JP4589369B2 - How to get the shortest distance between objects - Google Patents

Description

  The present invention relates to computer technology calculations such as CAD / CAM and CG, and more particularly to 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.

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 interference state between parts or manufacturing tools.
When the face of each object is expressed by a predetermined mathematical expression, the shortest distance between the objects can be calculated by analyzing the mathematical expression.

  Further, each object can be assumed to be a polyhedron, and can be decomposed into simple shape elements constituting the polyhedron, and the shortest distance can be obtained based on position information of each element.

When calculating the shortest distance by analyzing a mathematical expression expressing the face of each object, it is necessary to use a convergence calculation or the like.
When each object is decomposed into simple shape elements, the shortest distance between the polygons constituting each object is sequentially obtained based on the position information of the triangular polygons constituting the polyhedron.

The triangular polygon is composed of an edge indicating the boundary of the element, a vertex constituting the edge pair of the edge, and a face representing the face of the element. In general, the triangular polygons are divided in a geometrically continuous state, and the element data is generally arranged in an order based on the continuity.
Usually, since such polygon data is read in the order of arrangement and the shortest distance is calculated, 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.

  The shortest distance acquisition method between objects according to the present invention is a shortest distance acquisition method between objects for acquiring the shortest distance between an object composed of a plurality of elements and a predetermined point in computer graphics processing, A) a step of setting the shortest distance Dmin to an initial value; and B) an order of arrangement having geometric continuity of a plurality of elements constituting the object in an order of reading without geometric continuity. A step of determining a target element based on the target element and reading out the position information of the target element; and C) based on the position information of the target element, simple determination of the distance between the target element and the predetermined point is set to the simple determination distance Drgh Step D) The simple determination distance Drgh is compared with the shortest distance Dmin. If the simple determination distance Drgh exceeds the shortest distance Dmin, the process proceeds to the B stage, and the simple determination distance Drgh is the shortest distance Dm. If it is less than or equal to in, the step of determining in detail the distance between the target element and the predetermined point based on the position information of the target element and setting it to the element distance Dobj, and E) comparing the element distance Dobj with the shortest distance Dmin When the element distance Dobj exceeds the shortest distance Dmin, the process proceeds to step B, and when the element distance Dobj is equal to or less than the shortest distance Dmin, the step of substituting the element distance Dobj into the shortest distance Dmin; F) Including the step of moving to stage B when there are elements that are not the target elements among the plurality of elements constituting the object, and ending the process when it is determined that all the elements are the target elements .

Here, in the B stage, the reading is performed so that the target element becomes the target element every predetermined number a with respect to the predetermined arrangement order (1 to N) in consideration of the geometric continuity of the element having N elements constituting the object. The order can be stored as a processing order table, the target element can be determined by referring to the processing order table, and the position information of the target element can be read.
In addition, a method for obtaining the shortest distance between objects according to another aspect of the present invention provides a method for obtaining the shortest distance between a first object and a second object composed of a plurality of elements in a computer graphics process. And A) a step of setting the shortest distance Dmin to an initial value, and B) a predetermined arrangement order considering geometric continuity of elements of a predetermined number of elements constituting the first object. Then, the reading order that becomes the target element every predetermined number is stored as the first processing order table, the first target element is determined by referring to the first processing order table, and the position information of the first target element is obtained. In the reading step, and C) a predetermined arrangement order that takes into account the geometric continuity of the elements of the predetermined number of elements constituting the second object so that the elements become target elements every predetermined number. Storing a reading order as a second processing table, referring to the second processing order table, determining a second target element and reading position information of the second target element; and D) a first target element and a second A step of simply determining the distance between the first target element and the second target element based on the position information of the target element and setting the distance to the simple determination distance Drgh, and E) comparing the simple determination distance Drgh and the shortest distance Dmin When the simple determination distance Drgh exceeds the shortest distance Dmin, the process proceeds to the C stage. When the simple determination distance Drgh is equal to or less than the shortest distance Dmin, the position information of the first target element and the second target element is displayed. A step of determining the distance between the first target element and the second target element in detail and setting the distance to the element distance Dobj, and F) comparing the element distance Dobj with the shortest distance Dmin, so that the element distance Dobj exceeds the shortest distance Dmin If so, move to stage C When the distance Dobj is less than or equal to the shortest distance Dmin, a step of substituting the element distance Dobj into the shortest distance Dmin, and G) some of the plurality of elements constituting the second object are not the second target element. In the case, the process proceeds to the C stage, and when it is determined that all the elements have become the second target elements, the process proceeds to the H stage, and H) the first target among the plurality of elements constituting the first object When there is an element that is not an element, the process proceeds to stage B. When it is determined that all the elements have become the first target element, the process is terminated.

  A program according to the present invention is a program for causing a computer to perform a method for obtaining a shortest distance between objects for obtaining a shortest distance between an object composed of a plurality of elements and a predetermined point. A step of setting Dmin to an initial value; and B) a target element based on a reading order having no geometric continuity with respect to an array having an array order having a geometric continuity of a plurality of elements constituting the object. A step of reading the position information of the target element, C) a step of simply determining the distance between the target element and the predetermined point based on the position information of the target element, and setting the simple determination distance Drgh; ) The simple judgment distance Drgh is compared with the shortest distance Dmin. If the simple judgment distance Drgh exceeds the shortest distance Dmin, the process proceeds to stage B. If the simple judgment distance Drgh is less than the shortest distance Dmin, A step of determining in detail the distance between the target element and the predetermined point based on the position information of the elephant element and setting it as the element distance Dobj; E) comparing the element distance Dobj with the shortest distance Dmin, 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; and F) a plurality of elements constituting the object. A method for obtaining the shortest distance between objects includes a step B when there is an element that is not a target element, and a step of ending the process when it is determined that all elements are a target element. A program for causing a computer to execute.

  Furthermore, a program according to another aspect of the present invention is a program for causing a computer to perform 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. A) a step of setting the shortest distance Dmin to an initial value; and B) target elements every predetermined number with respect to a predetermined arrangement order considering geometric continuity of elements of a predetermined number of elements constituting the first object. And a step of reading the position information of the first target element by determining the first target element by referring to the first processing order table, and C) second With respect to the predetermined arrangement order in consideration of the geometric continuity of the elements of the predetermined number of elements constituting the object, the reading order that becomes the target elements every predetermined number is the second processing table. A step of determining the second target element by referring to the second processing order table and reading the position information of the second target element, and D) based on the position information of the first target element and the second target element The step of simply determining the distance between the first target element and the second target element and setting the distance to the simple determination distance Drgh, E) comparing the simple determination distance Drgh with the shortest distance Dmin, and the simple determination distance Drgh is the shortest If the distance Dmin is exceeded, the process proceeds to stage C. If the simple determination distance Drgh is equal to or shorter than the shortest distance Dmin, the first target element and the second target element are determined based on the position information of the first target element and the second target element. The step of determining the distance of the second target element in detail and setting it to the element distance Dobj, and F) comparing the element distance Dobj with the shortest distance Dmin, and if the element distance Dobj exceeds the shortest distance Dmin, The element distance Dobj is less than the shortest distance Dmin In some cases, the step of substituting the element distance Dobj for the shortest distance Dmin, and G) if there is a plurality of elements constituting the second object that are not the second target element, the process proceeds to the C stage. When it is determined that all the elements have become the second target element, there are stages that shift to the H stage, and H) there are elements that are not the first target element among the plurality of elements that constitute the first object. The program for causing the computer to execute the method for obtaining the shortest distance between objects including the stage B in the case where all elements have become the first target element and the process is terminated when it is determined that all elements have become the first target elements. is there.

  According to the present invention, when the shortest distance between objects is acquired, the number of detailed distance measurement processes can be reduced, and the shortest distance acquisition process can be performed at high speed.

The method for obtaining the shortest distance between objects according to the present invention is installed as a part of a computer application that performs graphics processing such as CAD / CAM and CG, and one embodiment thereof will be described below.
Consider a case where the shortest distance between the first object 10 and the second object 20 is acquired as shown in FIG.

  The illustrated first object 10 and second object 20 are each composed of a polyhedron having a continuous polygon plane. The first object 10 includes a first element 101 that is a triangular polygon, a second element 102, a third element 103, and so on. Similarly, the second object 20 is also a first element 201 that is a triangular polygon, It is assumed that the second element 202, the third element 203,...

  Position information of the first element 101, the second element 102, the third element 103,... Of the first object 10 is arranged in a predetermined arrangement order in consideration of geometric continuity. The data array is configured such that adjacent elements are sequentially aligned from the first element 101 located at the lower left of 1. Similarly, the position information of the first element 201, the second element 202, the third element 203,... Of the second object 20 is also arranged in a predetermined arrangement order in consideration of geometric continuity. For example, the data array is configured such that adjacent elements are sequentially aligned from the first element 201 located at the upper right in FIG.

  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 set to each element of the first object 10. The calculation is performed in the order of arrangement, and the shortest is the provisional shortest distance between objects. Furthermore, the distance from the second element 202, which is the next element of the second object 20, to the second object 10 is calculated in the order of arrangement of the elements of the first object 10, and the value is smaller than the provisional shortest distance. If there is something, update the data sequentially.

In this way, the process 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 description, a case where the shortest distance between a predetermined point and an object is obtained will be considered.
As shown in FIG. 2, the first object 10 is composed of a first element 101, a second element 102, a third element 103... As in FIG. 1, and a predetermined point 21 on the second object. Consider a case in which the shortest distance from the first object 10 is acquired.

A conventional example of a 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 the calculation can be set as the default value, for example, 1.0E + 38.

In step S12, the simple determination distance Drgh from the predetermined point 21 to the i-th element 100 (i) that is the current target is acquired.
As shown in FIG. 4, the i-th element 100 (i) of the first object 10 has three vertices V1 (x1, y2, z3), V2 (x2, y2, z2), and V3 (x3, y3, z3). , 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 set as the simple determination distance Drgh.

In step S13, it is determined whether or not the simple determination distance Drgh exceeds the shortest distance Dmin. If it is determined that the simple determination distance Drgh exceeds the shortest distance Dmin, the process proceeds to step S12. If it is determined that the simple determination distance Drgh is equal to or less than the shortest distance Dmin, the process proceeds to step S14.
In step S14, a detailed distance between the predetermined point 21 and the i-th element 100 (i) is calculated, and an element distance Dobj between the predetermined point 21 and the i-th element 100 (i) is acquired. Here, the method of acquiring the distance between the predetermined point 21 and the i-th element 100 (i) is performed using various proposed methods, and details thereof are not mentioned here.

In step S15, it is determined whether or not the element distance Dobj is smaller than the shortest distance Dmin. If it is determined that the element distance Dobj is smaller than the shortest distance Dmin, the process proceeds to step S16. If it is determined that the element distance Dobj is greater than or equal to the shortest distance Dobj, the process proceeds to step S12.
In step S16, the value of the element distance Dobj is substituted into the shortest distance Dmin, and the data of the shortest distance Dmin is updated.

In step S <b> 17, it is determined whether or not processing has been executed for all elements of the first object 10. When it is determined that there is an element that has not been processed among the elements of the first object 10, the variable i is incremented and the same process is performed for the next element.
As described above, when the processing is executed in the order of arrangement of each element of the first object 10, there is 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 top of each element of the first object 10 is the shortest, the detailed distance measurement is performed at the first step. It is only necessary to process only one element 101.
However, as shown in FIG. 6, when the distance to the first element 101 arranged at the top of each element of the first object 10 is the maximum, and the distance of each element is sequentially shortened in the arrangement order. Requires detailed distance measurements for all elements.

Further, as shown in FIG. 7, detailed distance measurement is performed when the distance to the fifth element 105 is the shortest and when the distance to the tenth element 110 is the shortest as shown in FIG. The number of processing is different.
Table 1 shows the number of times of processing when the shortest distance is acquired for each of the models shown in FIGS.

The average value of the number of detailed distance measurement processes in such a sequential distance acquisition method can be expressed as (N / 2) * K1, where N is the number of elements of the first object 10. Here, K1 is a coefficient determined according to the shape type and shape complexity of the first object 10.
A flowchart of the method for obtaining the shortest distance between objects according to the present invention is shown in FIG.
In step S21, 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 the calculation can be set as the default value, for example, 1.0E + 38.

  In step S22, a processing order table NoTbl for determining the processing order is created for each element of the first object 10. The processing order table NoTbl can be created, for example, by setting the processing order table NoTbl so that processing is performed every two or more predetermined numbers with respect to the arrangement order of the elements of the first object 10. 2 division positions like 1st element, Nth element, N / 2th element, N / 4th element, 3rd N / 4 element, etc. 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 process sequentially.

In step S23, the element number no = NoTbl (i) for executing the processing is acquired with reference to the processing order table NoTbl.
In step S24, the simple determination distance Drgh between the predetermined point 21 and the current target no-element is acquired. In the same manner as described above, the distance between the maximum area coordinate Vmax (xmax, ymax, zmax) and the minimum area coordinate Vmin (xmin, ymin, zmin) in FIG. 4 and the predetermined point 21 is calculated, and the smaller one is simply determined. The distance Drgh can be set.

In step S25, it is determined whether or not the simple determination distance Drgh exceeds 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 when it is determined that the simple determination distance Drgh is equal to or less than the shortest distance Dmin, the process proceeds to step S26.
In step S26, a detailed distance between the predetermined point 21 and the no-th element 100 (no) is calculated, and an element distance Dobj between the predetermined point 21 and the no-th element 100 (no) is obtained.

In step S27, it is determined whether or not the element distance Dobj is smaller than the shortest distance Dmin. If it is determined that the element distance Dobj is smaller than the shortest distance Dmin, the process proceeds to step S28. If it is determined that the element distance Dobj is equal to or greater than the shortest distance Dobj, the process proceeds to step S23.
In step S28, the value of the element distance Dobj is substituted into the shortest distance Dmin, and the data of the shortest distance Dmin is updated.

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

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

When the processing order table NoTbl is set for every predetermined number, the number of detailed distance measurement processes is N (the number of elements of the first object 10 and M is the predetermined number). M + M) * K2. Here, K2 is a coefficient determined according to the shape type and shape complexity of the first object 10.
In this way, by setting the processing order table NoTbl every predetermined number and executing processing along this processing order table NoTbl, it is possible to reduce the number of detailed distance measurement processing, and speed up the processing. Can be planned.

The processing order table NoTbl is set every two divisions in the order of the first element, the Nth element, the (1 + N) / 2 element, etc. with respect to the arrangement order of the elements of the first object 10. Is possible.
For example, after processing the first element 101 and the fifteenth element 115 (N) on the first object 10 in which the first element 101 to the fifteenth element 115 are arranged as shown in FIGS. The process of 8 elements 108 ((1 + N) / 2) is executed, and further, the process of 4th element 104 ((1 + N) / 4) and 12th element (3 (1 + N) / 4) The subsequent processing can be set to be performed in the original arrangement order.

  Table 3 shows the number of times of processing when the model shown in FIGS. 5 to 8 is executed when the processing order table NoTbl that combines the two-part dividing order and the sequential processing is set.

A method of creating the processing order table NoTbl including the two division order will be described with reference to FIGS.
Data of each element included in the processing order table NoTbl is described using a link list structure. Each of the data storage units 300 (1) to 300 (N) constituting the processing order table NoTbl includes an ID storage unit 301 and a NEXT pointer 302, respectively. The ID storage unit 301 stores the element number of the first object 10, and the NEXT pointer 302 stores the data address of the element to be processed next. “END” is stored in the NEXT pointer 302 (N) of the final data storage unit 300 (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 are set, and the data address of the seventeenth element is stored in the NEXT pointer 302 of the first element. , “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 NEXT pointer 302 of the first element is updated to the data address of the ninth element, and the data address of the seventeenth element is stored in the NEXT pointer 302 of the ninth element. As a result, as shown in FIG. 14, the processing order of the first element, the ninth element, and the seventeenth element is set in the processing order table NoTbl.

Furthermore, the data of the element located in the middle between each element is inserted. Here, the fifth element is inserted between the first element and the ninth element, and the thirteenth element is inserted between the ninth element and the seventeenth 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, the processing order table NoTbl can be set by repeating data insertion until the difference between the element numbers of adjacent elements becomes 1. Table 4 shows the determination order of each element at this time.

  Table 5 shows the detailed distance measurement processing count when the shortest distance acquisition processing is executed using the processing order table NoTbl determined as described above.

  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 twelfth element. The number of detailed distance measurements is calculated for each of the element, the 14th element, and the 16th element. However, when the element closest to the predetermined point 21 is the second element and the fourth element, when the next closest element is the third element, the elements closest to the predetermined point 21 are the sixth element and the eighth element. When the next closest element is the seventh element, the element closest to the predetermined point 21 is the tenth element, and when the next closest element is the eleventh element, the element closest to the predetermined point 21 The case where the next closest element is the fifteenth element is considered with respect to the element whose closest element is the fourteenth element and the sixteenth element.

Thus, the maximum value of the number of distance calculations in the case where the processing order table NoTbl is composed of only two division orders 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 shape type and the complexity of the shape of the first object 10. As described above, the shortest distance between the predetermined point 21 and the first object 10 is calculated. As a result, the processing time can be significantly reduced as compared with the case of executing the conventional sequential detailed distance measurement process.

The first object 10 and the second object 20 are obtained by obtaining the shortest distance to the first object 10 using a similar method for each of the plurality of elements 201, 202, 203. It is possible to acquire the shortest distance between the two, and also in this case, the processing time can be greatly shortened.
A method for obtaining the shortest distance between the first object 10 and the second object 20 will be described with reference to 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 the calculation can be set as the default value, for example, 1.0E + 38.
In step S32, a processing order table NoTbl1 for determining the processing order for each element of the first object 10 and a processing order table NoTbl2 for determining the processing order for each element of the second object are created. 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, element numbers no1 = NoTbl1 (i1) and no2 = NoTbl2 (i2) to be processed are acquired with reference to the processing order tables NoTbl1 and NoTbl2.
In step S34, the simple determination distance 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, is acquired. In the same manner as described above, the simple determination distance Drgh is calculated based on the maximum area coordinate Vmax (xmax, ymax, zmax) and the minimum area coordinate Vmin (xmin, ymin, zmin) of each element.

In step S35, it is determined whether or not the simple determination distance Drgh exceeds 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 when it is determined that the simple determination distance Drgh is equal to or less than the shortest distance Dmin, the process proceeds to step S36.
In step S36, a detailed distance between the first no1 element 100 (no1) of the first object 10 and the second no2 element 200 (no2) of the second object 20 is calculated, and the first no1 element 100 (no1) and the second no2 element 200 are calculated. The element distance Dobj with (no2) is acquired.

In step S37, it is determined whether or not the element distance Dobj is smaller than the shortest distance Dmin. If it is determined that the element distance Dobj is smaller than the shortest distance Dmin, the process proceeds to step S38. If it is determined that the element distance Dobj is greater than or equal to the shortest distance Dobj, the process proceeds to step S33.
In step S38, the value of the element distance Dobj is substituted into the shortest distance Dmin, and the data of the shortest distance Dmin is updated.

  In step S39, it is determined whether or not processing has been executed for all elements of the second object 20. If it is determined that there is an element that has not been processed among the elements of the second object 20, the variable i2 is incremented and the same process is performed for the next element. On the other hand, when 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, it is determined whether or not processing has been executed for all elements of the first object 10. If it is determined that there is an element that has not been processed among the elements of the first object 10, the variable i1 is incremented and the variable i2 is set to an initial value, and the same process is performed for the next element. If 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 value of the current shortest distance Dmin is output as the shortest distance between the first object 10 and the second object 20. .

  According to the present invention, when acquiring the shortest distance between objects, the number of detailed distance measurement processes can be reduced, and the shortest distance acquisition process can be performed at high speed. In the processing, it can be used to obtain the shortest distance between an object composed of a plurality of elements and a predetermined point or the shortest distance between a plurality of objects.

Explanatory drawing which shows the example of the model by which the shortest distance acquisition method between the objects which concern on this invention is employ | adopted. Explanatory drawing which shows the example of the model by which the shortest distance acquisition method between the objects which concern on this invention is employ | adopted. The flowchart of a conventional method. Explanatory drawing of a simple determination process. Explanatory drawing which shows the example of the model by which the shortest distance acquisition method between the objects which concern on this invention is employ | adopted. Explanatory drawing which shows the example of the model by which the shortest distance acquisition method between the objects which concern on this invention is employ | adopted. Explanatory drawing which shows the example of the model by which the shortest distance acquisition method between the objects which concern on this invention is employ | adopted. Explanatory drawing which shows the example of the model by which the shortest distance acquisition method between the objects which concern on this invention is employ | adopted. 3 is a flowchart according to an embodiment of the present invention. Explanatory drawing which shows an example of a process order table. Explanatory drawing which shows an example of a process order table. Explanatory drawing of a link list structure. Explanatory drawing which shows the preparation process of the process order table by 2 division order. Explanatory drawing which shows the preparation process of the process order table by 2 division order. Explanatory drawing which shows the preparation process of the process order table by 2 division order. The flowchart of the method of acquiring the shortest distance between polygons.

Claims (5)

In computer graphics processing, 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,
A) setting the shortest distance Dmin to an initial value;
B) determining a target element every predetermined number with respect to an array in an array order having geometric continuity of a plurality of elements constituting the object, and reading position information of the target element;
C) Simple determination of the distance between the target element and the predetermined point based on the position information of the target element, and setting the simple determination distance Drgh;
D) The simple judgment distance Drgh is compared with the shortest distance Dmin. If the simple judgment distance Drgh exceeds the shortest distance Dmin, the process proceeds to stage B, and the simple judgment distance Drgh is equal to or less than the shortest distance Dmin. Is a step of determining in detail the distance between the target element and the predetermined point based on the position information of the target element and setting the distance to the element distance Dobj;
E) The element distance Dobj is compared with the shortest distance Dmin. If the element distance Dobj exceeds the shortest distance Dmin, the process proceeds to stage B. If the element distance Dobj is less than the shortest distance Dmin, Substituting the distance Dobj into the shortest distance Dmin;
F) When there is a plurality of elements constituting the object that are not the target elements, the process proceeds to the B stage, and when it is determined that all the elements are the target elements, the process is terminated. When,
To get the shortest distance between objects including Step B is
A processing order in which the order of all elements is replaced without thinning out the elements with respect to a predetermined arrangement order (1 to N) in consideration of the geometric continuity of N elements constituting the object. The method for obtaining the shortest distance between objects according to claim 1, wherein the method is stored as a table, the target element is determined by referring to the processing order table, and the position information of the target element is read out. In a computer graphics process, a method for obtaining a shortest distance between objects for obtaining a shortest distance between a first object and a second object composed of a plurality of elements,
A) setting the shortest distance Dmin to an initial value;
B) A first processing order table stores a reading order that becomes a target element at every predetermined number of the predetermined arrangement order in consideration of geometric continuity of elements of a predetermined number of elements constituting the first object. Determining the first target element by referring to the first processing order table and reading the position information of the first target element;
C) A reading order that becomes a target element at every predetermined number is stored as a second processing table with respect to a predetermined arrangement order that takes into account the geometric continuity of elements of a predetermined number of elements that constitute the second object. Determining a second target element by referring to the second processing order table and reading position information of the second target element;
D) A step of 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 and setting the distance to the simple determination distance Drgh;
E) The simple determination distance Drgh is compared with the shortest distance Dmin. If the simple determination distance Drgh exceeds the shortest distance Dmin, the process proceeds to the C stage, and the simple determination distance Drgh is equal to or less than the shortest distance Dmin. Determining in detail the distance between the first target element and the second target element based on the positional information of the first target element and the second target element and setting the distance to the element distance Dobj;
F) The element distance Dobj is compared with the shortest distance Dmin. If the element distance Dobj exceeds the shortest distance Dmin, the process proceeds to stage C. If the element distance Dobj is less than the shortest distance Dmin, Substituting the distance Dobj into the shortest distance Dmin;
G) When there is a plurality of elements constituting the second object that are not the second target elements, the process proceeds to the C stage, and it is determined that all the elements are the second target elements. Is the stage to move to the H stage,
H) When there is a plurality of elements constituting the first object that are not the first target element, the process proceeds to stage B, and it is determined that all the elements have become the first target element. Ends the process,
To get the shortest distance between objects including A program for causing a computer to perform a method for obtaining a shortest distance between objects for obtaining a shortest distance between an object composed of a plurality of elements and a predetermined point,
A) setting the shortest distance Dmin to an initial value;
B) determining a target element every predetermined number with respect to an array in an array order having geometric continuity of a plurality of elements constituting the object, and reading position information of the target element;
C) Simple determination of the distance between the target element and the predetermined point based on the position information of the target element, and setting the simple determination distance Drgh;
D) The simple judgment distance Drgh is compared with the shortest distance Dmin. If the simple judgment distance Drgh exceeds the shortest distance Dmin, the process proceeds to stage B, and the simple judgment distance Drgh is equal to or less than the shortest distance Dmin. Is a step of determining in detail the distance between the target element and the predetermined point based on the position information of the target element and setting the distance to the element distance Dobj;
E) The element distance Dobj is compared with the shortest distance Dmin. If the element distance Dobj exceeds the shortest distance Dmin, the process proceeds to stage B. If the element distance Dobj is less than the shortest distance Dmin, Substituting the distance Dobj into the shortest distance Dmin;
F) When there is a plurality of elements constituting the object that are not the target elements, the process proceeds to the B stage, and when it is determined that all the elements are the target elements, the process is terminated. When,
A program for causing a computer to execute a method for obtaining the shortest distance between objects including a computer. A program for causing a computer to perform a shortest distance acquisition method between objects for acquiring a shortest distance between a first object and a second object composed of a plurality of elements,
A) setting the shortest distance Dmin to an initial value;
B) A first processing order table stores a reading order that becomes a target element at every predetermined number of the predetermined arrangement order in consideration of geometric continuity of elements of a predetermined number of elements constituting the first object. Determining the first target element by referring to the first processing order table and reading the position information of the first target element;
C) A reading order that becomes a target element at every predetermined number is stored as a second processing table with respect to a predetermined arrangement order that takes into account the geometric continuity of elements of a predetermined number of elements that constitute the second object. Determining a second target element by referring to the second processing order table and reading position information of the second target element;
D) A step of 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 and setting the distance to the simple determination distance Drgh;
E) The simple determination distance Drgh is compared with the shortest distance Dmin. If the simple determination distance Drgh exceeds the shortest distance Dmin, the process proceeds to the C stage, and the simple determination distance Drgh is equal to or less than the shortest distance Dmin. Determining in detail the distance between the first target element and the second target element based on the positional information of the first target element and the second target element and setting the distance to the element distance Dobj;
F) The element distance Dobj is compared with the shortest distance Dmin. If the element distance Dobj exceeds the shortest distance Dmin, the process proceeds to stage C. If the element distance Dobj is less than the shortest distance Dmin, Substituting the distance Dobj into the shortest distance Dmin;
G) When there is a plurality of elements constituting the second object that are not the second target elements, the process proceeds to the C stage, and it is determined that all the elements are the second target elements. Is the stage to move to the H stage,
H) When there is a plurality of elements constituting the first object that are not the first target element, the process proceeds to stage B, and it is determined that all the elements have become the first target element. Ends the process,
A program for causing a computer to execute a method for obtaining the shortest distance between objects including a computer.

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