JP2003288377A - Method for acquiring shortest distance between objects - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the processing time for acquiring the shortest distance between objects formed of a plurality of elements. <P>SOLUTION: This method includes the step for setting the shortest distance Dmin to an initial value; the step for determining an element of object based on a prescribed reading order differed from alignment order from a plurality elements constituting the object, and reading the position information of the element of object; the step for roughly determining the distance between the element of object and a prescribed point based on the position information of the element of object and setting it as a roughly determined distance Drgh; the step for comparing the roughly determined Drgh with the shortest distance Dmin and, when the roughly determined Drgh is the shortest distance Dmin or less, precisely determining the distance between the element of object and a prescribed point based on the position information of the element of object, and setting it as an element distance Dobj; and the step for substituting the element distance Dobj for the shortest distance Dmin when the element distance Dobj is the shortest distance Dmin or less. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to computer technology calculations such as CAD / CAM and CG, and in particular, between objects for obtaining the shortest distance between an object composed of a plurality of elements and a predetermined point. The shortest distance acquisition method.

[0002]

2. Description of the Related Art CAD / CAM and computer graphics are composed of a plurality of independent objects, and it is necessary to determine and represent interactions such as collision and contact of each object. In particular, when designing a product design by CAD / CAM, it is necessary to calculate the shortest distance between objects in order to recognize the state of interference between parts or manufacturing tools.

When the face of each object is expressed by a predetermined mathematical expression, the mathematical expression can be analyzed to calculate the shortest distance between the objects. In addition, each object is a polyhedron (polyhedro
n), the polyhedron can be decomposed into simple shape elements, and the shortest distance can be obtained based on the position information of each element.

[0004]

When the shortest distance is obtained by analyzing the mathematical expression expressing the face of each object, it is necessary to use the convergence operation and the like, which requires a lot of time for the operation. It contains a problem. When each object is decomposed into simple shape elements, the shortest distance of the polygons forming each object is sequentially obtained based on the position information of the triangular polygons forming the polyhedron.

A triangular polygon is an edge that indicates the boundary between elements, and a vertex that constitutes an end pair of edges.
x), a face representing the face of the element. This triangular polygon is divided in a geometrically continuous state, and its element data are generally arranged in an order based on the continuity. Usually, such polygon data is read in the order of alignment and the shortest distance is calculated, so that the processing takes a lot of time.

An object of the present invention is to shorten the processing time for acquiring the shortest distance between objects composed of a plurality of elements.

[0007]

A method for obtaining the shortest distance between objects according to the present invention is a method for obtaining the shortest distance between objects for obtaining the shortest distance between an object composed of a plurality of elements and a predetermined point. Therefore, the target element is determined based on A) a step of setting the shortest distance Dmin to an initial value, and B) a plurality of elements forming the object based on a predetermined reading order different from the arrangement order, and position information of the target element. And C) a step of simply determining the distance between the target element and a predetermined point based on the position information of the target element and setting the distance to the simple determination distance Drgh, and D) a simple determination distance Drgh.
And the shortest distance Dmin are compared with each other. If the simple determination distance Drgh exceeds the shortest distance Dmin, the process shifts to the B stage, and if the simple determination distance Drgh is the shortest distance Dmin or less, the position information of the target element is calculated. And E) comparing the element distance Dobj with the shortest distance Dmin, and making a detailed determination of the distance between the target element and the predetermined point based on
When j exceeds the shortest distance Dmin, the process shifts to the B step, and when the element distance Dobj is less than or equal to the shortest distance Dmin, the element distance Dobj is substituted for the shortest distance Dmin.
F) If there is one of the plurality of elements forming the object that is not the target element, the step moves to step B, and if it is determined that all the elements have become the target elements, the step of ending the process including.

Here, in the B stage, the target elements can be set every predetermined number a in the predetermined arrangement order (1 to N) of the number N of elements. In the B stage, 1, N, (1 + N) / 2, (1 + N) / 4, for the predetermined array order (1 to N) with the number of elements N,
The target element can be determined in the order of 3 (1 + N) / 4. Further, the object can have a plurality of polygon planes arranged in a three-dimensional space as elements.

The method for acquiring the shortest distance between objects according to the present invention is a method for acquiring the shortest distance between objects for acquiring the shortest distance between a first object and a second object that are composed of a plurality of elements. A)
The step of setting the shortest distance Dmin to an initial value, and B) determining the first target element based on a predetermined reading order different from the array order among the plurality of elements forming the first object, and determining the position of the first target element. The step of reading information, and C) determining the second target element based on a predetermined reading order different from the arrangement order from among the plurality of elements forming the second object, and
And a step of reading the position information of the target element, and D) simply determining the distance between the first target element and the second target element based on the position information of the first target element and the second target element to obtain the simple determination distance Drgh. The setting step and E) the simple determination distance Drgh and the shortest distance Dmin are compared, and when the simple determination distance Drgh exceeds the shortest distance Dmin, the process shifts to step C, and the simple determination distance Drgh is the shortest distance Dmin or less. If it is, the step of making a detailed determination of the distance between the first target element and the second target element based on the position information of the first target element and the second target element and setting it as the element distance Dobj, and F) the element distance Dobj Is compared with the shortest distance Dmin, and when the element distance Dobj exceeds the shortest distance Dmin, the process shifts to the C stage, and the element distance Dobj is the shortest distance Dm.
If it is less than or equal to in, the element distance Dobj is set to the shortest distance Dmin.
G), and if there is one of the plurality of elements constituting the second object that is not the second target element, the process proceeds to step C and all the elements become the second target element. If it is judged, the stage to shift to the H stage,
H) The first of the plurality of elements forming the first object
If there is any element that is not the target element, the process proceeds to step B, and if it is determined that all the elements have become the first target element, the process ends.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The shortest distance acquisition method between objects according to the present invention is installed as a part of an application of a computer that performs graphics processing such as CAD / CAM or CG. Will be described below. As shown in FIG. 1, the first object 10 and the second object 10
Consider a case where the shortest distance of the object 20 is acquired.

The illustrated first object 10 and second object
The object 20 is composed of a polyhedron in which polygon planes are continuous. The first object 10 includes a first element 101, a second element 102, and a triangle polygon.
The third element 103 ...
The first element 20 in which the object 20 is also a triangular polygon
It is assumed that it is composed of 1, a second element 202, a third element 203 ...

A first element 101 of the first object 10,
The position information of the second element 102, the third element 103, ...
The first elements 1 are arranged in a predetermined arrangement order in consideration of geometrical continuity, and are located, for example, at the bottom left of FIG.
The data array is configured so that adjacent elements are sequentially arranged from 01. Similarly, the first element 201, the second element 202, the third element 203, ... Of the second object 20.
Position information is also arranged in a predetermined array order in consideration of geometrical continuity, and for example, the data array is arranged so that adjacent elements are sequentially arranged from the first element 201 located at the upper right of FIG. Is configured.

In order to obtain the shortest distance between the first object 10 and the second object 20 as described above, for example, the distance from the first element 201 of the second object 20 to the first object 10 is calculated as follows. It is calculated in the order of arrangement of each element, and the shortest one is set as the provisional shortest distance between the objects. Further, from the second element 202, which is the next element of the second object 20, to the second element
The distance to the object 10 is calculated in the order in which the elements of the first object 10 are arranged, and if there is a value smaller than the provisional shortest distance, the data is updated sequentially.

In this way, the processing is executed up to the final element of the second object 20, and the obtained shortest distance is set as the shortest distance between the first object 10 and the second object 20. Here, in order to simplify the explanation, a case where the shortest distance between the predetermined point and the object is obtained will be considered. As shown in FIG. 2, the first object 10 has a first element 101, a second element 102, and a third element 103, as in FIG.
Consider the case where the shortest distance from the predetermined point 21 on the second object to the first object 10 is acquired.

A conventional example of the method for obtaining the shortest distance from the predetermined point 21 to the first object 10 is shown in the flowchart of FIG. In step S11, the shortest distance Dmin
Is set to a predetermined maximum value. Here, the maximum value corresponding to the number of digits of the variable used for calculation can be set as a default value, and can be set to 1.0E + 38, for example.

In step S12, the simple determination distance Drgh from the predetermined point 21 to the currently targeted i-th element 100 (i) is acquired. The i-th element 100 (i) of the first object 10 has three vertices V1 (x1, y2, z3), V2 (x2, y2, z2), V3 (x3, y3, z3) as shown in FIG. , The distance between the maximum area coordinate Vmax (xmax, ymax, zmax) and the minimum area coordinate Vmin (xmin, ymin, zmin) and the predetermined point 21 is calculated, and the smaller one is calculated by the simple determination distance D.
rgh.

In step S13, the simple determination distance Drgh
Is above the shortest distance Dmin. When it is determined that the simple determination distance Drgh exceeds the shortest distance Dmin, the process proceeds to step S12, and the simple determination distance Drgh
When it is determined that is less than or equal to the shortest distance Dmin, the process proceeds to step S14. In step S14, the predetermined point 21
And the i-th element 100 (i) are calculated in detail to obtain the element distance Dobj between the predetermined point 21 and the i-th element 100 (i). Here, the predetermined point 21 and the i-th element 100 (i)
The method of obtaining the distance between and is performed by using various proposed methods, and details thereof will not be mentioned here.

In step S15, it is determined whether the element distance Dobj is smaller than the shortest distance Dmin. Element distance Do
When bj is determined to be smaller than the shortest distance Dmin, the process proceeds to step S16, and when it is determined that the element distance Dobj is equal to or greater than the shortest distance Dobj, the process proceeds to step S12. In step S16, the value of the element distance Dobj is substituted for the shortest distance Dmin, and the data of the shortest distance Dmin is updated.

In step S17, the first object 1
It is determined whether or not the processing has been executed for all the elements of 0. If it is determined that some of the elements of the first object 10 have not been processed, the variable i is incremented and the same processing is executed for the next element. In this way, when the processing is executed in the order of arrangement of the elements of the first object 10, there may be a case where detailed distance calculation processing must be executed for all the elements.

For example, as shown in FIG. 5, when the distance to the first element 101 arranged at the head among the elements of the first object 10 is the shortest, detailed distance measurement is Only the first first element 101 need be processed. However, as shown in FIG. 6, in the case where the distance to the first element 101 arranged at the head among the respective elements of the first object 10 is the maximum and the distance of each element becomes shorter in the order of arrangement, Needs to make detailed distance measurements for all elements.

Further, as shown in FIG. 7, the fifth element 105
The number of detailed distance measurement processes differs between the case where the distance to the shortest distance is the shortest and the case where the distance to the tenth element 110 is the shortest, as shown in FIG. Table 1 shows the number of processes when the shortest distance is acquired for each model of FIGS. 5 to 8 by such conventional sequential distance acquisition.

[0022]

[Table 1] When the number of elements of the first object 10 is N, the average value of the number of processings of detailed distance measurement in such a sequential distance acquisition method can be represented by (N / 2) * K1. Here, K1 is a coefficient determined according to the type of shape of the first object 10 and the complexity of the shape.

FIG. 9 shows a flowchart of the method for acquiring the shortest distance between objects according to the present invention. Step S21
Then, the shortest distance Dmin is set to a predetermined maximum value. In the same way as above, the maximum value corresponding to the number of digits of the variable used for calculation can be set as the default value.
It can be +38.

In step S22, the first object 1
A processing order table NoTbl for determining the processing order is created for each element of 0. The processing order table NoTbl can be created, for example, by setting the processing order table NoTbl so that processing is performed every predetermined number of 2 or more with respect to the array order of each element of the first object 10. The first element, the Nth element, the N / 2th element, the N / 4th element, with respect to the arrangement order of each element (1 to N) of one object 10.
The processing order table NoTbl can be set so as to sequentially process the two-divided positions like the third N / 4th element.

In step S23, the processing order table NoTb
The element number no = NoTbl (i) for executing the process is acquired by referring to l. In step S24, the predetermined point 21 and the simple determination distance Drgh of the currently targeted no element are acquired. Similarly to the above, the maximum area coordinates Vmax (xma of FIG.
x, ymax, zmax) and minimum area coordinates Vmin (xmin, ymin, zmi
The distance between n) and the predetermined point 21 can be calculated, and the smaller one can be set as the simple determination distance Drgh.

In step S25, the simple determination distance Drgh
Is above the shortest distance Dmin. When it is determined that the simple determination distance Drgh exceeds the shortest distance Dmin, the process proceeds to step S23, and the simple determination distance Drgh
When it is determined that is less than the shortest distance Dmin, the process proceeds to step S26. At step S26, the predetermined point 21
And the no-th element 100 (no) are calculated in detail, and the element distance Dobj between the predetermined point 21 and the no-th element 100 (no) is acquired.

In step S27, it is determined whether the element distance Dobj is smaller than the shortest distance Dmin. Element distance Do
When it is determined that bj is smaller than the shortest distance Dmin, the process proceeds to step S28, and when it is determined that the element distance Dobj is equal to or more than the shortest distance Dobj, the process proceeds to step S23. In step S28, the value of the element distance Dobj is substituted for the shortest distance Dmin, and the data of the shortest distance Dmin is updated.

In step S29, the first object 1
It is determined whether or not the processing has been executed for all the elements of 0. If it is determined that some of the elements of the first object 10 have not been processed, the variable i is incremented and the same processing is executed for the next element. The processing order table NoTbl can be set so that the processing is executed every predetermined number in the arrangement order of the elements of the first object 10. For example, when processing is performed on the first object 10 in which the first element 101 to the fifteenth element 115 as shown in FIGS. 5 to 8 are arranged every fifth, a processing order table as shown in FIG. NoTbl can be set. In this case, the elements are arranged every 5th element from the first element 101 for the first time, and when the element 5th ahead exceeds the final element, the process returns to the 2nd element 102 and every 5th element thereafter. Are arranged.

Table 2 shows the number of times of processing when the models of FIGS. 5 to 8 are executed when the processing order table NoTbl is set every five times.

[0030]

[Table 2] When the processing order table NoTbl is set at every predetermined number, the number of detailed distance measurement processes is N when the number of elements of the first object 10 is N and the predetermined number is M,
The maximum value can be represented by (N / M + M) * K2. Here, K2 is a coefficient determined according to the type of shape of the first object 10 and the complexity of the shape.

In this way, the processing order table is set every predetermined number.
By setting NoTbl and executing the processing in accordance with the processing order table NoTbl, it is possible to reduce the number of times of detailed distance measurement processing, and it is possible to speed up the processing. The processing order table NoTbl is the first element, the Nth element, the (1+) th element in the arrangement order of the elements of the first object 10.
It is possible to set every two divisions in the order of N) / 2 elements.

For example, with respect to the first object 10 in which the first element 101 to the fifteenth element 115 are arranged as shown in FIGS.
After processing (N), the processing of the eighth element 108 ((1 + N) / 2) is executed, and further, the fourth element 104 ((1 + N) / 4) and the twelfth element (3 (1 + N) / 4) processing can be executed, and subsequent processing can be set to perform processing in the original array order.

When the processing order table NoTbl, which is a combination of the two-division order and the sequential processing, is set, the number of times each processing is performed when the model of FIGS. 5 to 8 is executed is shown in Table 3.
Shown in.

[0034]

[Table 3] A method of creating the processing order table NoTbl including the order of two divisions will be described with reference to FIGS. The data of each element included in the processing order table NoTbl is described using a linked list structure. Each of the data storage units 300 (1) to 300 (N) forming the processing order table NoTbl includes an ID storage unit 301 and a NEXT pointer 302. In the ID storage unit 301, the first object 10
Is stored, and the NEXT pointer 302 stores the data address of the element to be processed next. NEXT pointer 302 of final data storage unit 300 (N)
"END" is stored in (N).

Consider a case where the number N of elements of the first object 10 is 17. First, as shown in FIG. 13, the data of the first element (first) and the seventeenth element (final) of the first object 10 is set, and the NEXT pointer 3 of the first element is set.
The data address of the 17th element is stored in 02, and "END" is stored in the NEXT pointer of the 17th element. As a result, the processing order of the first element and the seventeenth element is set in the processing order table NoTbl.

Next, the data of the ninth element located between the first element and the seventeenth element is inserted. Here, the first
The NEXT pointer 302 of the element is updated to the data address of the ninth element, and the NEXT pointer 302 of the ninth element stores the data address of the seventeenth element. As a result, FIG.
As shown in 4, the processing order table NoTbl contains the first element,
The processing order of the ninth element and the seventeenth element is set.

Further, the data of the element located in the middle of each element is inserted. Here, the 5th element is inserted between the 1st element and the 9th element, and the 13th element is inserted between the 9th element and the 17th element. By updating the NEXT pointer 302 of each element, the processing order of each element as shown in FIG. 15 is set in the processing order table NoTbl. In this way, by repeatedly inserting the data until the difference between the element numbers of the adjacent elements becomes 1, the processing order table NoTbl can be set. Table 4 shows the decision order of each element at this time.
Shown in.

[0038]

[Table 4] Table 5 shows the number of detailed distance measurement processes when the shortest distance acquisition process is executed using the process order table NoTbl determined in this way.

[0039]

[Table 5] Here, the processing order of the processing order table NoTbl is shown on the horizontal axis, and the elements closest to the predetermined point 21 (inspection point) are the second element, the fourth element, the sixth element, the eighth element, the tenth element, and the first element.
The number of detailed distance measurements is calculated for each of the two elements, the fourteenth element, and the sixteenth element. However, predetermined point 2
When the element closest to 1 is the second element and the fourth element, and the next closest element is the third element, the element closest to the predetermined point 21 is the sixth element and the eighth element If the closest element is the seventh element, the element closest to the predetermined point 21 is the tenth element, and if the next closest element is the eleventh element for the twelfth element, the element closest to the predetermined point 21 is the first element. The case where the element next to the 14th element and the 16th element is the 15th element is considered.

As described above, the maximum value of the number of distance calculations when the processing order table NoTbl is composed of only the two-division order and does not include the sequential order can be represented by (log ₂ N + 2-3) * K3. Here, K3 is a coefficient determined according to the type of shape of the first object 10 and the complexity of the shape. The shortest distance between the predetermined point 21 and the first object 10 is calculated as described above. As a result, the processing time can be significantly shortened as compared with the case where the processing of the conventional detailed distance measurement is executed.

For each of the plurality of elements 201, 202, 203, ... Which constitute the second object 20,
By obtaining the shortest distance to the first object 10 using the same method, it is possible to obtain the shortest distance between the first object 10 and the second object 20, and in this case as well, the processing time is reduced. It can be shortened significantly.

Regarding the method for obtaining the shortest distance between the first object 10 and the second object 20 as described above,
This will be described based on the flowchart of FIG. In step S31, the shortest distance Dmin is set to a predetermined maximum value. Similarly to the above, the maximum value corresponding to the number of digits of the variable used for calculation can be set as a default value, and can be set to 1.0E + 38, for example.

In step S32, the first object 1
Processing order table NoTbl1 for determining the processing order for each element of 0 and processing order table NoTb for determining the processing order for each element of the second object
Create l2. The processing order tables NoTbl1 and NoTbl2 can be created in the same manner as the processing order table NoTbl described above.

In step S33, the processing order table NoTb
Element number no1 = NoT that executes processing by referring to l1 and NoTbl2
Acquires bl1 (i1), no2 = NoTbl2 (i2). Step S
At 34, the simple determination distances Drgh of the element number no1 and the element number no2 which are the current targets of the first object 10 and the second object 20, respectively, are acquired. Similar to the above, the maximum area coordinates Vmax (xmax, ymax,
zmax) and the minimum area coordinate Vmin (xmin, ymin, zmin), and the simple determination distance Drgh is calculated.

In step S35, the simple determination distance Drgh
Is above the shortest distance Dmin. When it is determined that the simple determination distance Drgh exceeds the shortest distance Dmin, the process proceeds to step S33, and the simple determination distance Drgh
When it is determined that is less than or equal to the shortest distance Dmin, the process proceeds to step S36. In step S36, the detailed distance between the no1 element 100 (no1) of the first object 10 and the no2 element 200 (no2) of the second object 20 is calculated, and the no1 element 100 (no1) and the no2 element 200 are calculated. (No2)
And obtain the element distance Dobj with.

In step S37, it is determined whether the element distance Dobj is smaller than the shortest distance Dmin. Element distance Do
When bj is determined to be smaller than the shortest distance Dmin, the process proceeds to step S38, and when it is determined that the element distance Dobj is equal to or greater than the shortest distance Dobj, the process proceeds to step S33. In step S38, the value of the element distance Dobj is substituted for the shortest distance Dmin, and the data of the shortest distance Dmin is updated.

In step S39, the second object 2
It is determined whether or not the processing has been executed for all the elements of 0. When it is determined that some of the elements of the second object 20 have not been processed, the variable i2 is incremented and the same processing is executed for the next element. If it is determined that the process has been executed for all the elements of the second object 20, the process proceeds to step S40.

In step S40, the first object 1
It is determined whether or not the processing has been executed for all the elements of 0. When it is determined that some of the elements of the first object 10 have not been processed, the variable i1 is incremented, the variable i2 is set to the initial value, and the same processing is executed for the next element. When it is determined that the processing has been completed for all the elements of the first object 10, this processing routine is ended and the current shortest distance D
The value of min is the first object 10 and the second object 2
Output as the shortest distance of 0.

[0049]

According to the present invention, when the shortest distance between objects is acquired, it is possible to reduce the number of detailed distance measurement processes, and it is possible to perform the shortest distance acquisition process at high speed. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a model in which a method for acquiring the shortest distance between objects according to the present invention is adopted.

FIG. 2 is an explanatory diagram showing an example of a model in which the shortest distance acquisition method between objects according to the present invention is adopted.

FIG. 3 is a flowchart of a conventional method.

FIG. 4 is an explanatory diagram of a simple determination process.

FIG. 5 is an explanatory diagram showing an example of a model in which the shortest distance acquisition method between objects according to the present invention is adopted.

FIG. 6 is an explanatory diagram showing an example of a model in which the shortest distance acquisition method between objects according to the present invention is adopted.

FIG. 7 is an explanatory diagram showing an example of a model in which the shortest distance acquisition method between objects according to the present invention is adopted.

FIG. 8 is an explanatory diagram showing an example of a model in which the shortest distance acquisition method between objects according to the present invention is adopted.

FIG. 9 is a flowchart according to one embodiment of the present invention.

FIG. 10 is an explanatory diagram showing an example of a processing order table.

FIG. 11 is an explanatory diagram showing an example of a processing order table.

FIG. 12 is an explanatory diagram of a link list structure.

FIG. 13 is an explanatory diagram showing a process of creating a processing order table based on a two-division order.

FIG. 14 is an explanatory diagram showing a process of creating a processing order table in the order of two divisions.

FIG. 15 is an explanatory diagram showing a process of creating a processing order table based on a two-division order.

FIG. 16 is a flowchart of a method for acquiring the shortest distance between polygons.

Claims (5)

[Claims] 1. A method for obtaining the shortest distance between objects for obtaining the shortest distance between an object composed of a plurality of elements and a predetermined point, the method comprising: A) setting the shortest distance Dmin to an initial value; B) determining a target element from a plurality of elements constituting the object based on a predetermined reading order different from the arrangement order, and reading the position information of the target element; and C) based on the position information of the target element. Then, the simple determination of the distance between the target element and the predetermined point and the setting of the simple determination distance Drgh is performed, and D) the simple determination distance Drgh is compared with the shortest distance Dmin, and the simple determination distance Drgh is the shortest distance Dmin. If it exceeds, the process proceeds to the B stage, and if the simple determination distance Drgh is the shortest distance Dmin or less, the distance between the target element and the predetermined point is determined in detail based on the position information of the target element, and the element distance is determined. D
E) comparing the element distance Dobj with the shortest distance Dmin, and if the element distance Dobj exceeds the shortest distance Dmin, shifts to the B step, and the element distance Dobj is equal to or shorter than the shortest distance Dmin. If there is, then the step of substituting the element distance Dobj into the shortest distance Dmin, and F) if there is any element that is not the target element among the plurality of elements that make up the object, move to step B, and A method of acquiring the shortest distance between objects, including the step of terminating the processing when the element of is determined to be the target element. 2. The method for acquiring the shortest distance between objects according to claim 1, wherein in the step B, the target elements are arranged every predetermined number a in the predetermined arrangement order (1 to N) of the number N of elements. 3. In the step B, 1, N, (1 + N) / 2, (1 + N) / 4,3 (1+) for a predetermined arrangement order (1 to N) of the number N of elements. N) / 4
The shortest distance acquisition method between objects according to claim 1, wherein the target element is determined in the order of. 4. The object comprises a plurality of polygon planes arranged in a three-dimensional space as elements.
The method for obtaining the shortest distance between objects according to any one of 1. 5. A method for obtaining the shortest distance between objects for obtaining the shortest distance between a first object and a second object composed of a plurality of elements, the method comprising: A) setting the shortest distance Dmin to an initial value. B) determining a first target element from a plurality of elements constituting the first object based on a predetermined reading order different from the arrangement order, and reading the position information of the first target element; and C). Determining a second target element from a plurality of elements forming the second object based on a predetermined reading order different from the arrangement order, and reading the position information of the second target element; D) the first target Easily determining the distance between the first target element and the second target element based on the positional information of the element and the second target element, and setting the distance to the simple determination distance Drgh; and E) the simple determination distance Drgh. The short distance Dmin is compared, and when the simple determination distance Drgh exceeds the shortest distance Dmin, the process shifts to the C stage, and when the simple determination distance Drgh is the shortest distance Dmin or less, the first target element A step of making a detailed determination of the distance between the first target element and the second target element based on the position information of the second target element and setting it as the element distance Dobj; If the distance Dobj exceeds the shortest distance Dmin, the process shifts to the step C; if the element distance Dobj is less than or equal to the shortest distance Dmin, the element distance Dobj is substituted for the shortest distance Dmin; If there is any element that does not become the second target element among the plurality of elements that make up the two objects, move to stage C. If it is determined that all the elements have become the second target element, go to stage H. H) the first object If there is any element that does not become the first target element among the plurality of elements that make up the object, the process moves to stage B, and if it is determined that all of the elements have become the first target element, the processing ends. A method for obtaining the shortest distance between objects including a step and a step.