JP3405827B2 - Graphic processing apparatus and intersection determination processing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphic processing apparatus for displaying a graphic according to the graphic data of a CAD system or the like, for example, using a graphic data created by another graphic processing apparatus. The present invention relates to a graphic processing device and an intersection determination processing method that prevent inconvenience in determining an intersection when performing processing.

[0002]

2. Description of the Related Art There are various types of graphic processing devices such as CAD systems, and generally there is no data compatibility between these devices. Therefore, when the graphic data created by another graphic processing device is used, the graphic data must be converted and used by using a translator or the like corresponding to each graphic processing device.

Normal graphic data is, as shown in FIG.
Each figure is composed of information such as point coordinates such as control points for specifying the figure and distances between points. However, in the figure data created by a certain figure processing device, for example, the positional relationship created as a tangent line may not be a tangent line in a strict sense in the figure data converted by a translator or the like and may be slightly separated. That is, it may not be recognized as an intersection (including a contact).

The problem regarding the disappearance of such intersections is due to the difference between single precision and double precision between the graphic processing devices, the difference in the method of holding the graphic data, the calculation error of the translator, etc., and the distance of the error is 、 It is safe to think that it is almost 0 in operation, but in actual calculation 10 ^-7 to 1
The distance may be about 0 ^-10 .

Therefore, in the conventional graphic processing apparatus, the intersection point is not found in the converted graphic data by an operation such as a hatching process or a trimming process that requires a closed region search. Inconvenience may have occurred.

FIG. 5 is a diagram for explaining the problems of the prior art. For example, it is assumed that there is graphic data (circle and spline curve) before conversion as shown in FIG. In FIG. 5A, the curve 1 and the curve 2 are in contact with the circle 1 and the circle 2, respectively, at two points. Here, when the trimming operation of cutting the curve with a circle is performed, as shown in FIG. 5B, a contact point A between the curve 1 and the circle 1, a contact point B between the curve 1 and the circle 2, and a contact point between the curve 2 and the circle 1. C,
The curve 2 is cut by trimming at the contact point D between the curve 2 and the circle 2.

However, when the graphic data shown in FIG. 5 (A) is converted by a translator for use in another graphic processing apparatus, the original data is converted into the original data as shown in FIG. 5 (C). The part that was in contact may be slightly separated. If the trimming operation of cutting the curve with a circle is performed on this converted data, the original contact point A,
At the points C and D, the intersection cannot be found, so trimming cannot be performed. Therefore, it is necessary to specify the cutting points one by one to cut the curve, which is time-consuming, and also, FIG.
It was difficult to make a clean shape as shown in.

Further, when there is a hatching instruction designating one point in the area X surrounded by the circle 1 and the circle 2 and the curve 1 and the curve 2, first, the intersection points A, B, C and D are checked to determine the closed area. Identify X. In the case shown in FIG. 5 (A), the intersection points A, B,
Since the closed region X can be specified by C and D, hatching processing can be performed. However, as shown in FIG. 5C, when the circle and the curve are separated by the conversion of the graphic data, it is determined that the intersections (contact points) A, C, and D do not exist, so that the closed region X can be specified. Therefore, accurate hatching could not be performed.

Therefore, in the case of FIG. 5C, a line is manually drawn at points A, C and D,
After correcting the circles and curves, the hatching operation was performed.

[0010]

Intersection point calculation in graphic processing is performed by solving geometrical elements such as curves and equations of geometrical elements using graphic data information. Therefore, when the distance between the elements is very small on the data, the intersection cannot be calculated. Therefore, although the distance between the elements is very small, there is a problem that the intersection cannot be calculated even if there is a point recognized as the intersection in operation.

In particular, when the graphic data created by a certain graphic processing device is converted by a translator or the like for use in another graphic processing device, the trimming and hatching operations that could originally be performed cannot be performed. There was a problem.

The present invention solves the above-mentioned problems, and when a plurality of line figures such as circles and spline curves exist in the vicinity, the intersection is generated and processed as an operation intersection, and the intersection calculation is strengthened. By doing so, it is intended to facilitate the graphic processing.

[0013]

FIG. 1 is a diagram showing a system configuration example of the present invention. In FIG. 1, 1 is a processing unit in which a CAD system including a CPU and a memory operates, 2 is a command processing unit, 3 is a handler unit, 4 is a graphic processing unit, 5 is a data storage unit, 6 is a display control unit, 7 Is a display device, 8 is an external storage device such as a disk device, 9 is an input device such as a keyboard or mouse, 11 is an intersection calculation processing means, 1
Reference numeral 2 represents an allowable value determination processing means, and 13 represents an intersection point setting processing means.

The command processing section 2 is a processing means for analyzing a command from the input device 9. The handler unit 3 is a processing unit that activates the graphic processing unit 4, activates the data storage unit 5, and the like according to the analysis result of the input command.
The data storage unit 5 is means for storing graphic data in the external storage device 8 and reading graphic data from the external storage device 8 according to an instruction from the handler unit 3. The display control unit 6 is a control unit that displays the graphic data created and edited by the graphic processing unit 4 on the display device 7.

The graphic processing section 4 is a processing means for creating / editing graphic data in the present CAD system, and is an essential part of the present invention, the intersection calculation processing means 11, the allowable value determination processing means 12, the intersection setting processing means 13. Equipped with.

The intersection calculation processing means 11 is means for calculating the intersections of a plurality of line figures. Allowable value determination processing means 12
Is a means for deciding whether or not the shortest distance between the line figures for which the intersection is obtained is within a predetermined allowable value when the intersection is not obtained by the calculation of the intersection calculation processing means 11.

The intersection point setting processing means 13 is means for setting a neighborhood point of the shortest distance of the line figure determined to be within the predetermined tolerance value by the tolerance value determination processing means 12 as an intersection point of two line figures.

[0018]

In the present invention, if the intersection is not obtained when the equation of the line figure is solved by the intersection calculation processing means 11, the allowable value judgment processing means 12 determines whether the elements are close to each other within the allowable value. If it is within a predetermined allowable value, the intersection point setting processing means 1 is checked by checking whether or not it is finally recognized as an intersection point in consideration of an error.
Set by 3 instead of the original intersection.

For example, since the graphic data created by another model is used, if the shortest distance between the line graphics whose intersections have not been found is within a predetermined allowable value in the graphic data converted by the translator. By setting the nearest point of the shortest distance as the intersection of two line figures, it is possible to perform operations such as hatching processing and trimming processing.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a flow chart of processing in the embodiment of the present invention. The process shown in FIG. 2 is executed when it is necessary to obtain the intersection of the line figures by the trimming or hatching operation in the figure processing unit 4 shown in FIG.

First, in the process of step S1, graphic data of a line graphic for which an intersection is to be obtained is input. In the process of step S2, the equations of a plurality of line figures representing curves and the like are solved based on the inputted figure data.

In the process of step S3, it is determined whether a solution has been obtained. If there is a solution, since there is an intersection, the process of step S4 is performed. If there is no solution, since there is no intersection, the process proceeds to step S5.

In the process of step S4, the intersection is calculated from the obtained solution, and the process proceeds to step S8. Step S
In the process of 5, it is checked whether or not the curve for which the intersection is to be obtained and the curve exist in the vicinity, and the distance L at which the elements are closest to each other is calculated.

In the processing of step S6, it is determined whether or not the distance L obtained in step S5 is within the range of a predetermined allowable value ε. Here, ε is not 0, but is a value extremely close to 0. If the distance L is within the range of the allowable value ε that can be approximated to 0, the process proceeds to step S7. If the distance L is outside the range of the allowable value ε that can be approximated to 0, the process of step S9 is performed.

In the process of step S7, the midpoint of the distance L obtained in the process of step S5 is generated as an intersection. In the process of step S8, the intersection obtained in the process of step S4 or the process of step S7 is set as the intersection information, and the process ends.

If the distance L is outside the range of the allowable value ε that can be approximated to 0 in the processing of step S6, no intersection is set in the processing of step S9, and the processing ends. In the conventional method, when it is determined that the solution of the equation cannot be obtained in step S3, no intersection is set immediately in step S9, whereas in the present embodiment, the elements are determined in steps S5 to S7. Unlike the prior art, the point of intersection is generated when the elements and are separated by only a very small distance.

FIG. 3 is a diagram showing graphic data to be processed in the embodiment. FIG. 3 is graphic data obtained by converting the graphic data consisting of the circle 1, the circle 2, the curve 1, and the curve 2 shown in FIG. 5A. As a result of the conversion, the curve 1, the circle 1, and the curve 2 Circle 1 and Circle 2 are no longer in contact,
The intersections A, C, and D in (A) disappear.

First, the equation representing the curve 1 and the circle 1 is solved (FIG. 2: step S2). As a result of determining the obtained solution (FIG. 2: step S3), since there is no solution in the equation of the curve 1 and the circle 1, the curve 1 and the circle 1 are shown in P1 which is the closest among the elements existing in the vicinity. The distance L of the part is calculated (FIG. 2:
In step S5), it is determined whether or not it can be regarded as 0 in operation (FIG. 2: step S6). When the distance L is a value close to 0, the midpoint of the distance L (or its neighboring point) is set as an intersection (FIG. 2: step S8).

Similarly, the above-mentioned intersection point calculation processing is performed for the curve 2 and the circle 1, and for the curve 2 and the circle 2, and P2 shown in the figure is obtained.
The closest middle point in the range of P3 is obtained and set as the intersection. By this, the point in P1, the point B, the point in P2,
The closed region X can be specified by the point in P3, and the hatching process and the trimming process can be performed.

[0030]

As described above, according to the present invention,
When the equation is solved in the process of calculation, the shortest distance is determined and the intersection point is set only when the intersection point between the line figures cannot be obtained. Therefore, the existing processing speed and processing result are not affected. , It is possible to strengthen the calculation of the intersections near the contact points, and to facilitate the creation and editing of figures. In actual operation, if the difference in distance that can be regarded as 0 is the same as the operation that can be performed with existing drawings created by other CAD systems, etc., the existing assets can be effectively used. .

Further, not only the converted graphic data, but also newly created graphic data can be improved in flexibility in determining intersections in a closed region search for trimming or hatching, and operability can be improved. Become.

[Brief description of drawings]

FIG. 1 is a diagram showing a system configuration example of the present invention.

FIG. 2 is a flowchart of a process in the embodiment.

FIG. 3 is a diagram showing an example of graphic data for explaining the processing of the embodiment.

FIG. 4 is a diagram showing an example of a format of general graphic data.

FIG. 5 is a diagram illustrating a problem of the conventional technique.

[Explanation of symbols]

1 Processor (CPU / Memory) 2 Command processing section 3 Handler part 4 Graphic processing unit 5 Data storage 6 Display control unit 7 Display 8 external storage 9 Input device 11 Intersection calculation processing means 12 Allowable value determination processing means 13 Intersection setting processing means

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Claims (2)

(57) [Claims] 1. A graphic processing device, which is provided with a display device for displaying a graphic and which performs drawing while displaying the graphic according to the graphic data, calculates an intersection of the two graphic lines by solving an equation representing the two graphic lines. and the intersection point calculation processing means for, when the intersection is not Motomara because there is no solution in the intersection calculation processing means, the shortest distance between the two linear drawing
Calculated, if the shortest distance calculated is determined a predetermined allowable value determination processing unit determines whether it is within the allowable value, and the allowable value determination processing means by Risho constant within tolerance , a line is the shortest distance between the two linear drawing
The midpoint of the minute is set as the intersection of the two line figures , and
It is judged by the allowable value judgment processing means that it is not within the predetermined allowable value.
A graphic processing device having an intersection setting processing means for setting no intersection when set. 2. A method for determining an intersection in a graphic processing device, which comprises a display device for displaying a graphic and displays the graphic according to the graphic data, by solving an equation expressing two line graphics. Figure
The intersection calculation process for calculating the intersection of the shapes and the intersection calculation process because there is no solution in the intersection calculation process.
If not, the shortest distance between the two line figures
Calculated, and whether the calculated shortest distance is within a predetermined allowable value
The allowable value judgment process for judging whether or not it was judged to be within the predetermined allowable value by the above-mentioned allowable value judgment process.
In this case, the line segment that is the shortest distance between the two line figures
Set the midpoint as the intersection of the two line figures and
It was judged by the value judgment process that it was not within the predetermined allowable value.
In this case, the intersection determination processing method is characterized by having an intersection setting processing step for setting no intersection.