JP2006201837A - Image processor, program used therefor and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To create image data used for outputting line drawings, such as illustrations which are simple and of which fillet part can be easily recognized based on the data indicating a three-dimensional shape including the fillet part. <P>SOLUTION: The fillet face included in a model is expressed by a simplified fillet line as one ridge line by making a solid model managed under a 3D database 20 as a treating object. A fillet line generation part 113 creates a fillet line segment which presents the fillet face as a simple line drawing according to the type (1. boundary curve of a fillet part; 2. line segment of the fillet part center; 3. line segment having specified normal vector/angle) of the fillet line specified at an information input part 111 and numerical information, such as coefficients used for creating the fillet line on the basis of the information on the fillet face extracted at a fillet extraction part 115. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to processing of image data performed when data representing a three-dimensional shape used for CAD or the like (hereinafter referred to as “3D data” or “3D CAD data”) is used for an illustration or the like. The present invention relates to an image processing apparatus, a program used for the apparatus, and an image processing method, which make it possible to generate a fillet line for line drawing output representing a fillet portion from target 3D data.

Today, CAD (Computer Aided Design) is used for research and development in various fields. Especially, 3D CAD data that can represent real events is designed, and 3D models are designed, and the results of model design are actually researched and developed. The method of reflecting in the solution of the problem is used.
In the case of product design using CAD, 3D CAD data is used not only for design but also for illustrations (instructions and illustrations expressed in simplified diagrams) of product instructions, procedures, manuals, etc. It is generally used for creation, and by using such a method, it is possible to save time and effort for creating an illustration.
Since the 3D CAD data used for product design has detailed data, the minute detailed shape of the 3D CAD data may interfere with the illustration when used for the illustration. For this reason, when creating an illustration diagram, a method is adopted in which the shape of the other parts is simplified and expressed while leaving the degree of detail only in the parts that are the points of explanation.
There is a fillet part as a part to be simplified. FIG. 1 shows an example of a solid model SM having a fillet portion. In FIG. 1, a surface FL obtained by rounding a corner portion where the surface F1 and the surface F2 intersect is a fillet portion.
As for the process for obtaining the 3D data of the fillet portion, conventional examples shown in the following Patent Documents 1 and 2 can be shown. The fillet data processing method described in Patent Document 1 calculates the R vertex line and R deadline of the fillet surface based on the point cloud data obtained by actually measuring the clay model, calculates the fillet surface from these, and calculates the efficiency from the measured point cloud data. It is a method to create surface data well. In addition, the three-dimensional shape processing method for generating a fillet surface in Patent Document 2 specifies a common ridge line and a rounding radius of a pair of two surfaces that form a corner part for creating a fillet surface, and sets the specified ridge line. The two curved surfaces are smoothly connected with a specified rounding radius and swept so as to be related to a method of forming a fillet surface, and it is possible to detect interference (intersection) between fillet surfaces. Is.

The fillet portion is generally expressed by a narrow curved surface that can sweep an arc (sweep the inscribed circles on the surface F1 and the surface F2 in FIG. 1) as shown in Patent Document 2 illustrated as an example. In 3D CAD data, a ridge line surrounding a fillet portion is usually defined.
Therefore, when creating an illustration, a simple diagram can be created by representing this ridgeline on the diagram. According to this creation method, the fillet portion is drawn as an adjacent line segment at a minute distance. FIG. 12 shows an example of an illustration of the solid model SM12. In the case of FIG. 12, the solid model SM12 has a stepped surface, and the corners of the irregularities formed by the horizontal and vertical surfaces are the fillet portions FL, and the illustration of the fillet portion shows ridge lines L1, L2 surrounding the fillet portion FL. , L3, L4.
As another method for creating an illustration from 3D CAD data, there is a method for obtaining a diagram as shown in FIG. FIG. 13 shows a solid model SM13 having the same shape as that shown in FIG. 12, but the ridgelines L1 and L2 shown in FIG. 12 are omitted.
In the creation of the illustration of FIG. 13, the ridge line (boundary line) surrounding the fillet portion can be omitted based on the relationship between the normal vectors of the surfaces on both sides of the ridge line. That is, when the normal vectors of the surfaces on both sides of the ridge line are the same, the ridge line is smoothly connected. Therefore, the ridge line is omitted and the drawing is not performed. When this method is applied to the fillet portion, the boundary line where the fillet portion is smoothly connected is omitted, and the ridgelines L1 and L2 surrounding the fillet portion shown in FIG. 12 are not drawn, and a simple display can be obtained.
JP 2003-216881 A JP 2001-290850 A

However, the figure representing the ridgelines L1 and L2 surrounding the fillet portion of the solid model SM12 shown in FIG. 12 is too fine as an illustration because the fillet surface is originally a narrow curved surface, which is complicated. Moreover, although the figure which abbreviate | omits the ridgelines L1 and L2 surrounding the fillet part of solid model SM13 shown in FIG. 13 can obtain a simple display, it becomes difficult to recognize as a fillet part.
Up to now, even if such problems are recognized, no effective proposal has been made to solve them. In addition, even if the said patent documents 1 and 2 show about the process for creating 3D data of a fillet part, it does not show the method for creating the illustration figure of a fillet part based on 3D data. .
The present invention has been made in order to solve the above-described problems that occur in the above-described conventional technique for creating an illustration of a fillet part based on 3D data. The problem to be solved is three-dimensional including a fillet part. An image processing apparatus capable of generating image data used for line drawing output such as an illustration diagram that is simple and easy to recognize a fillet part based on data representing a shape, a program used for the apparatus, and an image processing method It is to provide.

  The invention according to claim 1 is an image processing apparatus capable of generating line drawing output data having a three-dimensional shape based on data representing the three-dimensional shape, and the data representing the fillet portion from the data representing the three-dimensional shape to be processed. A fillet part extracting means for extracting a fillet, and a fillet for generating one line segment data of a ridge line constituting a fillet surface as a fillet line for line drawing output expressing the fillet part based on the extracted fillet part data An image processing apparatus including a line generation unit.

According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, the fillet line generating unit is a unit that uses the generated single line segment as a boundary curve of a data fillet surface. To do.
According to a third aspect of the present invention, in the image processing apparatus according to the first aspect, the fillet line generating means is a means for making the one line segment to be generated a curve passing through the center of the fillet surface. It is what.
According to a fourth aspect of the present invention, in the image processing apparatus according to the first aspect, the fillet line generating means is configured to determine that the normal vector on the fillet plane is oriented in a predetermined direction with respect to the one line segment to be generated. It is characterized in that it is a means for making a passing line segment.

5. The image processing apparatus according to claim 1, further comprising a processing condition input unit that inputs processing conditions for generating line drawing output data of the fillet portion. The one line segment is defined as one of a boundary curve of the data fillet surface, a curve passing through the center of the fillet surface, and a line segment passing through the point where the normal vector on the fillet surface makes a specified direction. In other words, it is a means for executing one line segment generation process designated by the processing condition input means.
A sixth aspect of the present invention is the image processing apparatus according to any one of the first to fifth aspects, further comprising processing condition input means for inputting a processing condition for generating line drawing output data of the fillet portion. The generation means is a means for changing the length of the one line segment to be generated in accordance with the coefficient designated by the processing condition input means.

A seventh aspect of the present invention is a program for causing a computer to function as a fillet part extracting unit and a fillet line generating unit included in the image processing apparatus according to any one of the first to sixth aspects.
The invention according to claim 8 is an image processing method capable of generating line drawing output data having a three-dimensional shape based on data representing the three-dimensional shape. Data representing the fillet portion is represented by data representing the three-dimensional shape to be processed. And a step of generating one line segment data of the ridge line constituting the fillet surface as a fillet line for line drawing output expressing the fillet portion based on the extracted fillet portion data An image processing method characterized by the above.

  According to the present invention, when performing image processing capable of generating line drawing output data of a three-dimensional shape based on data representing a three-dimensional shape, a fillet surface is used as a fillet line for line drawing output representing a fillet portion. By generating one line segment data of the ridge line to be configured, it is possible to output an image by a simple line drawing that can be easily recognized as a fillet.

Embodiments according to the present invention will be described below. Each embodiment described below shows an embodiment related to the image processing apparatus of the present invention. In the present application, the image processing apparatus of the present invention includes means for executing each processing step of the image processing method of the present invention as a constituent element. Therefore, the embodiments of the image processing method of the present invention are included in the embodiments related to the image processing apparatus described below.
FIG. 2 is a block diagram showing the configuration of the image processing system according to the embodiment of the present invention.
The image processing system of the present embodiment shown in FIG. 2 includes a 3D database 20 that holds data representing a three-dimensional shape, a fillet extraction unit 115 that extracts a fillet part from 3D data to be processed in the 3D database 20, and an extraction A fillet line generating unit 113 for generating a fillet line based on the 3D data of the fillet unit, and an operation unit 14 such as a keyboard and a mouse, for instructing the fillet line generating unit 113 about the fillet line generation conditions An information input unit 111 for inputting information through the operation unit 14 and a display unit 117 having a display 13 and outputting data from the 3D database 20 and fillet lines generated by the fillet line generation unit 113 on the display 13 Prepare as.
In the 3D database 20, fillet 3D data used for generating a fillet line is defined as a shape obtained by sweeping an arc (see the description of the prior art in the “Background Art” section above). On the other hand, in 3D data representing one solid model including a fillet part as a component, the state of fillet surface data differs depending on the data configuration, and the surface is used as attribute information of data of each surface constituting the solid model. It is not necessarily shown to be a fillet. Therefore, in such a case, the existence of fillet surface data is recognized by the above-described definition of the fillet.
The fillet extraction unit 115 extracts fillet data recognized by the above-described method from 3D data representing the solid model to be processed, and sends the extracted fillet information to the fillet line generation unit 113. The fillet information includes geometric information of a curved surface corresponding to the fillet surface or ridge lines constituting the fillet surface.
The fillet line generation unit 113 uses the fillet information received from the fillet extraction unit 115 and numerical information such as the type of fillet line to be generated and the coefficients used when generating the fillet line, which are given as processing conditions from the information input unit 111. , Generate a line segment representing the fillet part. A line segment representing the generated fillet portion is sent to the display portion 117. The display unit 117 receives the 3D data of the target solid model given from the 3D database 20 and the line segment given from the fillet line generation unit 113, and displays a line drawing in which the fillet portion in the target solid model is expressed by a simplified fillet line. The image is displayed on the display 13 or the like (an image output form called printing may be used).

FIG. 3 is a block diagram showing a hardware configuration of an apparatus for realizing the image processing system according to the embodiment of the present invention. The hardware configuration of the image processing apparatus shown in FIG. 3 shows an example implemented by a general-purpose information processing apparatus (computer). The CPU 11, the memory 12, a display device 13 such as a CRT display, and an input such as a mouse and a keyboard Each element of the external storage device 15 such as the device 14 and a hard disk drive or a CD-ROM drive is connected to the bus 18 to constitute the device.
In order for this image processing apparatus to function as the above-described image processing system (FIG. 2), a database (corresponding to the 3D database 20 in FIG. 2) holding 3D data representing the solid model to be processed and the solid model are represented. A program (software) is required for causing an information processing apparatus (computer) to execute a fillet line generation processing procedure according to the present invention for generating a fillet line based on 3D data. These data and programs are recorded in a recording medium or memory 12 used by the external storage device 15.
The CPU 11 drives a program for executing the fillet line generation process, whereby the fillet extraction unit 115, the fillet line generation unit 113, the information input unit 111, and the display unit 117 that constitute the above-described image processing system (FIG. 2). Realize the function.

Next, 3D data image output processing capable of drawing a fillet line executed by the above-described image processing system will be described in detail according to the flow of processing.
Referring to FIG. 4 showing a flowchart of image output processing according to the present embodiment, first, numerical information such as the type of fillet line generated by the fillet line generation unit 113 and coefficients used when generating the fillet line is input as processing conditions. (Step S101).
The input of these processing conditions is performed through operation of a keyboard, a mouse or the like in the information input unit 111. Note that a solid model managed by the 3D database 20 is designated in advance as an object of the image output process, and 3D data of the designated model is the object of this process.
One of the following (a) to (c) is designated as the type of fillet line input as a processing condition. Note that a method of performing a user input operation from the information input unit 111 may be used only when one of the following (a) to (c) is set as a default setting and the setting is to be changed.
(a) Use the boundary curve of the fillet
(b) Generate a line segment at the center of the fillet
(c) Generate a line segment with a specified normal vector (angle) on the fillet plane. At the same time, coefficients (magnification, length, etc.) for adjusting the length of the fillet line to be generated are input.
Next, the fillet extraction unit 115 extracts the fillet part from the 3D data representing the solid model to be processed (step S102).
As a method for extracting the fillet portion, if the fillet surface is added to the 3D data as attribute information of the data of each surface constituting the solid model, the surface to which the information is added is extracted.
Even when such attribute information is not added, a curved surface generated by sweeping an arc such as a cylindrical surface, a conical surface, or a torus surface is extracted as a fillet portion. However, non-fillet surfaces such as complete cylinders, cones, and toruses are not extracted.
The extracted information on the fillet part includes a collection of faces constituting the fillet part, a collection of ridge lines constituting the faces, and geometric information of the face of the fillet part.

Next, according to numerical information such as the type of fillet line specified by the information input unit 111 and the coefficient used when generating the fillet line, the fillet line generated by the fillet line generating unit 113 is extracted by the fillet extracting unit 115 in the previous stage. Then, a fillet line for expressing the fillet surface as a simple line drawing, that is, a line segment representing the fillet surface by one ridge line is generated (step S103).
As the method for generating the line segment, any one of the methods (a) to (c) specified by the user's input operation is adopted. The fillet line generation processing performed in accordance with the above (a) to (c) will be described in more detail later as each embodiment.
Further, in the fillet line generation process performed by the fillet line generation unit 113, the fillet line simplified by any of the above methods (a) to (c) (that is, represented by one of the ridge lines constituting the fillet surface). The fillet line length is changed according to a coefficient for adjusting the length of the line segment designated through the information input unit 111 (step S104). Specifically, the length of the line segment is reduced by a specified magnification, or both ends of the line segment are shortened by the specified length to obtain data used for image output.
Next, the display unit 117 receives the original data of the target solid model given from the 3D database 20 and the fillet line for image output given from the fillet line generation unit 113, and a fillet in which the fillet part in the target solid model is simplified. A line drawing represented by a line is created as data used for image output such as display on the display 13 (step S105). At this time, the ridge line included in the fillet portion of the original 3D data of the target solid model is replaced with the simplified fillet line generated by the fillet line generation unit 113. At the time of line drawing output, in addition to wire frame display, hidden line processing is performed to obtain drawing output data.
Data for image output is created and used for display output on the display 13, and the processing of this flow is terminated.

Next, the fillet line generation processing step (S103) in the above-described 3D data image output processing flow (FIG. 4) capable of drawing the fillet line will be described in more detail.
When generating a fillet line, processing conditions as shown in the above (a) to (c) are set.
Accordingly, embodiments of fillet line generation processing according to each processing condition will be sequentially described as “Embodiment 1” to “Embodiment 3”.
“Embodiment 1”: Using a boundary curve of a fillet portion In the first embodiment, use of a boundary curve of a fillet portion is set as a processing condition (the set processing condition is the step in FIG. 4). (Acquired in S101).
Referring to FIG. 5 showing the flow of the fillet line generation process (subroutine of S103 in FIG. 4) according to the embodiment in this case, first, the fillet surface is constructed from the information of the fillet portion extracted in the previous stage (fillet surface). All ridgelines surrounding the surface are acquired (step S501).
As for the ridge line surrounding the acquired fillet surface, when a solid model as shown in FIG. 12 is taken as an example, ridge lines having boundary lines L1, L2, L3, and L4 surrounding the fillet portion FL shown in the figure are obtained. The candidates for ridge lines used as fillet lines are further narrowed down from these (step S502). That is, of the acquired ridge lines, except for the arc ridge line (in the example of FIG. 12, the ridge lines L3 and L4 are excluded), when the two ridge lines share the end points, and the tangent vectors of the ridge lines at the end points match, By performing an operation of connecting those ridge lines, candidates are narrowed down to the obtained connected ridge lines. As a result, in the example of FIG. 12, the ridge lines that have the ridge lines L1 and L2 as boundary curves are narrowed down as connected ridge lines.
Next, any one of the obtained connected ridge lines is selected and used as a fillet line (step S503). For which ridge line group to select, use the center point of the ridge line group, the average of the end points of all the ridge lines, etc., and select one with the minimum (or maximum) value of (x, y, z) Any boundary curve of the fillet portion is selected as a target fillet line. When selecting a fillet line by this method, the fillet line to be used is judged based on a certain selection criterion on all fillet surfaces to be processed, and the line drawing expression of the fillet line does not vary. Like that.
FIG. 6 shows the result of applying the first embodiment to a solid model SM6 (a model having a stepped surface and having corners of irregularities formed by horizontal and vertical surfaces as fillet portions) having the same shape as FIG. A line drawing is shown.
In FIG. 6, a fillet line generated by the method of the present embodiment, in which the fillet portion is expressed by a simplified fillet line, is indicated as L6. A fillet line L6 in the figure shows a boundary curve having a minimum value as a result of the fillet line.

“Embodiment 2” —Generates a line segment at the center of the fillet portion In Embodiment 2, when the processing condition is set to generate a line segment at the center of the fillet portion (the set processing condition is (Obtained in step S101 in FIG. 4).
Referring to FIG. 7 showing a flow of fillet line generation processing (subroutine of S103 in FIG. 4) according to the embodiment in this case, first, data representing the configuration of the fillet surface from the information of the fillet portion extracted in the previous stage. Is acquired (step S701).
Since the fillet surface is defined in the data representing the configuration of the acquired fillet surface, a line segment corresponding to the center of the fillet portion is calculated from this definition, and this is generated as a fillet line (step S702).
The fillet line calculation method can be implemented by the following two methods as a form adapted to the definition of the fillet surface.
The first method is when the fillet surface is defined by sweeping an arc curve. In this case, this is due to the method of obtaining the midpoint of the arc curve at a plurality of locations on the defined fillet surface and generating the ridge line obtained by connecting the obtained midpoints as the fillet line. The second method is a case where the fillet surface is defined by a parametric curved surface. In this case, when calculating an equal parametric curve among the parameters (u, v), the parametric direction to be an arc curve is found, and the parametric curve when the parametric value is given “0.5” is calculated. This is due to the method of generating the desired fillet line. For example, if the equiparametric curve in the u direction is an arc curve, the equiparametric curve with u = 0.5 is used as the fillet line.
FIG. 8 shows the result of applying the second embodiment to a solid model SM8 (a model having a stepped surface and having corners of irregularities formed by horizontal and vertical surfaces as fillet portions) having the same shape as FIG. A line drawing is shown.
In FIG. 8, the fillet line generated by the method of the present embodiment expressing the fillet portion with a simplified single fillet line is indicated as L <b> 8. A fillet line L8 in the figure shows a result of generating a line segment connecting the centers of the arcuate curves of the fillet portion as a fillet line.

“Embodiment 3” —Generates a line segment having a specified normal vector (angle) on the fillet plane. Embodiment 3 generates a line segment having a specified direction (angle) on the fillet plane. Is set as a processing condition (the set processing condition is acquired in step S101 in FIG. 4).
Referring to FIG. 9 showing the flow of fillet line generation processing (subroutine of S103 in FIG. 4) according to the embodiment in this case, first, data representing the configuration of the fillet surface from the information of the fillet portion extracted in the previous stage. Is acquired (step S901).
Next, a normal vector that matches the specified normal vector direction (angle) acquired as the fillet line generation condition in the previous step (FIG. 4, step S101) from the data representing the fillet surface configuration acquired in the previous stage. A point on the fillet surface having the above is obtained, and a line segment passing through the obtained point on the fillet surface, that is, a line segment connecting points in which the normal vector on the fillet surface points in a predetermined direction is generated as a fillet line ( Step S902).
In this embodiment, the normal vector direction (angle) to be set can basically be arbitrarily specified, and the fillet line generation condition can be optimized according to the 3D model to be processed. It becomes possible.
FIG. 10 shows a result of applying Embodiment 3 to a solid model SM10 (a model having a stepped surface and having corners of irregularities formed by horizontal and vertical surfaces as fillet portions) having the same shape as FIG. A line drawing is shown.
In FIG. 10, a fillet line generated by the method of the present embodiment, in which the fillet portion is expressed by a simplified fillet line, is indicated as L <b> 10. The fillet line L10 in the figure shows the result of generating a line segment connecting points on the fillet plane having a normal vector direction (angle) that can be arbitrarily specified as a fillet line.

By the way, in the flow of 3D data image output processing (FIG. 4) capable of drawing the fillet line, the length of the line segment designated through the information input unit 111 after the fillet line is generated (step S103). The length of the fillet line is changed in accordance with a coefficient for adjusting (Step S104). Specifically, the length of the line segment is reduced by a specified magnification, or both ends of the line segment are shortened by the specified length to obtain data used for image output.
FIG. 11 shows a line drawing obtained by applying the process of shortening both ends of the line segment representing the fillet line to the fillet line according to the second embodiment. In the example shown in the figure, the solid model SM11 having the same shape as the above example is generated with the fillet line shown in the second embodiment, that is, the line segment connecting the center of the arcuate curve of the fillet portion (see FIG. 8). ), When the line segment is generated, a processing condition for shortening both ends of the fillet line is given. Therefore, as shown in FIG. 11, both ends of the obtained fillet line L11 do not reach the ridge line on the side surface, and are drawn as one cut line segment. In the case of hand-drawn illustrations, the fillet line is often drawn a little away from the other ridgelines, which reproduces the effect.

An example of a solid model SM having a fillet portion is shown. 1 is a block diagram illustrating a configuration of an image processing system according to an embodiment of the present invention. It is a block diagram which shows the hardware constitutions of the apparatus which implement | achieves the image processing system shown in FIG. 3 is a flowchart of image output processing by the image processing system shown in FIG. 5 shows a flowchart of fillet line generation processing (Embodiment 1). The line drawing obtained by applying Embodiment 1 to a solid model having the same shape as in FIG. 12 is shown. 7 shows a flowchart of fillet line generation processing (second embodiment). A line drawing obtained by applying the second embodiment to a solid model having the same shape as in FIG. 12 is shown. 9 shows a flowchart of fillet line generation processing (third embodiment). A line drawing obtained by applying the third embodiment to a solid model having the same shape as in FIG. 12 is shown. The line drawing obtained by applying the process of shortening both ends of the line segment representing the fillet line to the fillet line of the second embodiment is shown. The prior art example of the illustration figure of the solid model with a fillet part is shown. The prior art example (FIG. 12 is further simplified) of the illustration figure of the solid model with a fillet part is shown.

Explanation of symbols

11 .... CPU, 12 .... memory,
13 .... Display device (display), 14 .... Input device,
15..External storage device, 20..3D database,
111 .. Information input part, 113 .. Fillet generation part,
115 .. Fillet extraction unit, 117 .. Display unit,
SM · Solid model, FL · · Fillet part,
L6, L8, L10, L11 ·· Fillet lines.

Claims (8)

  An image processing apparatus capable of generating line drawing output data having a three-dimensional shape based on data representing the three-dimensional shape, and a fillet portion extracting means for extracting fillet portion data from the data representing the three-dimensional shape to be processed And a fillet line generating means for generating one line segment data of a ridge line constituting the fillet surface as a fillet line for line drawing output expressing the fillet part based on the extracted fillet data An image processing apparatus.   2. The image processing apparatus according to claim 1, wherein the fillet line generating unit is a unit that uses the generated line segment as a boundary curve of a data fillet surface.   The image processing apparatus according to claim 1, wherein the fillet line generating unit is a unit that uses the one line segment to be generated as a curve passing through a center of a fillet surface.   2. The image processing apparatus according to claim 1, wherein the fillet line generating unit sets the one line segment to be generated as a line segment passing through a point where a normal vector on a fillet plane faces a predetermined direction; An image processing apparatus characterized by that.   The image processing apparatus according to claim 1, further comprising a processing condition input unit that inputs a processing condition when generating line drawing output data of a fillet unit. The fillet line generating unit includes the one line segment to be generated. Can be any one of the boundary line of the data fillet surface, the curve passing through the center of the fillet surface, and the line segment passing through the point where the normal vector on the fillet surface forms the specified direction, and the processing condition input means An image processing apparatus characterized in that it is a means for executing one line segment generation process designated by.   6. The image processing apparatus according to claim 1, further comprising a processing condition input unit configured to input a processing condition when generating line drawing output data of a fillet unit. 6. An image processing apparatus characterized in that a length of one line segment is changed according to a coefficient designated by the processing condition input means.   A program for causing a computer to function as a fillet part extracting unit and a fillet line generating unit provided in the image processing apparatus according to claim 1.   An image processing method capable of generating line drawing output data having a three-dimensional shape based on data representing the three-dimensional shape, and a step of extracting fillet data from the data representing the three-dimensional shape to be processed, and extraction An image processing method comprising: generating one line segment data of a ridge line constituting a fillet surface as a fillet line for line drawing output expressing the fillet part based on the data of the fillet part .

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