Patent Publication Number: US-2019179981-A1

Title: Structural analysis simulation method and information processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2017-235656, filed on Dec. 8, 2017, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiments discussed herein are related to a structural analysis simulation method and an information processing apparatus. 
     BACKGROUND 
     There are known techniques for conducting a structural analysis of a design object using a computer based on design data of the object, to thereby evaluate the performance of the object in terms of strength, vibration, heat, and the like. 
     When a structural analysis is performed, conditions for a structural analysis simulation (for example, boundary conditions) are set for regions of an object represented by design data. Subsequently, finite elements are created by element division according to the shape of the object and the purpose of the analysis, and then a simulation is run. Results obtained from the simulation are presented on a display device. 
     Conventionally, conditions for a simulation are set in association with identification numbers assigned, within an object to be analyzed, to individual regions differentiated by shape, such as points, edges, and surfaces. Such identification numbers are hereinafter referred to as “shape IDs”. For example, within the object, a surface is assigned SurfaceID_ 1 , a different surface is assigned SurfaceID_ 2 , an edge is assigned EdgeID_ 1 , and a different edge is assigned EdgeID_ 2 . Then, conditions are set in association with these individual shape IDs. Thus, holding the conditions in association with the individual shape IDs reduces the need of resetting conditions when structural analyses are repeatedly performed on the same object. 
     See, for example, Japanese Laid-open Patent Publication No. 11-120383. 
     However, the conventional technique leaves the problem of possibly being accompanied by changes in the shape IDs defined in design data when a design change has caused changes in the shape of the object (for example, when the number of points and/or surfaces has changed). In the case where changes have been made in the shape IDs, unintentional analysis conditions may be set for regions of the object, which is likely to cause a structural analysis to yield erroneous results. 
     SUMMARY 
     According to an aspect, there is provided a non-transitory computer-readable storage medium storing a computer program that causes a computer to execute a process including: setting a condition for running a structural analysis simulation of an object, in association with first design data corresponding to the object; identifying, when the first design data is updated according to a design change of the object, a corresponding relationship between regions each included in the first design data and second design data, which corresponds to the object modified with the design change, based on coordinate information included in the first design data and coordinate information included in the second design data; and setting, based on the corresponding relationship, the condition in association with the second design data and running the structural analysis simulation of the modified object. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates an example of an information processor and structural analysis simulation method according to a first embodiment; 
         FIG. 2  is a block diagram illustrating an example of hardware of an information processor according to a second embodiment; 
         FIG. 3  illustrates a block diagram illustrating an example of functions provided in the information processor; 
         FIG. 4  is a flowchart illustrating an example of a process carried out by the information processor; 
         FIG. 5  illustrates a setting example of analysis conditions; 
         FIG. 6  is a flowchart illustrating an example of a process of identifying a corresponding relationship between regions each included in pre-update and post-update design datasets and a process of setting each analysis condition in association with the post-update design dataset; 
         FIG. 7  illustrates an example in which a plurality of edges that matches an edge with an analysis condition set is included in the post-update design dataset; 
         FIG. 8  illustrates an example of Method 2 for tentatively determining a matching edge or edges; 
         FIG. 9  illustrates an example of Method 2 for tentatively determining a matching surface or surfaces; and 
         FIG. 10  illustrates an example of Method 2 for tentatively determining a matching solid or solids. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Several embodiments will be described below with reference to the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
     (a) First Embodiment 
       FIG. 1  illustrates an example of an information processor and structural analysis simulation method according to a first embodiment. 
     An information processor  10  of the first embodiment runs a structural analysis simulation of an object based on a design dataset of the object. Note that the information processor  10  may be a client computer or server computer. 
     The information processor  10  includes a storing unit  11  and a processing unit  12 . 
     The storing unit  11  may be a volatile memory device such as random access memory (RAM), or a non-volatile memory device such as a hard disk drive (HDD) or flash memory. 
     The storing unit  11  stores therein design datasets  11   a  and  11   b  and analysis condition setting information  11   c.    
     The design datasets  11   a  and  11   b  are pre-update and post-update design datasets associated with a design change of an object. Specifically, the design dataset  11   a  is the pre-update design dataset and the design dataset  11   b  is the post-update design dataset. The design datasets  11   a  and  11   b  may be individually generated based on inputs provided by the user when the information processor  10  implements software for creating a design dataset and allows the user to provide the inputs. Alternatively, the design datasets  11   a  and  11   b  may be acquired, for example, from an apparatus external to the information processor  10  via a network. 
     The analysis condition setting information  11   c  is information on conditions for conducting a structural analysis (hereinafter referred to as “analysis conditions”), set by the processing unit  12  in association with the individual design datasets  11   a  and  11   b . Examples of such analysis conditions include boundary conditions and conditions for materials of regions included in the object. Examples of the boundary conditions include conditions on in which direction a given region within the object is fixed and in which direction it is free to move (constraint conditions) and conditions on a given region within the object experiences forces in which direction and with what magnitude (loading conditions). 
     The processing unit  12  is a processor, such as a central processing unit (CPU) and a digital signal processor (DSP). Note however that the processing unit  12  may include an electronic circuit designed for specific use, for example, an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). The processor executes programs stored in a memory device such as RAM. For example, the processor executes a structural analysis simulation program. The term “multiprocessor”, or simply “processor”, is sometimes used here to refer to a set of multiple processors. 
     The processing unit  12  sets analysis conditions to be used in a structural analysis simulation of an object, in association with the design dataset  11   a  corresponding to the object. For example, in setting the analysis conditions, a three-dimensional (3D) image of the object is presented on a screen of a display device (not illustrated) connected to the information processor  10 . Then, the processing unit  12  receives an analysis condition specified by the user for each desired region (which is not only a surface or solid but also a point or edge in the following description) within the object, and sets the analysis condition in association with coordinate information representing the region, included in the design dataset  11   a . Information obtained in this manner is stored in the storing unit  11  to form the analysis condition setting information  11   c.    
     When the design dataset  11   a  is updated according to a change in the design of the object, the processing unit  12  identifies a corresponding relationship between regions each included in the pre-update and post-update design datasets  11   a  and  11   b , based on coordinate information included in the pre-update design dataset  11   a  and coordinate information included in the post-update design dataset  11   b . Then, based on the identified corresponding relationship, the processing unit  12  sets the above-mentioned analysis condition in association with the post-update design dataset  11   b , and runs a structural analysis simulation of the object modified by the design change. The processing unit  12  may cause the display device (not illustrated) to present results of the structural analysis simulation on its screen. 
       FIG. 1  depicts an example of a structural analysis simulation method employed by the information processor  10  of the first embodiment. 
     For a surface  15   a , which is a single region within an object  15 , a condition A is set as an analysis condition. Assume that due to a design change made to the object  15 , an object  16  with an illustrated shape is formed. Since the modified object  16  includes regions having the same configurations as those of the object  15  before the design change, it is preferable that individual analysis conditions set for the regions having the same configurations be carried over. For example, the surface  15   a  of the pre-change object  15  has the same configuration as a surface  16   a  of the post-change object  16 . The processing unit  12  then identifies a corresponding relationship between these regions (i.e., the surfaces  15   a  and  16   a ) based on coordinate information included in the individual pre-update and post-update design datasets  11   a  and  11   b.    
     For example, coordinate information  11   a   1  representing the surface  15   a , included in the design dataset  11   a , includes coordinate information representing edges  17   a ,  17   b ,  17   c , and  17   d  and coordinate information representing a representative point of the surface  15   a.    
     The coordinate information representing the edge  17   a  includes, for example, coordinate information representing end points  18   a  and  18   b  of the edge  17   a  and coordinate information representing a middle point  18   c  of the edge  17   a . The coordinate information representing the edge  17   b  includes, for example, coordinate information representing the end points  18   a  and  18   b  of the edge  17   b  and coordinate information representing a middle point  18   d  of the edge  17   b . The coordinate information representing the edge  17   c  includes, for example, coordinate information representing end points  18   e  and  18   f  of the edge  17   c  and coordinate information representing a middle point  18   g  of the edge  17   c . The coordinate information representing the edge  17   d  includes, for example, coordinate information representing the end points  18   e  and  18   f  of the edge  17   d  and coordinate information representing a middle point  18   h  of the edge  17   d.    
     A representative point  18   i  may lie apart from the surface  15   a . In the example of  FIG. 1 , the representative point  18   i  of the ring-shaped surface  15   a  is the center point of a circle formed by the edges  17   a  and  17   b.    
     The processing unit  12  searches the post-update design dataset  11   b  for a region with coordinate information corresponding to the coordinate information  11   a   1  representing the above-described surface  15   a . For example, the processing unit  12  determines, as the region with coordinate information corresponding to the coordinate information  11   a   1  of the surface  15   a , a region with coordinate information that exactly matches all the coordinate information representing the edges  17   a  to  17   d  and the representative point  18   i.    
     Suppose, for example, that the processing unit has detected, in the design dataset  11   b , coordinate information  11   a   2  that exactly matches the coordinate information  11   a   1 . That is, the processing unit  12  has identified the surface  16   a , which corresponds to the surface  15   a  on the pre-change object  15 . In this case, the processing unit  12  sets, in the design dataset  11   b , the same analysis condition assigned to the surface  15   a  (that is, the condition A) for the surface  16   a . Information on the analysis condition set in the design dataset  11   b  is recorded, for example, in the storing unit  11 . At this time, the processing unit  12  may update the analysis condition setting information  11   c , or leave the analysis condition setting information  11   c  corresponding to the pre-update design dataset  11   a.    
     Note that the processing unit  12  may tentatively determine the surface  16   a  as a region corresponding to the surface  15   a  even if the coordinate information  11   a   1  and the coordinate information  11   a   2  do not match exactly. In that case, the processing unit  12  may cause the display device (not illustrated) to present, on its screen, a note indicating that the surface  16   a  is a tentatively determined region, to thereby prompt the user to select whether to allow the analysis condition assigned to the surface  15   a  to be carried over to the surface  16   a.    
     As described above, the information processor  10  of the first embodiment sets each analysis condition in association with the post-update design dataset  11   b  based on a corresponding relationship between regions each included in the pre-update and post-update design datasets  11   a  and  11   b , identified from coordinate information included in the individual design datasets  11   a  and  11   b . This prevents unintentional analysis conditions from being set in association with the post-update design dataset  11   b , which could occur, for example, in associating each analysis condition with a shape ID, thus being able to avoid a structural analysis from yielding erroneous results. In addition, this technique reduces the need of resetting analysis conditions for the post-update design dataset  11   b  in a reanalysis after a design change. 
     Other than a design change, there are various causes for changes in shape IDs, such as a user operation on design data generation software (for example, an operation of editing design datasets of a plurality of objects at the same time). Even if changes are made in shape IDs due to such a cause, incorrect setting of analysis conditions is prevented because the information processor  10  sets each analysis condition in association with the post-update design dataset  11   b  based on a corresponding relationship between regions each included in the pre-update and post-update design datasets  11   a  and  11   b , identified from coordinate information included in the individual design datasets  11   a  and  11   b.    
     The information processor  10  also eliminates the need of holding shape IDs, which in turn eliminates the need of allocating memory space for the shape IDs. 
     (b) Second Embodiment 
     This part explains a second embodiment. 
       FIG. 2  is a block diagram illustrating an example of hardware of an information processor. 
     An information processor  20  includes a CPU  21 , a RAM  22 , a HDD  23 , an image signal processing unit  24 , an input signal processing unit  25 , a media reader  26 , and a communication interface  27 . These individual units are connected to a bus. 
     The CPU  21  is a processor including a computing circuit for carrying out program instructions. The CPU  21  reads out at least part of programs and data stored in the HDD  23 , loads them into the RAM  22 , and executes the loaded programs. Note that the CPU  21  may include two or more processor cores and the information processor  20  may include two or more processors, and processes to be described later may be executed in parallel using these processors or processor cores. The term “processor” may be used to refer to a set of processors (multiprocessor). 
     The RAM  22  is volatile semiconductor memory for temporarily storing therein programs to be executed by the CPU  21  and data to be used by the CPU  21  for its computation. Note that the information processor  20  may be provided with a different type of memory other than RAM, or may be provided with two or more memory devices. 
     The HDD  23  is a non-volatile memory device to store therein software programs, such as an operating system (OS), middleware, and application software, as well as various types of data. The programs include, for example, a structural analysis simulation program for causing the information processor  20  to run a structural analysis simulation. Note that the information processor  20  may be provided with a different type of memory device, such as flash memory or a solid state drive (SSD), or may be provided with two or more non-volatile memory devices. 
     The image signal processing unit  24  produces video images in accordance with drawing commands from the CPU  21  and displays them on a screen of a display  24   a  coupled to the information processor  20 . The display  24   a  may be any type of display, such as a cathode ray tube (CRT) display; a liquid crystal display (LCD); a plasma display panel (PDP); or an organic electro-luminescence (OEL) display. 
     The input signal processing unit  25  receives an input signal from an input device  25   a  connected to the information processor  20  and supplies the input signal to the CPU  21 . Various types of input devices may be used as the input device  25   a , for example, a pointing device, such as a mouse, a touch panel, a touch-pad, or a trackball; a keyboard; a remote controller; or a button switch. A plurality of types of input devices may be connected to the information processor  20 . 
     The media reader  26  is a reader for reading programs and data recorded in a storage medium  26   a . As the storage medium  26   a , any of the following may be used: a magnetic disk, an optical disk, a magneto-optical disk (MO), and a semiconductor memory. Examples of the magnetic disk are a flexible disk (FD) and a HDD. Examples of the optical disk are a compact disc (CD) and a digital versatile disc (DVD). 
     The media reader  26  copies programs and data read from the storage medium  26   a  to a different storage medium, for example, the RAM  22  or the HDD  23 . The read programs are executed, for example, by the CPU  21 . Note that the storage medium  26   a  may be a portable storage medium, and may be used to distribute the programs and data. The storage medium  26   a  and the HDD  23  are sometimes referred to as computer-readable storage media. 
     The communication interface  27  is connected to a network  27   a  and communicates with different information processors via the network  27   a . The communication interface  27  may be a wired communication interface connected via a cable to a communication device, such as a switch, or may be a wireless communication interface connected via a wireless link to a base station. 
     The information processor  20  described above may be a client computer or server computer. 
     Next described are functions of the information processor  20  and its processing procedure. 
       FIG. 3  illustrates a block diagram illustrating an example of functions provided in an information processor. 
     The information processor  20  includes an analysis condition setting unit  31 , a corresponding relationship identifying unit  32 , a simulation executing unit  33 , a display unit  34 , a design data storing unit  35 , an analysis condition information storing unit  36 , and a tentatively determined region storing unit  37 . The analysis condition setting unit  31 , the corresponding relationship identifying unit  32 , the simulation executing unit  33 , and the display unit  34  are implemented, for example, as modules of a program executed by the CPU  21 . The design data storing unit  35 , the analysis condition information storing unit  36 , and the tentatively determined region storing unit  37  are implemented using a storage area secured, for example, in the RAM  22  or the HDD  23 . 
     The analysis condition setting unit  31  sets each analysis condition in association with a design dataset of an object for a structural analysis. The analysis condition setting unit  31  also sets, based on a corresponding relationship between regions each included in pre-update and post-update design datasets, identified by the corresponding relationship identifying unit  32 , the analysis condition in the post-update design dataset. 
     When a design dataset of the object is updated according to a design change of the object, the corresponding relationship identifying unit  32  identifies, based on coordinate information included in the individual pre-update and post-update design datasets, a corresponding relationship between regions each included in the pre-update and post update design datasets. 
     The simulation executing unit  33  runs a structural analysis simulation of the object modified by the design change. 
     The display unit  34  controls the image signal processing unit  24  to present results of the structural analysis simulation on a screen of the display  24   a . In addition, the display unit  34  causes information about each region tentatively determined in a process described below to be presented on the screen of the display  24   a.    
     The design data storing unit  35  stores therein the pre-update and post-update design datasets associated with the design change of the object. 
     The analysis condition information storing unit stores therein information about analysis conditions set in association with each design dataset. 
     The tentatively determined region storing unit stores therein information about each region tentatively determined in a process described below. 
       FIG. 4  is a flowchart illustrating an example of a process carried out by an information processor. 
     (Step S 10 ) The analysis condition setting unit  31  reads a design dataset stored, for example, in the HDD  23 . 
     (Step S 11 ) The analysis condition setting unit  31  receives an input of an instruction signal indicating whether to conduct a new analysis or reanalysis of the structure of an object which corresponds to the read design dataset. The instruction signal is input by the user using the input device  25   a.    
     (Step S 12 ) The analysis condition setting unit  31  judges whether a new analysis is to be conducted, based on the input instruction signal. The process moves to step S 13  if a new analysis is to be conducted, and moves to step S 14  if a reanalysis is to be conducted. 
     (Step S 13 ) When a new analysis is to be conducted, the analysis condition setting unit  31  sets analysis conditions in association with the design dataset of an object for a structural analysis. For example, the analysis condition setting unit  31  controls the image signal processing unit  24  to display a 3D image of the object on the screen of the display  24   a . Then, the analysis condition setting unit  31  receives, via the input signal processing unit  25 , analysis conditions individually specified by the user using the input device  25   a  for desired regions (each of which is not only a surface or solid but also a point or edge in the following description) within the object. Subsequently, the analysis condition setting unit  31  sets each of the analysis conditions in association with coordinate information of its corresponding region, included in the design dataset. 
       FIG. 5  illustrates a setting example of analysis conditions. 
     The object  15  of  FIG. 5  is the same as one illustrated in  FIG. 1 . The object  15  has a plurality of surfaces including surfaces  15   a ,  15   b ,  15   c ,  15   d ,  15   e ,  15   f ,  15   g ,  15   h ,  15   i ,  15   j ,  15   k ,  151 , and  15   m . For example, on a 3D image of the object  15  displayed on the screen, the user specifies, using the input device  25   a , each region for which an analysis condition is to be set and details of the analysis condition according to the type of a structural analysis to be conducted. 
     In the example of  FIG. 5 , an analysis condition that the solid object  15  is made of SS400 (a type of steel) is set. In addition, an analysis condition that a uniformly distributed load of 1000N is applied in the −x direction is set for the surface  15   a . Further, an analysis condition of complete constraint (i.e., being locked in all directions) is set for the surfaces  151  and  15   m.    
     The analysis condition setting unit  31  stores, in the analysis condition information storing unit  36 , information on the analysis conditions set in the above-described manner. 
     After step S 13 , the process moves to step S 18 . 
     (Step S 14 ) On the other hand, when a reanalysis is to be conducted, the corresponding relationship identifying unit  32  judges whether a design dataset corresponding to a pre-change object (a pre-update design dataset) has already been read, for example, from the HDD  23 . The process moves to step S 15  if it has yet to be read, and moves to step S 16  if it has already been read. 
     (Step S 15 ) The corresponding relationship identifying unit  32  reads the pre-update design dataset, for example, from the HDD  23 . At this time, the corresponding relationship identifying unit  32  may cause the display  24   a  to present a screen for selection of a pre-update design dataset and then read a selected design dataset from the HDD  23 . 
     (Step S 16 ) The corresponding relationship identifying unit  32  identifies a corresponding relationship between regions each included in the pre-update and post-update design datasets, based on coordinate information included in the individual pre-update and post-update design datasets. 
     (Step S 17 ) Based on each of the identified corresponding relationships, the analysis condition setting unit  31  sets an analysis condition in association with the post-update design dataset. 
     An example of processing in steps S 16  and S 17  above is described later. 
     (Step S 18 ) The simulation executing unit  33  runs a structural analysis simulation of the object based on the design dataset and the analysis conditions set in association with the design dataset. 
     (Step S 19 ) The display unit  34  controls the image signal processing unit  24  to present results of the structural analysis simulation on the screen of the display  24   a.    
     Next described is an example of the process of identifying a corresponding relationship between regions each included in the pre-update and post-update design datasets and the process of setting each analysis condition in association with the post-update design dataset. 
       FIG. 6  is a flowchart illustrating an example of a process of identifying a corresponding relationship between regions each included in the pre-update and post-update design datasets and a process of setting each analysis condition in association with the post-update design dataset. 
     (Step S 20 ) The corresponding relationship identifying unit  32  selects one analysis condition set for regions included in the pre-update design dataset. For example, as depicted in  FIG. 5 , conditions each regarding the material, load, or constraint are set for regions included in the design dataset of the object  15  as analysis conditions. The corresponding relationship identifying unit  32  selects one of the analysis conditions. 
     (Step S 21 ) Next, the corresponding relationship identifying unit  32  selects one region for which the selected analysis condition is set. Assuming that the analysis condition of “CONSTRAINT: COMPLETE CONSTRAINT” is selected in step S 20  amongst the analysis conditions depicted in  FIG. 5 , there are two regions for which the analysis condition is set, i.e., the surfaces  151  and  15   m . In this case, the corresponding relationship identifying unit  32  selects one of them. 
     (Step S 22 ) The corresponding relationship identifying unit  32  performs a process of determining, within the post-update design dataset, a region that matches the selected region. 
     Next described are examples of the determining process. Note that each region for which an analysis condition is set is not only a surface or solid but also a point or edge. 
     (Match Determination Process for Points) 
     In the case where a point for which an analysis condition is set is included in the pre-update design dataset, the corresponding relationship identifying unit determines, within the post-update design dataset, a point whose coordinate information matches that of the point included in the pre-update design dataset. 
     In some cases, a plurality of points having the same coordinate information is included in a single design dataset. This situation occurs, for example, when a point on a contact surface of two objects is defined for each of the objects. In that case, the corresponding relationship identifying unit  32  identifies a solid whose coordinate information matches that of a solid including the point with the analysis condition set, and determines a point included in the identified solid as a point that matches the point with the analysis condition set. If there is no solid including the point with the analysis condition set, the corresponding relationship identifying unit  32  identifies, within the post-update design dataset, a surface (or edge) whose coordinate information matches that of a surface (or edge if there is no surface) including the point with the analysis condition set, and determines a point included in the identified surface (or edge) as a point that matches the point with the analysis condition set. If, in this procedure, no matching solid, surface, or edge is found, no matching point is determined (“undetermined”). Note that match determination processes for solids, surfaces, and edges are described below. 
     In the case where the pre-update and post-update design datasets individually represent models each consisting of a single point, the corresponding relationship identifying unit  32  determines the point of the post-update design dataset as a point that matches the point with the analysis condition set, instead of performing the above-described match determination procedure using coordinate information. 
     (Match Determination Process for Edges) 
     In the case where an edge for which an analysis condition is set is included in the pre-update design dataset, the corresponding relationship identifying unit  32  determines, within the post-update design dataset, an edge having end and middle points whose coordinate information matches that of end and middle points (the number of middle points is optional) of the edge with the analysis condition set. 
     As for determining, within the post-update design dataset, an edge that matches the edge with the analysis condition set, a match on the type of an edge (straight line, arc, spline, or the like) and a match on the length of the edge may be added as determining conditions. The type of an edge is determined by information on the edge, included in a corresponding design dataset. This is because the information on an edge being an arc of a circle includes an entry on the radius, and the information on an edge being a spline includes an entry on control points. 
     As is the case in points, a plurality of edges having the same coordinate information is included in a single design dataset in some cases. This situation occurs, for example, when an edge on a contact surface of two objects is defined for each of these objects. In that case, the corresponding relationship identifying unit  32  identifies a solid whose coordinate information matches that of a solid including the edge with the analysis condition set, and determines an edge included in the identified solid as an edge that matches the edge with the analysis condition set. 
       FIG. 7  illustrates an example in which a plurality of edges that matches an edge with an analysis condition set is included in a post-update design dataset. 
     Assume in an object  40  that, for example, an analysis condition is set for an edge  40   a  on the contact surface between the objects  40  and  15 . In such a case, in objects  16  and  41  modified by a design change, two edges, that is, an edge  16   b  included in the object  16  and an edge  41   a  included in the object  41 , may be detected as edges that match the edge  40   a  of the object  40 .  FIG. 7  depicts, for convenience, the edges  16   b  and  41   a  separated from each other; however, in reality, these edges  16   b  and  41   a  exactly coincide with each other. 
     Hence, the corresponding relationship identifying unit  32  searches the post-update design dataset for a solid whose coordinate information matches that of a solid including the edge  40   a , i.e., the object  40 . If the object  41  is determined as a solid whose coordinate information matches that of the object  40 , the corresponding relationship identifying unit  32  determines the edge  41   a  belonging to the object  41  as an edge that matches the edge  40   a.    
     Note that, if there is no solid including the edge with the analysis condition set, the corresponding relationship identifying unit  32  identifies, within the post-update design dataset, a surface whose coordinate information matches that of a surface including the edge with the analysis condition set, and determines an edge included in the identified surface as an edge that matches the edge with the analysis condition set. If, in this procedure, no matching solid or surface is found, no matching edge is determined (“undetermined”). Note that match determination processes for solids and surfaces are described below. 
     In the case where the pre-update and post-update design datasets individually represent models each consisting of a single edge, the corresponding relationship identifying unit  32  determines the edge of the post-update design dataset as an edge that matches the edge with the analysis condition set, instead of performing the above-described match determination procedure using coordinate information. 
     (Match Determination Process for Surfaces) 
     In the case where a surface for which an analysis condition is set is included in the pre-update design dataset, the corresponding relationship identifying unit  32  determines, within the post-update design dataset, a surface having edges whose coordinate information matches that of all edges on the surface with the analysis condition set and representative points whose coordinate information matches that of all representative points (the number of representative points is optional) on the surface with the analysis condition set. A procedure for match determination for edges here follows the above-described match determination process for edges, and a procedure for match determination for representative points here follows the above-described match determination process for points. 
     As for determining, within the post-update design dataset, a surface that matches the surface with the analysis condition set, a match on the type of a surface (flat, cylindrical, conical, or the like) and a match on the surface area may be added as determining conditions. The type of a surface is determined by information on the surface, included in a corresponding design dataset. 
     As is the case in points and edges, a plurality of surfaces having the same coordinate information is included in a single design dataset in some cases. This situation occurs, for example, when a contact surface of two objects is defined for each of these objects. In that case, the corresponding relationship identifying unit  32  identifies, within the post-update design dataset, a solid whose coordinate information matches that of a solid including the surface with the analysis condition set, and determines a surface included in the identified solid as a surface that matches the surface with the analysis condition set. If, in this procedure, no matching solid is found, no matching surface is determined (“undetermined”). Note that a matching determination process for solids is described below. 
     In the case where the pre-update and post-update design datasets individually represent models each consisting of a single surface, the corresponding relationship identifying unit  32  determines the surface of the post-update design dataset as a surface that matches the surface with the analysis condition set, instead of performing the above-described match determination procedure using coordinate information. 
     (Match Determination Process for Solids) 
     In the case where a solid for which an analysis condition is set is included in the pre-update design dataset, the corresponding relationship identifying unit determines, within the post-update design dataset, a solid having surfaces whose coordinate information matches that of all surfaces on the solid with the analysis condition set. A procedure for match determination for surfaces here follows the above-described match determination process for surfaces. 
     As for determining, within the post-update design dataset, a solid that matches the solid with the analysis condition set, a match on the type of a solid (a rectangular parallelepiped, cube, cylinder, or the like), a match on the solid volume, a match on the solid&#39;s center of gravity, and a match on points within each solid may be added as determining conditions. The type of a solid is determined by information on the solid included in a corresponding design dataset. 
     If a plurality of solids that match the solid with the analysis condition set is found in the post-update design dataset, no matching solid is determined (“undetermined”). 
     In the case where the pre-update and post-update design datasets individually represent models each consisting of a single solid, the corresponding relationship identifying unit  32  determines the solid of the post-update design dataset as a solid that matches the solid with the analysis condition set, instead of performing the above-described match determination procedure using coordinate information. 
     (Step S 23 ) The corresponding relationship identifying unit  32  judges whether, within the post-update design dataset, a region that matches the region with the analysis condition set has been determined by the above-described process. The process moves to step S 24  if, within the post-update design dataset, a region that matches the region with the analysis condition set has been determined, and moves to step S 25  if not. 
     (Step S 24 ) The analysis condition setting unit sets the analysis condition for the matching region included in the post-update design data, determined by the corresponding relationship identifying unit  32 . 
     (Step S 25 ) When having failed to determine, within the post-update design dataset, a region that matches the region with the analysis condition set, the corresponding relationship identifying unit  32  tentatively determines, within the post-update design dataset, a region for which the analysis condition is to be set. Next described are examples of the tentative determination process. 
     Based on coordinate information, the corresponding relationship identifying unit  32  identifies, within the post-update design dataset, a region similar to the region with the analysis condition set, included in the pre-update design dataset, and tentatively determines the identified region as a region for which the analysis condition is to be set. Note that the similar region identified by the corresponding relationship identifying unit  32  is, for example, regions sharing common elements. The corresponding relationship identifying unit  32  performs, for example, the following process according to the shape of the region. 
     (Tentative Match Determination Process for Points) 
     When, in step S 22 , no point that matches the point with the analysis condition set is determined in the post-update design dataset, the corresponding relationship identifying unit  32  extracts, from the post-update design dataset, a point represented by coordinate information closest to that of the point with the analysis condition set. Then, the corresponding relationship identifying unit  32  tentatively determines the extracted point as a point for which the analysis condition is to be set. The corresponding relationship identifying unit  32  may calculate a value indicating the degree of match according to the distance between the point with the analysis condition set and the tentatively determined point. The corresponding relationship identifying unit  32  may designate, as tentatively determined targets, a plurality of points each associated with a value indicating a different degree of match. 
     (Tentative Match Determination Process for Edges) 
     When, in step S 22 , no edge that matches the edge with the analysis condition set is determined in the post-update design dataset, the corresponding relationship identifying unit  32  tentatively determines an edge for which the analysis condition is to be set, for example, using one of the following three methods. 
     (Method 1) The corresponding relationship identifying unit  32  designates, as a tentatively determined target, an edge having the highest number of points whose coordinate information individually matches that of each point (end or middle point) of the edge with the analysis condition set. At this time, the corresponding relationship identifying unit  32  may use a tentatively determined point corresponding to each point of the edge with the analysis condition set. This scheme is adopted in order to prevent a lot of edges from failing to be tentatively determined. The scheme may also be adopted by Method 2 described below. 
     (Method 2) Assume that the post-update design dataset includes a plurality of edges having points whose coordinate information matches that of each point of the edge with the analysis condition set. Assume also that the plurality of edges includes not only these points whose coordinate information matches that of each point of the edge with the analysis condition set, but also other points with matching coordinate information. Further assume that the total length of a group formed of the plurality of edges (i.e., the sum of the length of the edges) coincides with the length of the edge with the analysis condition set. In this case, the corresponding relationship identifying unit  32  tentatively determines this group as an edge that matches the edge with the analysis condition set. 
     There may be no group consisting of a plurality of edges, whose total length exactly coincides with the length of the edge with the analysis condition set. In that case, the corresponding relationship identifying unit  32  may select, as a tentatively determined target, a group with total length which most closely matches the length of the edge with the analysis condition set. 
       FIG. 8  illustrates an example of Method 2 for tentatively determining a matching edge or edges. 
     Assume that, in  FIG. 8 , an edge  50  with end points  51   a  and  51   b  is defined in a pre-update design dataset. However, a design change of a corresponding object causes a change in the definition of the edge  50 , and two edges  52   a  and  52   b  are defined in a post-update design dataset, in place of the edge  50 . If an analysis condition has been set for the edge  50 , the corresponding relationship identifying unit  32  performs a procedure described next. 
     If having detected the edge  52   a  having an end point  53   a  whose coordinate information matches that of the end point  51   a  and the edge  52   b  having an end point  53   c  whose coordinate information matches that of the end point  51   b , the corresponding relationship identifying unit  32  judges whether the other end points of the individual edges  52   a  and  52   b  have the same coordinate information. In the example of  FIG. 8 , an end point  53   b  is shared by the edges  52   a  and  52   b , and it thus turns out that the other end points of the two edges  52   a  and  52   b  match each other. In this case, the corresponding relationship identifying unit  32  calculates the sum of the length of the edges  52   a  and  52   b . If the calculated sum of the length matches the length of the edge  50 , then the corresponding relationship identifying unit  32  tentatively determines a group consisting of the edges  52   a  and  52   b  as an edge for which the analysis condition is to be set. 
     Thus, this procedure provides an opportunity of setting an analysis condition (to be described later) to the group described above even if a design change of a corresponding object has caused a change in the definition of an edge. 
     If, by Method 2 above, the total length of the group is different from the length of the edge with the analysis condition set, the corresponding relationship identifying unit  32  designates the edge obtained by Method 1 as a tentatively determined target. On the other hand, if, by Method 2, the total length of the group coincides with the length of the edge with the analysis condition set, the corresponding relationship identifying unit  32  does not use the edge obtained by Method 1 and designates the group obtained by Method 2 as a tentatively determined target instead. 
     If a design change of a corresponding object causes a change in the definition associated with edges in such a manner that a plurality of edges, for each of which an analysis condition is set, is changed to a single edge (that is, the change here is caused in an inverse manner to the change described above), the corresponding relationship identifying unit  32  may designate, with respect to each of the plurality of edges, the common single edge as a tentatively determined target. 
     Assume that, for example, the post-update design dataset includes a single edge having points whose coordinate information matches that of individual points included in each of a plurality of edges for which the same analysis condition is set. Assume also that the plurality of edges includes not only these points whose coordinate information matches that of each point of the edge included in the post-update design dataset, but also other points with matching coordinate information. Further, assume that the total length of a group formed of the plurality of edges (i.e., the sum of the length of the edges) each with the analysis condition set coincides with the length of the single edge included in the post-update design dataset. In this case, the corresponding relationship identifying unit  32  tentatively determines the single edge in the post-update design dataset as an edge that matches the plurality of edges with the analysis condition set. This procedure is carried out, for example, when the edges  52   a  and  52   b  of  FIG. 8  are edges with the analysis condition set and the edge  50  is an edge included in the post-update design dataset. 
     (Method 3) If no edge having points whose coordinate information individually matches that of each point (end or middle point) of the edge with the analysis condition set is found in the post-update design dataset, the corresponding relationship identifying unit  32  executes, for example, the following procedure based on the type of the edge with the analysis condition set. 
     When the edge with the analysis condition set is a straight line, the corresponding relationship identifying unit  32  selects, amongst edges included in the post-update design dataset, an edge parallel and closest in distance to the edge with the analysis condition set as a tentatively determined target. 
     When the edge with the analysis condition set is not a straight line, the corresponding relationship identifying unit  32  selects a tentatively determined target, for example, in the following manner. The corresponding relationship identifying unit  32  identifies, amongst edges included in the post-update design dataset, edges whose type and length coincide with the edge with the analysis condition set and which are located parallel to the edge with the analysis condition set. Then, the corresponding relationship identifying unit  32  designates, amongst the identified edges, an edge closest in distance to the edge with the analysis condition set as the tentatively determined target. Alternatively, the corresponding relationship identifying unit  32  identifies, amongst the edges included in the post-update design dataset, edges whose type coincides with the edge with the analysis condition set and which lie in the same plane as the edge with the analysis condition set, and designates, amongst the identified edges, an edge closest in distance to the edge with the analysis condition set as the tentatively determined target. 
     The corresponding relationship identifying unit  32  may calculate a value indicating the degree of match between the edge with the analysis condition set and the tentatively determined edge. For example, if the tentatively determined edge has a higher number of points whose coordinate information individually matches that of each point (end or middle point) of the edge with the analysis condition set, the corresponding relationship identifying unit  32  assigns a value indicating a higher degree of match. Alternatively, the corresponding relationship identifying unit  32  may calculate the value indicating the degree of match, for example, based on the ratio between the length of the edge with the analysis condition set and that of the tentatively determined edge (the total length in the case where the tentatively determined edge is formed of a group of edges) or the degree of proximity between the edge with the analysis condition set and the tentatively determined edge. The degree of match is numerically represented, for example, by a value between 0 and 1, with a value closer to 1 indicating a higher degree of match. Further, alternatively, the corresponding relationship identifying unit  32  may calculate a value indicating the degree of match for each of such conditions as mentioned above and multiply the calculated values, and then output the multiplication result as the final index for the degree of match. 
     Note that the corresponding relationship identifying unit  32  may designate, as tentatively determined targets, a plurality of edges each associated with a value indicating a different degree of match. 
     (Tentative Match Determination Process for Surfaces) 
     When, in step S 22 , no surface that matches the surface with the analysis condition set is determined in the post-update design dataset, the corresponding relationship identifying unit  32  tentatively determines a surface for which the analysis condition is to be set, for example, using one of the following three methods. 
     (Method 1) The corresponding relationship identifying unit  32  designates, as a tentatively determined target, a surface having the highest number of edges whose coordinate information individually matches that of each edge of the surface with the analysis condition set. At this time, the corresponding relationship identifying unit  32  may use a tentatively determined edge corresponding to each edge of the surface with the analysis condition set. This scheme is adopted in order to prevent a lot of surfaces from failing to be tentatively determined. The scheme may also be adopted by Method 2 described below. 
     (Method 2) Assume that the post-update design dataset includes a plurality of surfaces each having one or more edges whose coordinate information matches that of one or more of a plurality of edges of the surface with the analysis condition set, and that the plurality of surfaces also includes other edges that share the same coordinate information. Further, assume that the total area of a group formed of the plurality of surfaces coincides with the area of the surface with the analysis condition set. In this case, the corresponding relationship identifying unit  32  tentatively determines this group as a surface that matches the surface with the analysis condition set. 
     There may be no group consisting of a plurality of surfaces, whose total area exactly coincides with the area of the surface with the analysis condition set. In that case, the corresponding relationship identifying unit  32  may select, as a tentatively determined target, a group with total area which most closely matches the area of the surface with the analysis condition set. 
       FIG. 9  illustrates an example of Method 2 for tentatively determining a matching surface or surfaces. 
     Assume that, in  FIG. 9 , a surface  60  with edges  61   a  and  61   b  is defined in a pre-update design dataset. However, a design change of a corresponding object causes a change in the definition of the surface  60 , and two surfaces  62   a  and  62   b  are defined in a post-update design dataset, in place of the surface  60 . If an analysis condition has been set for the surface  60 , the corresponding relationship identifying unit  32  performs a procedure described next. 
     If having detected the surface  62   a  having an edge  63   a  whose coordinate information matches that of the edge  61   a  and the surface  62   b  having an edge  63   b  whose coordinate information matches that of the edge  61   b , the corresponding relationship identifying unit  32  judges whether different edges of the individual surfaces  62   a  and  62   b  share the same coordinate information. In the example of  FIG. 9 , an edge  63   c  is shared by the surfaces  62   a  and  62   b , and it thus turns out that the different edges of the two surfaces  62   a  and  62   b  match each other. In this case, the corresponding relationship identifying unit  32  calculates the sum of the area of the surfaces  62   a  and  62   b . If the calculated sum of the area matches the area of the surface  60 , then the corresponding relationship identifying unit  32  tentatively determines a group consisting of the surfaces  62   a  and  62   b  as a surface for which the analysis condition is to be set. 
     Thus, this procedure provides an opportunity of setting an analysis condition (to be described later) to the group described above even if a design change of a corresponding object has caused a change in the definition of a surface. 
     If, by Method 2 above, the total area of the group is different from the area of the surface with the analysis condition set, the corresponding relationship identifying unit  32  designates the surface obtained by Method 1 as a tentatively determined target. On the other hand, if, by Method 2, the total area of the group coincides with the area of the surface with the analysis condition set, the corresponding relationship identifying unit  32  does not use the surface obtained by Method 1 and designates the group obtained by Method 2 as a tentatively determined target instead. 
     If a design change of a corresponding object causes a change in the definition associated with surfaces in such a manner that a plurality of surfaces, for each of which an analysis condition is set, is changed to a single surface (that is, the change here is caused in an inverse manner to the change described above), the corresponding relationship identifying unit  32  may designate, with respect to each of the plurality of surfaces, the common single surface as a tentatively determined target. 
     Assume that, for example, the post-update design dataset includes a single surface having edges whose coordinate information individually matches that of an edge included in each of a plurality of surfaces for which the same analysis condition is set. Assume also that the plurality of surfaces includes not only these edges whose coordinate information individually matches that of each edge of the surface included in the post-update design dataset, but also other edges with matching coordinate information. Further, assume that the total area of a group formed of the plurality of surfaces (i.e., the sum of the area of the individual surfaces) each with the analysis condition set coincides with the area of the single surface included in the post-update design dataset. In this case, the corresponding relationship identifying unit  32  tentatively determines the single surface in the post-update design dataset as a surface that matches the plurality of surfaces with the analysis condition set. This procedure is carried out, for example, when the surfaces  62   a  and  62   b  of  FIG. 9  are surfaces with the analysis condition set and the surface  60  is a surface included in the post-update design dataset. 
     (Method 3) If no surface having edges whose coordinate information individually matches that of each edge of the surface with the analysis condition set is found in the post-update design dataset, the corresponding relationship identifying unit  32  executes, for example, the following procedure based on the type of the surface with the analysis condition set. 
     When the surface with the analysis condition set is a planar surface, the corresponding relationship identifying unit  32  selects, amongst surfaces included in the post-update design dataset, a surface parallel and closest in distance to the surface with the analysis condition set as a tentatively determined target. 
     When the surface with the analysis condition set is not a planar surface (i.e., curved surface), the corresponding relationship identifying unit  32  selects a tentatively determined target, for example, in the following manner. The corresponding relationship identifying unit  32  identifies, amongst curved surfaces included in the post-update design dataset, curved surfaces whose type and area coincide with the curved surface with the analysis condition set and which are located parallel to the curved surface with the analysis condition set. Then, the corresponding relationship identifying unit  32  designates, amongst the identified curved surfaces, a curved surface closest in distance to the curved surface with the analysis condition set as the tentatively determined target. Alternatively, the corresponding relationship identifying unit  32  identifies, amongst the curved surfaces included in the post-update design dataset, curved surfaces whose type coincides with the curved surface with the analysis condition set and which are located parallel to the curved surface with the analysis condition set. Then, the corresponding relationship identifying unit  32  designates, amongst the identified curved surfaces, a curved surface closest in distance to the curved surface with the analysis condition set as the tentatively determined target. Further, alternatively, the corresponding relationship identifying unit  32  identifies, amongst the curved surfaces included in the post-update design dataset, curved surfaces whose type coincides with the curved surface with the analysis condition set and which lie in the same curved plane as the curved surface with the analysis condition set. Then, the corresponding relationship identifying unit  32  designates, amongst the identified curved surfaces, a curved surface closest in distance to the curved surface with the analysis condition set as the tentatively determined target. The curved surface closest in distance amongst the curved surfaces lying in the same curved plane as the curved surface with the analysis condition set is, for example, a curved surface having a largest overlap in area with the curved surface with the analysis condition set, or a curved surface having its center of gravity closest to the curved surface with the analysis condition set. 
     The corresponding relationship identifying unit  32  may calculate a value indicating the degree of match between the surface with the analysis condition set and the tentatively determined surface. For example, if the tentatively determined surface has a higher number of edges whose coordinate information individually matches that of each edge of the surface with the analysis condition set, the corresponding relationship identifying unit  32  assigns a value indicating a higher degree of match. Alternatively, the corresponding relationship identifying unit  32  may calculate the value indicating the degree of match, for example, based on the ratio between the area of the surface with the analysis condition set and that of the tentatively determined surface (the sum of the area in the case where the tentatively determined surface is formed of a group of surfaces) or the degree of proximity between the surface with the analysis condition set and the tentatively determined surface. Further, alternatively, the corresponding relationship identifying unit  32  may calculate a value indicating the degree of match for each of such conditions as mentioned above and multiply the calculated values, and then output the multiplication result as the final index for the degree of match. 
     Note that the corresponding relationship identifying unit  32  may designate, as tentatively determined targets, a plurality of surfaces each associated with a value indicating a different degree of match. 
     (Tentative Match Determination Process for Solids) 
     When, in step S 22 , no solid that matches the solid with the analysis condition set is determined in the post-update design dataset, the corresponding relationship identifying unit  32  tentatively determines a solid for which the analysis condition is to be set, for example, using one of the following three methods. 
     (Method 1) The corresponding relationship identifying unit  32  designates, as a tentatively determined target, a solid having the highest number of surfaces whose coordinate information individually matches that of each surface of the solid with the analysis condition set. At this time, the corresponding relationship identifying unit  32  may use a tentatively determined surface corresponding to each surface of the solid with the analysis condition set. This scheme is adopted in order to prevent a lot of solids from failing to be tentatively determined. The scheme may also be adopted by Method 2 described below. 
     (Method 2) Assume that the post-update design dataset includes a plurality of solids each having one or more surfaces whose coordinate information matches that of one or more of a plurality of surfaces of the solid with the analysis condition set, and that the plurality of solids also includes other surfaces that share the same coordinate information. Further, assume that the total volume of a group formed of the plurality of solids coincides with the volume of the solid with the analysis condition set. In this case, the corresponding relationship identifying unit  32  tentatively determines this group as a solid that matches the solid with the analysis condition set. 
     There may be no group consisting of a plurality of solids, whose total volume exactly coincides with the volume of the solid with the analysis condition set. In that case, the corresponding relationship identifying unit  32  may select, as a tentatively determined target, a group with total volume which most closely matches the volume of the solid with the analysis condition set. 
       FIG. 10  illustrates an example of Method 2 for tentatively determining a matching solid or solids. 
     Assume that, in  FIG. 10 , a solid  70  with surfaces  71   a  and  71   b  is defined in a pre-update design dataset. However, a design change of a corresponding object causes a change in the definition of the solid  70 , and two solids  72   a  and  72   b  are defined in a post-update design dataset, in place of the solid  70 . If an analysis condition has been set for the solid  70 , the corresponding relationship identifying unit  32  performs a procedure described next. 
     If having detected the solid  72   a  having a surface  73   a  whose coordinate information matches that of the surface  71   a  and the solid  72   b  having a surface  73   b  whose coordinate information matches that of the surface  71   b , the corresponding relationship identifying unit  32  judges whether different surfaces on the individual solids  72   a  and  72   b  share the same coordinate information. In the example of  FIG. 10 , a surface  73   c  is shared by the solids  72   a  and  72   b , and it thus turns out that the different surfaces of the two solids  72   a  and  72   b  match each other. In this case, the corresponding relationship identifying unit  32  calculates the sum of the volume of the solids  72   a  and  72   b . If the calculated sum of the volume matches the volume of the solid  70 , then the corresponding relationship identifying unit  32  tentatively determines a group consisting of the solids  72   a  and  72   b  as a solid for which the analysis condition is to be set. 
     Thus, this procedure provides an opportunity of setting an analysis condition (to be described later) to the group described above even if a design change of a corresponding object has caused a change in the definition of a solid. 
     If, by Method 2 above, the total volume of the group is different from the volume of the solid with the analysis condition set, the corresponding relationship identifying unit  32  designates the solid obtained by Method 1 as a tentatively determined target. On the other hand, if, by Method 2, the total volume of the group coincides with the volume of the solid with the analysis condition set, the corresponding relationship identifying unit  32  does not use the solid obtained by Method 1 and designates the group obtained by Method 2 as a tentatively determined target instead. 
     If a design change of a corresponding object causes a change in the definition associated with solids in such a manner that a plurality of solids, for each of which an analysis condition is set, is changed to a single solid (that is, the change here is caused in an inverse manner to the change described above), the corresponding relationship identifying unit  32  may designate, with respect to each of the plurality of solids, the common single solid as a tentatively determined target. 
     Assume that, for example, the post-update design dataset includes a single solid having surfaces whose coordinate information individually matches that of a surface included in each of a plurality of solids for which the same analysis condition is set. Assume also that the plurality of solids includes not only these surfaces whose coordinate information individually matches that of each surface on the solid included in the post-update design dataset, but also other surfaces with matching coordinate information. Further, assume that the total volume of a group formed of the plurality of solids (i.e., the sum of the volume of the individual solids) each with the analysis condition set coincides with the volume of the single solid included in the post-update design dataset. In this case, the corresponding relationship identifying unit  32  tentatively determines the single solid in the post-update design dataset as a solid that matches the plurality of solids with the analysis condition set. This procedure is carried out, for example, when the solids  72   a  and  72   b  of  FIG. 10  are solids with the analysis condition set and the solid  70  is a solid included in the post-update design dataset. 
     (Method 3) If no solid having surfaces whose coordinate information individually matches that of each surface of the solid with the analysis condition set is found in the post-update design dataset, the corresponding relationship identifying unit  32  executes, for example, the following procedure. 
     The corresponding relationship identifying unit  32  designates, amongst solids included in the post-update design dataset, a solid whose center of gravity comes closest to the solid with the analysis condition set as a tentatively determined target. Alternatively, the corresponding relationship identifying unit  32  designates, amongst the solids included in the post-update design dataset, a solid having a volume closest to that of the solid with the analysis condition set. Further, alternatively, assuming that surfaces individually lying in the same curved plane as each curved surface defining the solid with the analysis condition set are recognized as matching surfaces, the corresponding relationship identifying unit  32  designates, amongst the solids included in the post-update design dataset, a solid having a highest number of matching surfaces as a tentatively determined target. 
     The corresponding relationship identifying unit  32  may calculate a value indicating the degree of match between the solid with the analysis condition set and the tentatively determined solid. For example, if the tentatively determined solid has a higher number of surfaces whose coordinate information individually matches that of each surface of the solid with the analysis condition set, the corresponding relationship identifying unit  32  assigns a value indicating a higher degree of match. Alternatively, the corresponding relationship identifying unit  32  may calculate the value indicating the degree of match, for example, based on the ratio between the volume of the solid with the analysis condition set and that of the tentatively determined solid (the sum of the volume in the case where the tentatively determined solid is formed of a group of solids) or how close the center of gravity of the tentatively determined solid (the degree of proximity) to the solid with the analysis condition set. Further, alternatively, the corresponding relationship identifying unit  32  may calculate a value indicating the degree of match for each of such conditions as mentioned above and multiply the calculated values, and then output the multiplication result as the final index for the degree of match. 
     Note that the corresponding relationship identifying unit  32  may designate, as tentatively determined targets, a plurality of solids each associated with a value indicating a different degree of match. 
     The corresponding relationship identifying unit stores, in the tentatively determined region storing unit  37 , information on one or more regions (points, edges, surfaces, or solids) tentatively determined in the above-described manner, the analysis condition to be set for the regions, and values each indicating the degree of match if the values have been calculated. 
     (Step S 26 ) After steps S 24  and S 25 , the analysis condition setting unit  31  judges whether, in step S 21 , all regions for which the analysis condition selected in step S 20  is set have been selected from the pre-update design dataset. The process returns to step S 21  if any pending region with the analysis condition set remains, and moves to step S 27  if all the regions with the analysis condition set have already been selected. 
     (Step S 27 ) The analysis condition setting unit judges whether, in step S 20 , all analysis conditions have been selected from the pre-update design dataset. The process returns to step S 20  if any pending analysis condition remains, and moves to step S 28  if all the analysis conditions have already been selected. 
     (Step S 28 ) The display unit  34  judges whether there are one or more tentatively determined regions. If there is no tentatively determined region, the corresponding relationship identification process and the analysis condition setting process end. If there are one or more tentatively determined regions, the process moves to step S 29 . 
     (Step S 29 ) Based on information about the tentatively determined regions, stored in the tentatively determined region storing unit  37 , the display unit  34  causes the display  24   a  to present a screen for prompting the user to decide whether to set a corresponding analysis condition for each tentatively determined region. If the information about the tentatively determined regions in the tentatively determined region storing unit  37  includes values each indicating the degree of match, the display unit  34  causes the display  24   a  to also present these values. In addition, the display unit  34  may cause the display  24   a  to also present regions for which matching regions have been determined and those for which no matching regions have been determined (undetermined regions). 
     (Step S 30 ) The analysis condition setting unit  31  judges whether the user has instructed, using the input device  25   a , to set a corresponding analysis condition for each tentatively determined region. If no instruction for setting analysis conditions for the tentatively determined regions is received from the user, the corresponding relationship identification process and the analysis condition setting process end. On the other hand, the process moves to step S 31  if an instruction for setting analysis conditions for the tentatively determined regions is received. 
     Note that the analysis condition setting unit  31  may also receive, from the user, an instruction to set or change an analysis condition for each undetermined or determined region. 
     (Step S 31 ) Based on the content of the instruction from the user, the analysis condition setting unit  31  sets a corresponding analysis condition for each tentatively determined region. In addition, if having received, from the user, an instruction to set or change an analysis condition for each undetermined or determined region, the analysis condition setting unit  31  sets or changes the analysis condition based on the content of the received instruction. The analysis condition setting unit  31  stores, in the analysis condition information storing unit  36 , information about the analysis condition set or changed in this manner. 
     After these corresponding relationship identification process and the analysis condition setting process end, the process carried out by the information processor  20  moves to step S 18  described above. 
     Note that the sequence of the processing steps described above is merely an example and the embodiments herein are not limited in this respect. 
     As described above, the information processor  20  of the second embodiment sets each analysis condition in association with the post-update design dataset based on a corresponding relationship between regions each included in pre-update and post-update design datasets, identified from coordinate information included in the individual pre-update and post-update design datasets. This prevents unintentional analysis conditions from being set in association with the post-update design dataset, which could occur, for example, in associating each analysis condition with a shape ID, thus being able to avoid a structural analysis from yielding erroneous results. In addition, this technique reduces the need of resetting analysis conditions for the post-update design dataset in a reanalysis after a design change. 
     The information processor  20  also eliminates the need of holding shape IDs, which in turn eliminates the need of allocating memory space for the shape IDs. 
     In addition, even if the post-update design dataset does not include a region whose coordinate information matches that of a region for which an analysis condition is set, the information processor  20  identifies a region similar to the region with the analysis condition set and thus allows setting of the analysis condition to the identified similar region. At this time, the information processor  20  calculates a value indicating the degree of match between the region with the analysis condition set and the similar region and causes the display  24   a  to present the value, to thereby facilitate decision making by the user on whether to set the analysis condition for the similar region. 
     Note that the above-described processing details are implemented by causing the information processor  20  to execute a program, as described above. 
     Such a program may be recorded in a computer-readable storage medium (for example, the storage medium  26   a ). Examples of such a computer-readable storage medium include a magnetic disk, an optical disk, a magneto-optical disk, and semiconductor memory. Examples of the magnetic disk are a FD and a HDD. Examples of the optical disk are a compact disc (CD), CD-recordable (CD-R), CD-rewritable (CD-RW), DVD, DVD-R, and DVD-RW. The program may be recorded on portable storage media and then distributed. In such a case, the program may be executed after being copied from such a portable storage medium to a different storage medium (for example, the HDD  23 ). 
     According to one aspect, it is possible to prevent a structural analysis from yielding erroneous results. 
     All examples and conditional language provided herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.