510).

  When it is determined that the second distance d2 is greater than or equal to the second threshold (step S1510: Yes), the contact determination device 100 returns to step S1503. When it is determined that the second distance d2 is not equal to or greater than the second threshold (step S1510: No), the contact determination device 100 sets the element information indicating the first element as the contact surface information 901 for the first component 201. Store (step S1511). Next, the contact determination apparatus 100 stores element information indicating the second element in the contact surface information 911 for the second component 202 (step S1512), and returns to step S1501.

  When it is determined in step S1503 that there is no unprocessed second element (step S1503: No), the contact determination device 100 displays element information indicating the first element as a non-contact surface for the first component 201. The information is stored in the information 902 (step S1513) and the process returns to step S1501. Next, when it is determined that there is no unprocessed first element (step S1501: No), the contact determination device 100 selects a second element that is not included in the contact surface information 911 for the second component 202. The element information to be shown is stored in the non-contact surface information 912 for the second component 202 (step S1514), and the series of processes is terminated.

  As shown in FIG. 15, the calculation process and the determination process for the first distance d1, the second distance d2, and the intersection angle θ are performed in the order of the intersection angle θ, the first distance d1, and the second distance d2. Not limited to this, various changes may be made and parallel processing may be used, and there is no particular limitation.

  FIG. 16 is a flowchart showing a detailed description of the element generation processing shown in FIG. The contact determination device 100 stores the first vertex information 1011 of the vertex of the first free edge fe1 among the edges of the elements indicated by the element information included in the contact surface information 901 for the first component 201 (step S1601). .

  Next, the contact determination apparatus 100 deletes the contact surface information 901 for the first component 201 (step S1602). Thereby, the element of the contact surface of the first component 202 is deleted from the element representing the first component 201.

  Then, the contact determination device 100 duplicates the contact surface information 911 for the second component 202 and stores it as the contact surface information 901 for the first component 201 (step S1603). Next, the contact determination apparatus 100 stores the second vertex information 1012 on the second free edge fe2 among the edges of the elements indicated by the element information included in the contact surface information 901 for the first component 201 (step) S1604).

  Next, the contact determination apparatus 100 identifies element information 1100 indicating an element including a vertex indicated by the first vertex information 1011 from the non-contact surface information 902 for the first component 201 (step S1605). Thereby, the triangle including the vertex of the first free edge fe1 is specified from the non-contact surface information 902. The contact determination apparatus 100 specifies vertices other than the vertices indicated by the first vertex information 1011 among the vertices of the elements indicated by the specified element information 1100, and stores the third vertex information 1101 (step S1606).

  Next, the contact determination device 100 deletes the element information 1100 from the non-contact surface information 902 for the first component 201 (step S1607). Next, the contact determination apparatus 100 reconstructs a triangular element based on the third vertex information 1101 and the second vertex information 1012 (step S1608), and ends a series of processes. In step S1608, element information 1200 of the element is generated. In step S1608, a new element is generated in place of the element indicated by the deleted element information 1100.

  As described above, the contact determination device 100 is based on the normal of one element of the first part and the plane including one element of the second part when each part is represented by a triangular element. Whether or not the two elements are in contact is determined according to the distance between the two elements. Thereby, the contact determination apparatus 100 can determine whether or not the two elements are contact surfaces of each component depending on whether or not the two elements are close to each other. Therefore, the contact determination apparatus 100 can automatically and accurately specify the contact surface of each component even if it is general-purpose CAD data such as STL data. Thus, since it is not necessary to use paid CAD data having curved surface information, the analysis can be made inexpensive.

  Further, when the contact determination device 100 determines that the first element and the second element are in contact with each other, the first element and the second element among the first part and the second part Are output in a distinguishable manner. Thereby, the contact determination apparatus 100 can show the contact surface of components easily.

  Further, the contact determination device 100 determines the distance between the first element and the second element as a first intersection between the normal of the first element and the plane including the second element, and the first element. The distance from the second intersection with the normal of the first element is calculated.

  Further, the contact determination device 100 determines the first distance based on the normal line of the second element and the plane including the first element according to the second distance between the first element and the second element. It is determined whether or not the first element and the second element are in contact with each other. Thereby, when the first element is viewed from the second element, it is determined whether or not the first element and the second element are contact surfaces.

  Further, for example, it is conceivable that the element surfaces face each other on the contact surface. Therefore, the contact determination device 100 makes contact between the first element and the second element according to the intersection angle between the normal line of the first element and the normal line of the second element and the first distance. It is determined whether or not. Thereby, the contact determination device 100 is configured such that when the first element and the second element are close to each other and the first element and the second element face each other, the first element and the second element Can be determined to be a contact surface. Therefore, the contact determination device 100 can specify the contact surface of the component with higher accuracy.

  Further, the contact determination device 100 includes, among elements representing the first part, a vertex different from the vertex included in the third element including the vertex included in the first element, and a second element. Based on this, an element representing a new part corresponding to the first part is generated. Thereby, the contact determination apparatus 100 can make the element of a 1st component and the element of a 2nd component correspond in the part used as a contact surface. Therefore, the contact determination apparatus 100 can suppress interference of tetrahedral elements in the analysis model.

  The contact determination method described in this embodiment can be realized by executing a contact determination program prepared in advance on a computer such as a personal computer or a workstation. The contact determination program is recorded on a computer-readable recording medium such as a magnetic disk, an optical disk, or a USB (Universal Serial Bus) flash memory, and is executed by being read from the recording medium by the computer. Further, the contact determination program may be distributed via a network such as the Internet.

  In addition, the contact determination device 100 is a PLD (Programmable Gate Array) such as a standard cell or a specific application IC (hereinafter simply referred to as “ASIC”) such as a structured ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). It can also be realized by Device). Specifically, for example, the function of the contact determination device described above is defined by a HDL (Hardware Description Language) description, and the HDL description is logically synthesized and given to the ASIC or PLD to manufacture the contact determination device 100. be able to.

  The following additional notes are disclosed with respect to the embodiment described above.

(Supplementary note 1) Acquire data of a three-dimensional model including a first part and a second part,
Based on the normal of the first element among the elements representing the first part and the plane including the second element among the elements representing the second part, the first element and the Identify the distance between the second element,
Determining whether the first element and the second element are in contact according to the distance;
A contact determination program for causing a computer to execute processing.

(Supplementary Note 2) When it is determined that the first element and the second element are in contact with each other, the element representing the first part and the element representing the second part are Outputting the first element and the second element in a distinguishable manner;
The contact determination program according to Supplementary Note 1, wherein

(Supplementary Note 3) The distance is the first intersection of the normal line of the first element and the plane including the second element, and the normal line of the first element and the normal line of the first element. The distance from the intersection of
The contact determination program according to Supplementary Note 1, wherein

(Supplementary Note 4) Based on a normal line of the second element and a plane including the first element, a second distance between the first element and the second element is specified,
The determination as to whether or not the first element and the second element are in contact is determined according to the second distance.
The contact determination program according to Supplementary Note 1, wherein

(Supplementary Note 5) Whether or not the first element and the second element are in contact with each other is determined by whether or not there is an intersection angle between the normal line of the first element and the normal line of the second element, or It is determined according to the size of the intersection angle and the distance.
The contact determination program according to any one of supplementary notes 1 to 4, characterized in that:

(Additional remark 6) When the said 1st element and the said 2nd element are contacting, the 3rd element containing the vertex contained in the said 1st element among the elements expressing the said 1st component Generating an element representing a new part corresponding to the first part based on the vertex different from the vertex included in the second element and the second element;
The contact determination program according to any one of appendices 1 to 5, characterized in that:

(Additional remark 7) The element expressing the new part is the same element as the second element and the elements other than the first element and the third element among the elements expressing the first part And an element generated by the different vertex and the vertex included in the second element. 7. The contact determination program according to appendix 6, wherein:

(Supplementary Note 8) Acquire data of a three-dimensional model including the first part and the second part,
Based on the normal of the first element among the elements representing the first part and the plane including the second element among the elements representing the second part, the first element and the Identify the distance between the second element,
Determining whether the first element and the second element are in contact according to the distance;
A contact determination method, wherein a computer executes a process.

(Supplementary Note 9) Acquire data of a three-dimensional model including the first part and the second part,
Based on the normal of the first element among the elements representing the first part and the plane including the second element among the elements representing the second part, the first element and the Identify the distance between the second element,
Determining whether the first element and the second element are in contact according to the distance;
A contact determination device having a control unit.

DESCRIPTION OF SYMBOLS 100 Contact determination apparatus 101 CAD data 200 3D model 201 1st part 202 2nd part 300 Analysis model 301 1st analysis model 302 2nd analysis model 600 Control part 601 Acquisition part 602 1st calculation part 603 2nd Calculation unit 604 Third calculation unit 605 Determination unit 606 Generation unit 607 Output unit 701 First component information 702 Second component information 901, 911, 1001 Contact surface information 902, 912 Non-contact surface information 1011 First vertex information 1012 Second vertex Information 1100, 1200 Element information 1101 Third vertex information

Claims (8)

Acquiring data of a three-dimensional model including the first part and the second part;
Based on the normal of the first element among the elements representing the first part and the plane including the second element among the elements representing the second part, the first element and the Identify the distance between the second element,
Determining whether the first element and the second element are in contact according to the distance;
A contact determination program for causing a computer to execute processing. When it is determined that the first element and the second element are in contact with each other, the first element among the element expressing the first part and the element expressing the second part And the second element are output in a distinguishable manner,
The contact determination program according to claim 1, wherein: The distance is a first intersection point between a normal line of the first element and a plane including the second element, and a second intersection point between the first element and the normal line of the first element. Is the distance to
The contact determination program according to claim 1, wherein: Determining a second distance between the first element and the second element based on a normal of the second element and a plane including the first element;
The determination as to whether or not the first element and the second element are in contact is determined according to the second distance.
The contact determination program according to claim 1, wherein: Whether or not the first element and the second element are in contact with each other is determined by the presence or absence of the intersection angle between the normal line of the first element and the normal line of the second element or the magnitude of the intersection angle. And is determined according to the distance,
The contact determination program according to claim 1, wherein the contact determination program is any one of claims 1 to 4. When the first element and the second element are in contact with each other, the element included in the third element including the vertex included in the first element among the elements expressing the first part Generating an element representing a new part corresponding to the first part based on a vertex different from the vertex and the second element;
The contact determination program according to any one of claims 1 to 5, wherein: Acquiring data of a three-dimensional model including the first part and the second part;
Based on the normal of the first element among the elements representing the first part and the plane including the second element among the elements representing the second part, the first element and the Identify the distance between the second element,
Determining whether the first element and the second element are in contact according to the distance;
A contact determination method, wherein a computer executes a process. Acquiring data of a three-dimensional model including the first part and the second part;
Based on the normal of the first element among the elements representing the first part and the plane including the second element among the elements representing the second part, the first element and the Identify the distance between the second element,
Determining whether the first element and the second element are in contact according to the distance;
A contact determination device having a control unit.

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