JPH0816635A - Automatically generating device/method for auxiliary line segment in two-dimensional drawing and cad/cam system provided with automatically generating function for auxiliary line segment in two-dimensional drawing - Google Patents

Abstract

PURPOSE:To automatically generate the auxiliary line segments for a two-dimensional drawing of a trihedral view. CONSTITUTION:The areas R1 and R2 are decided for generation of the auxiliary line segments based on the linear line segment op of a side view (y-z plane) corresponding to a point s2 set on a circle (arc) jk of a plan (z-x plane) and the linear line segments eg and fc which are parallel to an (x) axis on a front view (x-y plan). The end points w1 and w2 are set at the points having the same (x) coordinates as the point s2 on both line segments eg and fc which are circumscribed to the area R1. Then an auxiliary line segment w1w2 is generated between both points w1 and w2. Meanwhile the end points w3 and w4 are set at the points having the same (z) coordinates as a point (j) or (k) on the linear line segments ov and pr which are circumscribed to the area R2. Thus an auxiliary line segment w3w4 is generated between both points w3 and w4 respectively.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an apparatus and method for generating an auxiliary line segment in a two-dimensional drawing, and a CAD / CA having a function of automatically generating an auxiliary line segment in a two-dimensional drawing.
Regarding the M system.

Two-dimensional drawings include a front view (xy plan view), a plan view (zx plan view) and a right side view (yz).
Plan view) (these three views are hereinafter referred to as "three views"), left side view (yz plan view), bottom view (zx plan view) and rear view (xy plan view). Of the drawings are included.

The auxiliary line segment is a tangent line representing a portion where surfaces are smoothly connected to each other (first differential continuation, hereinafter referred to as "sliding contact"), and a rotating body (cylinder, cone, ring, sphere, etc.). There is a silhouette line segment that represents the silhouette that occurs when is projected onto a three-view drawing.

CAD / CAM systems include CAD (Co
mputer Aided Design) system and CAM (Comput
er Aided Manufacturing) system with only one of them, and a system with both.

[0005]

BACKGROUND ART When designing a product or the like by a CAD / CAM system or the like, a design object is generally represented by three views of a front view, a plan view and a side view, and two-dimensional drawing data of the three views is CAD. Created by the system. Then, the three-dimensional model is restored based on the two-dimensional drawing data.

As a method of restoring a three-dimensional model from two-dimensional drawing data, there is a method described in Japanese Patent Laid-Open No. 6-52264. In these restoration methods, the vertices of a solid are first generated from the corresponding points in the three views. Then, a ridgeline connecting the vertices is generated. Further, a candidate surface is generated in the area surrounded by the ridge, and it is determined whether the candidate surface is true or false. A three-dimensional model is generated by combining the surfaces determined to be true.

In order to restore an accurate three-dimensional model,
In addition to the line segments that make up the contours of the solid and the line segments that correspond to the ridges of the solid that connect the faces, auxiliary line segments (tangents and silhouette line segments) must be input. If the auxiliary line segment is not input, the three-dimensional model cannot be restored from the three-dimensional drawing, or even if it can be restored, the restored three-dimensional model is often not accurate. Auxiliary line segments also make it easier to understand a two-dimensional drawing (three-dimensional drawing) created based on a three-dimensional model, or to represent a curved surface that cannot be represented by conventional drawing methods (using solid lines and broken lines). It is also useful.

Therefore, the user (the person who inputs the three views)
Needs to accurately determine the part where the faces are in sliding contact with each other and the part of the silhouette of the curved face when inputting the three-view drawing, and to input the auxiliary line segment, which considerably burdens the user. .

[0009]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide an apparatus and method for automatically generating auxiliary line segments in a two-dimensional drawing for a three-view drawing.

An automatic line segment automatic generation device for a two-dimensional drawing according to the present invention is a drawing data storage means for storing two-dimensional drawing data for three planes drawn by the orthogonal projection method.
Knowledge storage means for storing knowledge for recognizing a three-dimensional model restored based on the two-dimensional drawing data, knowledge stored in the knowledge storage means for the two-dimensional drawing data stored in the drawing data storage means By recognizing the three-dimensional model reconstructed based on the two-dimensional drawing data, the two-dimensional region in which the auxiliary line segment is to be generated based on the three-dimensional model recognized by the recognizing means. Auxiliary line segment area determining means defined in the drawings, endpoint determining means for determining at least two endpoints of the auxiliary line segment to be generated in the area determined by the auxiliary line segment area determining means, and the endpoint determining means. The auxiliary line segment generating means for generating the auxiliary line segment connecting the end points is provided.

In the method for automatically generating auxiliary line segments in a two-dimensional drawing according to the present invention, two-dimensional drawing data for three planes drawn by the orthographic projection method is stored in advance in a drawing data storage device, The knowledge for recognizing the three-dimensional model restored based on the data is stored in advance in the knowledge storage device, and the knowledge stored in the knowledge storage device is stored in the two-dimensional drawing data stored in the drawing data storage device. By recognizing the three-dimensional model to be restored based on the two-dimensional drawing data, based on the recognized three-dimensional model, the area in which the auxiliary line segment is to be generated is defined in the two-dimensional drawing, and At least two end points of the auxiliary line segment to be generated are determined in the determined area, and the auxiliary line segment connecting the determined end points is generated.

The two-dimensional drawing data includes points, line segments (straight line segments, curved line segments (circles, ellipses, and arcs that are a part of these)), regions surrounded by line segments, and the like.

The drawing data storage means (storage device) and the knowledge storage means (storage device) include a magnetic disk storage device,
Various storage devices such as an optical disk storage device and a semiconductor memory are included. Further, these storage devices may be those provided inside the auxiliary line segment automatic generation device or those connected to the outside.

The recognized three-dimensional models include cylinders, cones, spheres, toruses and oblique cylinders. Cylinders include those whose base is a circle and those which are fan-shaped (including a semicircle). Cones include right circular cones, truncated cones, and those of which the bases are fan-shaped (including semi-circles). In the torus, a circle was swung 360 degrees around the axis of rotation, a circle swung at an angle less than 360 degrees, and a fan shape (including a semicircle) was swung 360 degrees around the axis of rotation. Included are those rotated at an angle of less than 360 degrees. The sphere includes a crown, a hemisphere,
A part of a sphere such as a sphere is included. An oblique cylinder is not an oblique cylinder but a cylinder that is drawn to be inclined with respect to at least one coordinate axis in the three-view drawing. Oblique cylinders include those whose bottom is a circle and which are fan-shaped (including a semicircle).

The auxiliary line segment includes the tangent line segment and the silhouette line segment as described above. These tangents and silhouette lines include straight lines and curved lines (circles, ellipses, and arcs that are a part of these). For example, Figure 12
In the three-sided view of the truncated cone shown in (A), an auxiliary line segment (silhouette line segment) is required for the silhouette on the side of the truncated cone. This silhouette line segment is the line segment s1s5, s2s6, s3s7, s4 represented by the one-dot chain line in FIG. 12 (B).
s8 (plan view), w5w6 (front view) and w7w8 (side view). In addition, FIG. 17 shows a spherical cap (a solid body represented by an arc bs1c in the plan view) and a truncated cone (a solid body represented by a trapezoid bchg in the plan view) that is in sliding contact therewith. In this solid, an auxiliary line segment (tangent line) is required at the part where the spherical crown and the truncated cone are in sliding contact. This tangential line segment is a straight line segment bc (plan view) represented by a one-dot chain line, and a point v.
A circle (front view) passing through 6, v7, v5, and v8, and a straight line de (side view).

According to the present invention, the three-dimensional model restored from the two-dimensional drawing is recognized, and the area in which the auxiliary line segment is to be generated is determined based on the recognized three-dimensional model.
Then, in this area, the end points for which the auxiliary line segment should be generated are determined, and the auxiliary line segment is generated.

According to the present invention, since the auxiliary line segment is automatically generated, it is not necessary for the user to input the auxiliary line segment, and the input man-hour and burden of the user can be reduced. In addition, an accurate 3D model can be restored even if an auxiliary line segment has not been input.

Preferably, auxiliary knowledge for determining whether or not an auxiliary line segment should be generated between the above-mentioned defined auxiliary line segment end points is stored in advance in the auxiliary knowledge storage device, and the auxiliary knowledge is stored in the auxiliary knowledge storage device. Based on this, it is determined whether or not the auxiliary line segment should be generated. When it is determined in the above determination that the auxiliary line segment should be generated, the generation of the auxiliary line segment is performed. By using this auxiliary knowledge, the place where the auxiliary line segment should be generated can be more accurately determined.

For each design field (ship design field, computer system housing design field, relay switch design field, etc.), the characteristics of the two-dimensional drawing (number of line segments, line segment length) are generally used. , The size of the design target, etc.) are different, and the location where the auxiliary line segment should be generated is also often different. Therefore,
It is preferable to provide a plurality of types of auxiliary knowledge (for example, one type for each design field). Then, the feature of the two-dimensional drawing data is extracted, and based on the extracted feature of the two-dimensional drawing data, an appropriate one kind of auxiliary knowledge is selected from the plurality of kinds of auxiliary knowledge stored in the auxiliary knowledge storage device. It is preferably selected.

Thus, for example, the location where the auxiliary line segment should be generated can be accurately determined based on the auxiliary knowledge suitable for each design field.

Further, this auxiliary knowledge is updated on the basis of an externally given command to erase unnecessary auxiliary line segments from the generated auxiliary line segments or a command to generate a missing auxiliary line segment. ， Preferable to be learned.

The command to delete and generate this auxiliary line segment may be given by the user.

Even if the auxiliary knowledge is used, an unnecessary auxiliary line segment may be generated or a necessary auxiliary line segment may not be generated. In such a case, correction (erasing unnecessary auxiliary line segments, addition (generation) of necessary auxiliary line segments) is performed by the user. The auxiliary knowledge is updated (learned) based on the correction result of this user. For example, the line segment connected to the added auxiliary line segment is a straight line or a circle, or the number of line segments connected to the deleted auxiliary line segment is used. Knowledge is updated.

As a result, the situation in which the endpoint determined by the endpoint determining means is determined (whether the line segment where the endpoint exists is a straight line or a circle, the number of line segments connected to the endpoint, etc.) By using auxiliary knowledge, it becomes possible to more accurately determine whether to generate an auxiliary line segment at a given time.

On the basis of the above-mentioned externally given auxiliary line segment erasing command of the generated auxiliary line segments or the lacking auxiliary line segment generation command, the auxiliary line is included in the two-dimensional drawing data. Minutes can also be erased or generated.

In one embodiment of the present invention, the automatic line segment automatic generation apparatus for a two-dimensional drawing according to the present invention is constituted by a computer system, and the automatic line segment automatic generation method for a two-dimensional drawing is a computer system.
Performed by the system.

A CAD / CAM system having an automatic generation function of an auxiliary line segment in a two-dimensional drawing according to the present invention is
Drawing data storage means for storing two-dimensional drawing data for three planes drawn by the orthogonal projection method, knowledge storage means for storing knowledge for recognizing a three-dimensional model restored based on the two-dimensional drawing data, Recognition means for recognizing a three-dimensional model restored based on the two-dimensional drawing data by applying the knowledge stored in the knowledge storage means to the two-dimensional drawing data stored in the drawing data storage means,
Based on the three-dimensional model recognized by the recognition means, an auxiliary line segment area determining means for defining an area in which an auxiliary line segment is to be generated in a two-dimensional drawing is generated in the area determined by the auxiliary line segment area determining means. It is provided with end point determining means for determining at least two end points of the auxiliary line segment to be formed, and auxiliary line segment generating means for generating an auxiliary line segment connecting the end points determined by the end point determining means.

As a result, even in the CAD / CAM system, the auxiliary line segment is automatically generated, so that the data input man-hour of the user (input person) can be reduced,
In addition, an accurate 3D model can be restored.

The automatic line segment automatic generation apparatus and method according to the present invention can be generally defined as follows.

That is, the apparatus according to the present invention for automatically generating an auxiliary line segment on a two-dimensional drawing (data) representing a three-dimensional model for improving the comprehension degree of the two-dimensional drawing is a three-dimensional model. Based on the means for detecting the region where the auxiliary line segment appears on the two-dimensional drawing (data), and the position where the auxiliary line segment is provided in the region on the two-dimensional drawing (data) detected by the detecting means. And means for generating (a data representing) the determined auxiliary line segment.

Two-dimensional drawing (data) representing a three-dimensional model
In addition, the method according to the present invention for automatically generating an auxiliary line segment for improving the comprehension of a two-dimensional drawing is based on a three-dimensional model. Data), determine the position where the auxiliary line segment is provided in the detected area on the two-dimensional drawing (data), and determine (the data representing the auxiliary line segment)
Is generated.

The auxiliary line segment includes a tangent line segment and a silhouette line segment.

According to the present invention, the auxiliary line segment is automatically generated on the two-dimensional drawing data.
It is not necessary for the D / CAM operator to add an auxiliary line segment, and an appropriate auxiliary line segment can be drawn. The auxiliary line segment is used not only when the 3D model is restored from the 3D view, but as described above, in order to make it easier to understand the 2D drawing created based on the 3D model.
Also, it is useful for representing a curved surface that is difficult to represent by ordinary drawing methods.

[0034]

[Explanation of the embodiment]

1. First Embodiment 1.1 System Configuration FIG. 1 is a block diagram showing the configuration of the three-dimensional model restoration device in the first embodiment.

The computer system 1 is a CAD / C
It may be an AM system. The display device 4 displays a three-dimensional view and a three-dimensional model restored from the three-view, and is composed of a CRT display device, a liquid crystal display device, a plasma display device, or the like. The input device 5 is for inputting two-dimensional drawing data, a command for automatically generating auxiliary line segments, and the like, and is composed of a keyboard, a mouse, an input pen, and the like.

Further, the two-dimensional drawing data storage device 2 and the basic knowledge storage device 3 can be realized by one storage device.

The two-dimensional drawing data storage device (magnetic disk storage device, optical disk storage device, etc.) 2 stores two-dimensional drawing data representing each of the three views. CA
The two-dimensional drawing data created by the D / CAM system may be given from the CAD / CAM system to the two-dimensional drawing data storage device 2. An example of a three-view drawing is shown in FIGS.

The two-dimensional drawing data is composed of line segment data. The line segment includes a straight line segment and a curved line segment. There are a circle (circumference) and an ellipse (elliptical circumference) in the curved line. A circle (circumference) includes an arc that is a part of the circumference. Further, the ellipse (elliptic circumference) includes an elliptic arc that is a part of the elliptic circumference. FIG. 2 shows a data structure of line segment data stored in the two-dimensional drawing data storage device 2.

The "type" indicates whether the line segment data is a straight line, a circle or an ellipse. For example, in FIG. 11 (A), straight line segments ab, bc, cd, da,
The type of line segment data such as ge, ef, hi, ik, km, and mh is a straight line, and the type of line segment data of a curved line segment jk is a circle. In FIG. 14, the type of line segment data such as the curve segment v7 (the starting point and the ending point are the same point (v7) in an ellipse) is an ellipse.

The "line type" includes a solid line, a broken line and a one-dot chain line. A solid line represents a visible line, and a broken line represents a hidden and invisible line (hidden line). The alternate long and short dash line represents auxiliary lines (tangling lines and silhouette ridgelines). For example, in FIG. 11A, the straight line segment ab, the curved line segment jk, etc. are solid lines, and the straight line segment v
q is a broken line.

"Start point" represents a pointer to data representing the start point coordinates, and "end point" represents a pointer to data representing the end point coordinates. The start point coordinates and end point coordinates are x coordinates and y coordinates in front view two-dimensional drawing data, z coordinates and x coordinates in plan view two-dimensional drawing data, and y coordinates and z coordinates in side view two-dimensional drawing data. Respectively represented by. For example, in FIG. 11A, the starting point coordinates of the straight line segment ab are the coordinates (x coordinate and y coordinate) of the point a, and the ending point coordinates are the coordinates of the point b (x coordinate and y coordinate). The starting point coordinates of the curved line segment jk are the coordinates of the point j (z coordinates and x coordinates), and the ending point coordinates are the coordinates of the point k (z coordinates and x coordinates). In FIG. 12 (A), since the curve segment e (e1e2) is a circle, the starting point coordinates and the ending point coordinates are the same point e.

Hereinafter, each of the "start point" and the "end point" may be referred to as an end point. Further, the “start point” and the “end point” may be collectively referred to as both end points.

The "center point" represents a pointer to data representing the center coordinates of a circle or an ellipse when the line segment data type is a circle or an ellipse. The coordinates of the center point are also x in the two-dimensional drawing data of the front view, like the coordinates of the start point and the end point.
The coordinates and y coordinates are z in the two-dimensional drawing data of the plan view.
The coordinate and x coordinate are y in the two-dimensional drawing data of the side view.
Represents coordinates and z-coordinates, respectively. For example, Figure 11 (A)
In, the coordinates of the center point of the curve segment (arc) jk are the coordinates (z coordinate and x coordinate) of the point n. In FIG. 12 (A), the coordinates of the center points of the curved lines (circles) e (e1e2) and f (f1f2) are the coordinates of the point i (x and z coordinates). When the type of line segment data is a straight line, there is no center point, so this "center point" (pointer) is NULL indicating that there is no data indicating coordinates.

In the case of a circle, the "first radius" represents the radius of the circle. For example, in FIG. 11 (A), the curve segment (arc) jk
The first radius of is the distance between points n and k. In the case of an ellipse, the "first radius" is 1/2 the length of the principal axis in the x direction (major axis or minor axis) in the front view and plan view, and 1 in the z direction in the side view. Each of the lengths is / 2.

The "second radius" is defined only in the case of an ellipse, and is 1/2 the length of the main axis (major axis or minor axis) in the y direction in the front view and the side view, and z in the plan view. Each half of the main axis of the direction is shown.

When the curve segment is a circle, the value of the second radius is 0.
Becomes In the case of a straight line segment, the values of the first radius and the second radius are both 0.

The "start angle" and "end angle" are defined only for the curved line segment (circle and ellipse). These angles are
When a clock is associated with each of the three views, the counterclockwise angle is expressed as a positive angle and the clockwise angle is expressed as a negative angle based on the position at 3 o'clock. "Start angle" is the angle that the start point makes with the 3 o'clock direction, and "end angle" is the end point is 3
It is the angle with the direction of time. For example, in FIG. 11 (A), the starting angle of the curve segment jk is 180 degrees and the ending angle is 360 degrees. In FIG. 12 (A), the starting angles of circles e and f are 0 degrees and the ending angles are 360 degrees. In FIG. 13 (A), the dashed circle ab (start point a, end point b) has a starting angle of 90 degrees and an ending angle of -90 degrees.

The "singular point" is 12 in a circle or an ellipse.
The points on the circumference at the hours, 9 o'clock, 6 o'clock, and 3 o'clock. For example, the points s1 to s3 in FIG.
Points s1 to s4 at 12 (A) are singular points. In the areas of “singular point 1” to “singular point 4”, pointers to data representing coordinates of each unique point at 9 o'clock, 6 o'clock, and 3 o'clock counterclockwise are stored sequentially from 12:00. If the type of line segment data is a straight line, there are no singular points, so
NULL is stored in the area of 4. Also, in an arc that is a part of a circle or an elliptic arc that is a part of an ellipse, there are cases where some of the singularities 1 to 4 do not exist, so in this case, in the region corresponding to the singularity that does not exist, NULL is stored.

The straight line or curved line represented by such a data structure may be referred to as a "primitive" below.

There are a plurality of primitives in each of the three views. These plural primitives are stored as list-structured data as shown in FIG.
By accessing list L1, computer system 1 can access data representing all the primitives contained in the front, top and side views, respectively.

The basic knowledge storage device (magnetic disk storage device, optical disk storage device, etc.) 3 is used to recognize whether the figure shown in the three-view drawing is a cylinder, a cone, a ring, a sphere, or an oblique cylinder. The knowledge necessary for is stored.

In addition to the bottom of the cylinder being a circle,
Those whose bottom surface is fan-shaped (including a semicircle) are included. Cones include right circular cones and truncated cones, as well as those whose bases are fan-shaped (including semicircles). For example, x ² + (y−b) ² = a ²
(Circle equation) 360 degree swivel around the x-axis, swivel at less than 360 degree, and those circles cut in half in yz plane, etc. Be done. The sphere includes a part of a sphere such as a hemisphere and a crown. An oblique cylinder is not an oblique cylinder, but the one in which the generatrix of a right circular cylinder is not parallel to the coordinate axes but is inclined as shown in Fig. 18 (A). The diagonal cylinder includes the one whose bottom surface is fan-shaped (including a semicircle).

The basic knowledge stored in the basic knowledge storage device 3 is as follows.

In the following explanation of the basic knowledge, the "focused circle" means a circle or an arc which is a part of the circumference of a circle or an arc which is a processing target in the three views. The “focus ellipse” refers to an ellipse or an elliptic arc that is a processing target among the ellipses or the elliptical arc that is part of the circumference of the ellipse in the three-view drawing.

The "singular point of interest" is a singular point to be processed among the singular points of the circle of interest or the ellipse of interest.

The "common axis" is a coordinate axis that both two views have. The common axis between the plan view and the front view is the x axis, the common axis between the plan view and the side view is the z axis, and the common axis between the front view and the side view is the y axis.

"Non-common axis" means a coordinate axis which one of the two views has but the other does not. There are two non-common axes in the two views. The non-common axes of the plan view and the front view are the z-axis and the y-axis, and the non-common axes of the plan view and the side view are the x-axis.
The axes are the y-axis and the non-common axes in the front view and the side view are the x-axis and the z-axis.

The "left end point of the circle" means a point at the 9 o'clock position on the circumference of the circle, and the closest point to the 9 o'clock position when there is no point at the 9 o'clock position. Is the end point on the circumference of the circle. The same applies to the "left end point of the ellipse". For example, the left end point of the circle (arc) jk in FIG. 11 (A) is the point j (s1). The left end point of the circle ef in FIG. 14 becomes the point s1.

The "right end point of the circle" means a point at the 3 o'clock position on the circumference of the circle, and if there is no point at the 3 o'clock position, the position closest to the 3 o'clock position. Is the end point on the circumference of the circle. The same applies to the "right end of the ellipse". For example, the left end point of the circle (arc) jk in FIG. 11 (A) is the point k (s3).

The "upper end point of the circle" means a point at the 12:00 position on the circumference of the circle, and the point closest to the 12:00 position when there is no point at the 12:00 position. Is the end point on the circumference of the circle. The same applies to the "top point of the ellipse". For example, the upper end points of the circle (arc) jk in FIG. 11 (A) are points j and k. The upper end point of the circle e in FIG. 12 (A) is the point h. The upper end point of the circle ef in FIG. 14 is the point f.

The "lower end point of the circle" means the point at the 6 o'clock position on the circumference of the circle, and the point closest to the 6 o'clock position when there is no point at the 6 o'clock position. Is the end point on the circumference of the circle. The same applies to the "lower end of the ellipse". For example, the lower end point of the curve (arc) jk in FIG. 11 (A) is the point s2.

The "corresponding point" of an arbitrary point (designated as point A) is a plan view (designated as second plan view) different from the plan view (designated as first plan view) where point A exists. A point that exists and whose coordinates on the common axis of the first and second views have the same value as the coordinates of the point A on the common axis. For example, the figure
In 11 (A), the coordinates of the singular point s2 of interest are (z0, x0)
(Plan view) and the coordinates of point o are (y0, z0) (side view)
And In this case, since the coordinate component (z coordinate component) of the common axis (z axis) of the plan view and the side view of the focused singular point s2 and the point o are both equal to z0, the point o is the focused singular point s2.
It becomes the corresponding point of.

When the point A is a singular point, the corresponding point of the point A is sometimes called a "corresponding singular point".

The "corresponding circle" of an arbitrary point A is a circle in which the corresponding point of the point A exists on the circumference thereof. The same applies to the "corresponding ellipse" of an arbitrary point A.

An "intersection" between an arbitrary point A (z1, x1) (plan view) and its corresponding point (point B, coordinates (y1, z1)) (side view) means that points A and B are A point existing in a view different from the existing view (front view), and its coordinates are the x-coordinates of the point A (coordinates of the common axis between the view in which the point A exists and the view in which the intersection exists) x1 and the y coordinate of point B (coordinates of the common axis between the view in which point B exists and the view in which the intersection exists) y
A point (x1, y1) with 1 as the coordinate. For example, Figure 11
In (A), the intersection of points k and u is point d, and the intersection of points i and q is point b.

In the following, the singular point of interest S (the coordinates are (z0, x
(0)) is in the plan view, and the singular point of interest is the circle of interest or the ellipse of interest at 12:00 or 6:00. The knowledge when the singular point of interest is at 3 o'clock or 9 o'clock is as follows: the side view in the following knowledge is the front view, the front view is the side view, the left end point is the lower end point (or upper end point),
Since the right end point is obtained by replacing the right end point with the upper end point (or the lower end point), the description thereof is omitted here.

Knowledge when the singular point of interest is in the front view can be obtained by replacing the plan view in the following knowledge with the front view and the front view with the plan view. Knowledge when the singular point of interest is in the side view can be obtained by replacing the plan view with the side view, the front view with the plan view, and the side view with the front view. Therefore, the description of the knowledge in these cases will be omitted.

[Knowledge about Cylinder] “When the following cylinder conditions 1 and 2 are satisfied, the three-dimensional model restored from the three-view drawing including the target circle is a cylinder.”

<Cylindrical Condition 1 (Condition in Side View)> The cylindrical condition 1 is a condition to be satisfied in the line segment existing in the side view, and AND logic of the following conditions (1-1) and (1-2) Is.

(1-1) In the side view, there is a straight line segment parallel to the y-axis (the non-common axis of the side views among the non-common axes of the plan view and the side view).

(1-2) The starting point (coordinates (y1, z1)) and the ending point (coordinates (y2, z) of this straight line segment parallel to the y-axis
1); y1 <y2) is the singular point of interest S (z0, x0)
Is the corresponding point. That is, z0 = z1.

A straight line segment that satisfies the cylinder condition 1 is called a "first auxiliary line segment" of the cylinder.

<Cylinder Condition 2 (Condition in Front View)> The cylinder condition 2 is a condition that should be satisfied in the line segment existing in the front view, and the AND logic of the following conditions (2-1) to (2-5) Is.

(2-1) In the front view, straight line segments (start point coordinates are (x1, y3) and end point coordinates are (x2, y3)) parallel to the x-axis (common axis between the plan view and the front view). X1 <x2) exists.

(2-2) x-coordinates (coordinates of the common axis (x-axis) between the plan view and the front view) x1 of both end points of the straight line segment parallel to the x-axis
And x2 are the x coordinate x0 of the singular point S of interest and x1 ≤ x
There is a relationship of 0≤x2.

(2-3) The left end point of the target circle, or the end point (the end point different from the end point which is in sliding contact with the target circle) or the left end point of the primitive (straight line segment or curved line part) slidingly contacting the left end point of the target circle Let (z3, x3) be the coordinates of. The coordinates of the right end point of the target circle, the end point of the primitive that slides on the right end point of the target circle (the end point different from the end point that slides on the target circle), or the right end point are (z4, x4). The x coordinate components x1 and x2 of the end points of the straight line segment that satisfies the above (2-2) are
x3 .ltoreq.x1 .ltoreq.x4 and x3 .ltoreq.x2 .ltoreq.x4.

(2-4) y-coordinate components of both end points of a straight line segment satisfying the above condition (2-3) (common axis of side view and front view (y axis)
Y3 is the y coordinate component y1 and y2 of both end points of the straight line segment that satisfies the above-mentioned cylindrical condition 1, and y1 ≤ y3 ≤ y2
Have a relationship.

(2-5) There are at least two straight line segments that satisfy the above condition (2-4).

At least two straight line segments satisfying the cylinder condition 2 are referred to as "second auxiliary line segments" of the cylinder.

For example, when the circle of interest is the curve segment jk in FIG. 11 (A), this three-view drawing shows cylindrical conditions 1 and 2.
Therefore, the three-dimensional model reconstructed from the three-view drawing including the circle of interest is judged to be a cylinder.

When the singular point of interest is the point s2, the line segment for the first auxiliary line of the cylinder is the straight line op, and the line segment for the second auxiliary line of the cylinder is the straight line segments eg and fc. When the singular point of interest is the point s1 (j), the line segment for the first auxiliary line of the cylinder is the straight line segment e
In f, the line segment for the second auxiliary line of the cylinder becomes the straight line segments ov, pr and ut, respectively. When the singular point of interest is the point s3 (k), the line segment for the first auxiliary line of the cylinder is the line segment cd, and the second line of the cylinder is
The line segments for auxiliary lines are the straight line segments ov, pq (or pr) and ut, respectively.

[Basic Knowledge about Cone] “If the following cone conditions 1 and 2 are satisfied, the three-dimensional model restored from the three-view drawing including the target circle is a cone.”

<Cone Condition 1 (Condition in Side View)> Cone condition 1 is a condition that should be satisfied in the line segment existing in the side view, and AND logic of the following conditions (3-1) to (3-3) Is.

(3-1) In the side view, there exists a straight line segment (hereinafter referred to as an "oblique line segment") that is not parallel to any of the two coordinate axes (y axis and z axis) of the side view.

(3-2) One of the starting point and the ending point of this diagonal line segment is the corresponding point of the singular point S of interest.

(3-3) Of the start point and the end point of the diagonal line segment which satisfies the above condition (3-2), the end point which is not the corresponding point of the singular point S of interest is the corresponding point of the center point of the circle of interest, Alternatively, when there is a curved line segment that is concentric with the target circle, it is a singular point on the circumference of the curve and a corresponding point of the singular point at the same position (12:00 or 6:00) as the singular point S of interest. .

A straight line segment that satisfies the cone condition 1 is called a "first auxiliary line segment" of the cone.

<Conical Condition 2 (Condition in Front View)> The conical condition 2 is a condition to be satisfied in the line segment existing in the front view, and AND of the following conditions (4-1) to (4-4) It is logic.

(4-1) In the front view, straight line segments (start point coordinates are (x1, y1) and end point coordinates are (x2, y1) parallel to the x-axis (common axis between the plan view and the front view). X1 <x2) exists.

(4-2) The x-coordinates (coordinates of the common axis (x-axis) between the plan view and the front view) x1 and x2 of the straight line parallel to the x-axis and the x-coordinate component x0 of the singular point S of interest are , X1 ≤ x0
≤x2.

(4-3) The left end point of the target circle, or the end point (the end point different from the end point which is in sliding contact with the target circle) or the left end point of the primitive (straight line segment or curved line part) that slides on the left end point of the target circle Let (z3, x3) be the coordinates of. The coordinates of the right end point of the target circle, the end point of the primitive that slides on the right end point of the target circle (an end point different from the end point that slides on the target circle), or the right end point are (z4, x4). Above condition (4-2)
X-coordinates x1 and x2 of both end points of the straight line segment satisfying
x3 .ltoreq.x1 .ltoreq.x4 and x3 .ltoreq.x2 .ltoreq.x4.

(4-4) When there is a curved line segment that is concentric with the circle of interest, there are at least two straight lines that satisfy the above condition (4-3). If there is no curved line segment that is concentric with the target circle, there is one straight line segment that satisfies the above condition (4-3).

A straight line segment that satisfies the cone condition 2 is called a "second auxiliary line segment" of the cone.

For example, when the circle of interest in FIG. 12 (A) is the curve segment e (e1e2), this three-view diagram shows the conical condition 1
Since 2 and 2 are satisfied, the three-dimensional model restored from the three-view drawing including the circle of interest is determined to be a cone. The same is true when the circle of interest is the curved line segment f (f1f2).

When the singular point of interest is the point s2 or s6, the first auxiliary line segment of the cone is the straight line segment jk, and the second auxiliary line segment of the cone is the straight line segments ad and bc. When the singular point of interest is the point s4 or s8, the line segment for the first auxiliary line of the cone becomes the line segment mn, and the line segment for the second line of the cone becomes the line segments ad and bc. When the singular point of interest is the point s1 or s5, the line segment for the first auxiliary line of the cone is the straight line segment ab
Further, the second auxiliary line segment of the cone becomes straight line segments jn and km, respectively. When the singular point of interest is the point s3 or s7, the line segment for the first auxiliary line of the cone is the line segment cd, and the line segment for the second line of the cone is the line segments jn and km.

[Basic Knowledge about Torus] “A three-dimensional model restored from the three-view drawing including the circle of interest when the following torus conditions 1 and 2 are satisfied is an annulus.”

<Circular Condition 1 (Condition in Side View)> Circular condition 1 is a condition which should be satisfied in the line segment existing in the side view, and is defined by the following conditions (5-1) to (5-3). AND logic.

(5-1) A circle (arc) or an ellipse (elliptic arc) exists in the side view.

(5-2) The corresponding point of the singular point S of interest exists on the circumference of the circle (arc) or ellipse (elliptical arc) existing in this side view. That is, this circle (arc) or ellipse (elliptic arc)
Is a corresponding circle or a corresponding ellipse of the singular point S of interest.

(5-3) Circle (arc) that satisfies the above condition (5-2)
Alternatively, the z coordinate (coordinate of the common axis (z axis) of the plan view and the side view) of the center point of the ellipse (elliptic arc) does not match the z coordinate component z0 of the center point of the target circle.

A curve segment (circle or ellipse) that satisfies the circular condition 1 is called a "first auxiliary line segment" of the circular ring.

<Torus condition 2 (condition in front view)> Torus condition 2 is a condition that should be satisfied in the line segment existing in the front view, and the following conditions (6-1) to (6-3) AND logic.

(6-1) At least two circles (arcs) or ellipses (elliptical arcs) are present in the front view.

(6-2) On one circumference of at least two circles (arcs) or ellipses (elliptical arcs) existing in the front view, the corresponding point of the left end point of the focused circle exists, and the other circles (arcs) Alternatively, the corresponding point of the right end point of the target circle exists on one circumference of the ellipse (elliptic arc).

(6-3) A straight line parallel to the x-axis (common axis between the plan view and the front view) exists with the upper end points of the two circles or ellipses satisfying the above condition (6-2) as end points. In addition, there is a straight line segment parallel to the x-axis with each lower end point as the end point.

Each of at least two curve segments (circle or ellipse) satisfying the circular condition 2 is referred to as a "second auxiliary line segment" of the circular ring.

For example, when the circle of interest is the curved line segment g in FIG. 13 (A), this three-dimensional drawing satisfies the circular conditions 1 and 2, so that the three-dimensional drawing restored from the three-dimensional drawing containing this circle of interest. The model is judged to be a ring.

When the singular point of interest is the point s2, the line segment for the first auxiliary line of the annulus is a solid line segment (arc) jk, and the line segment for the second auxiliary line of the annulus is a solid line segment (arc). ) Ab and dc respectively. When the singular point of interest is the point s4, the line segment for the first auxiliary line of the circle is a solid curve segment (arc) nm, and the line segment for the second auxiliary line of the circle is a solid curve segment (arc) ab dc respectively. When the singular point of interest is the point s1, the line segment for the first auxiliary line of the annulus is a solid line segment (arc) ab, and the line segment for the second auxiliary line of the annulus is a solid line segment (arc) jk and nm respectively. When the singular point of interest is the point s3, the line segment for the first auxiliary line of the annulus is a solid line segment (arc) dc, and the line segment for the second auxiliary line of the annulus is a solid line segment (arc) jk and nm respectively.

[Knowledge about sphere] "The three-dimensional model restored from the three-view drawing including the circle of interest when the following sphere conditions 1 and 2 are satisfied is a sphere."

<Sphere Condition 1 (Condition in Side View)> The sphere condition 1 is a condition that should be satisfied in the line segment existing in the plan view, and the AND logic of the following conditions (7-1) to (7-3) Is.

(7-1) A circle (arc) or an ellipse (elliptic arc) exists in the side view.

(7-2) The corresponding point of the singular point S of interest exists on the circumference of the circle (arc) or ellipse (elliptical arc) present in this side view. That is, this circle or ellipse is the singular point S of interest.
Is a corresponding circle or a corresponding ellipse.

(7-3) Circle (arc) that satisfies the above condition (7-2)
Alternatively, the center coordinates of the ellipse (elliptic arc) become the corresponding points of the center coordinates of the target circle.

A curve segment (circle or ellipse) satisfying the sphere condition 1 is called a "first auxiliary line segment" of the sphere.

<Sphere condition 2 (condition in front view)> The sphere condition 2 is a condition that should be satisfied in the line segment existing in the front view, and the AND logic of the following conditions (8-1) to (8-3) Is.

(8-1) A circle (arc) or an ellipse (elliptic arc) is present in the front view.

(8-2) On the circumference of the circle (arc) or ellipse (ellipse arc) present in this front view, there is a corresponding point of either or both of the left end point and the right end point of the singular point S of interest. .

(8-3) Circle (arc) that satisfies the above condition (8-2)
Alternatively, the center point of the ellipse (ellipse arc) is the corresponding point of the center point of the circle of interest (ellipse).

A curve segment (circle or ellipse) satisfying the sphere condition 2 is called a "second auxiliary line segment" of the sphere.

For example, if the circle of interest is the curved line segment c in FIG.
Since 2 and 2 are satisfied, the three-dimensional model restored from the three-view drawing including this circle of interest is determined to be a sphere.

When the singular point of interest is the point s2 or s4, the line segment for the first auxiliary line of the sphere becomes the curve segment (circle) e, and the line segment for the second auxiliary line becomes the curve segment (circle) a. When the singular point of interest is the point s1 or s3 (e), the line segment for the first auxiliary line of the sphere is a curve segment (circle) a, and the line segment for the second auxiliary line is a curve segment (circle) e.
Respectively.

[Knowledge about Oblique Cylinder] “A three-dimensional model restored from a three-dimensional drawing including the ellipse of interest or the elliptic arc of interest is an oblique cylinder when the following conditions 1 and 2 of oblique cylinder are satisfied.”

<Oblique cylinder condition 1 (condition in plan view)
> Oblique cylinder condition 1 is a condition that should be satisfied in the line segment existing in the plan view, and AND of the following conditions (9-1) and (9-2)
It is logic.

(9-1) There exists an ellipse (ellipse arc) having the same first and second radii as the ellipse of interest and different center coordinates from the ellipse of interest.

(9-2) A singular point or endpoint of the ellipse of interest and a singular point or endpoint at the same position as the singular point or endpoint of the ellipse of interest in the ellipse satisfying the condition (9-1) are connected by a straight line segment. Has been done.

<Oblique Cylinder Condition 2 (Condition in Front View or Side View)> Oblique cylinder condition 2 is a condition which should be satisfied by the line segment existing in the front view or the side view.
It is an AND logic of 0-1) and (10-2).

(10-1) The first radius and the second radius are equal,
And at least two ellipses with different center coordinates (elliptical arc)
Exists.

(10-2) A singular point or endpoint of one ellipse of the ellipse (elliptic arc) of the above condition (10-1) and a singular point or endpoint at the same position of the other ellipse are straight line segments. It is connected.

For example, in FIG. 18A, the ellipse of interest is represented by a solid curve ef (passing point s1) and a broken curve ef.
This three-dimensional view satisfies the conditions 1 and 2 of the slanting cylinder regardless of whether it is (passing point s3) or the curved line segment g (g1g2) of the solid line, so the three-dimensional model restored from this three-dimensional view Is judged to be an oblique cylinder.

1.2 Processing in 3D Model Restoration Apparatus FIGS. 4 to 10 are flowcharts showing the flow of processing in the 3D model restoration apparatus in the first embodiment.

First, it is judged whether or not all the three views have been selected as the views for defining the circle of interest (the ellipse of interest) (step 101). If all of the three views have not been selected (NO in step 101), one of the views is selected (step 102). Planes are selected in the order of plan view, front view, and side view.

In the following, the processing when the singular point of interest is in the plan view will be described. When the singular point of interest is in the front view, the plan view and the front view in the following description may be replaced with the front view and the plan view, respectively. If the singular point of interest is in the side view, the plan view may be replaced with the side view, the front view with the plan view, and the side view with the front view. Therefore, the description of the processing in these cases will be omitted.

Subsequently, in the selected plan (plan view), curved lines (circle, arc, ellipse, elliptic arc) are searched (step 103). When a curved line is searched (YES in step 103), the searched curved line is set as the target circle or the target ellipse, and one of the singular points on the target circle or the target ellipse is selected as the target singular point ( Step 105). 12
The singular point of interest is selected in the order of hour, 3 o'clock, 6 o'clock, and 9 o'clock.

Next, the shape of the three-dimensional model restored from the circle of interest (ellipse) is recognized based on the basic knowledge (step 106).

As a result of the recognition, when it is judged that the three-dimensional model restored from the three-view drawing including the target circle is any one of a cylinder, a cone, an annulus, a sphere and an oblique cylinder (step
YES in any of 107 to 111), an auxiliary line segment is generated.

[Generation of Auxiliary Line Segment for Cylinder (Step
107, YES, step 113)] In the cylinder, the auxiliary line segment is generated in the view (front view or side view) in which the second auxiliary line line segment exists.

First, an area (auxiliary line area) R in which an auxiliary line segment is to be generated exists based on the first auxiliary line segment and the second auxiliary line segment, and the second auxiliary line segment exists. Determined by the plan.

For example, in FIG. 11A, if the singular point of interest is the point s2 (coordinates (z0, x0)), the second
Since the plan view in which the line segment for the auxiliary line exists is the front view, the auxiliary line region (R1 [x, y]) is defined in the front view.

The range of the auxiliary line region R1 [x, y] in the y direction is the first auxiliary line segment op (coordinates are o (y1, z1
), P (y2, z1); y1 <y2) based on the y-coordinate (coordinates of the common axis (y-axis) of the side view and the front view), y1 ≤ y ≤ y2. Also, the second auxiliary line segments eg and fc (coordinates g (x1, y1), e (x2,
y1), c (x1, y2), f (x2, y2); x1 <
Based on the x coordinate of x2) (the coordinate component of the common axis (x axis) of the plan view and the front view), the range in the x direction of the auxiliary line region R1 [x, y] is defined as x1 ≤ x ≤ x2.

That is, the auxiliary line area R1 is defined by the line segments ef and f.
The area is surrounded by c, cg and ge. In the front view of FIG. 11B, the hatched area is the auxiliary line area R1.

Next, the starting point and the ending point of the auxiliary line segment are determined. The start and end points are the tangent line segment of the region R1 (line segment e
f, fc, cg and ge), the singular point s2 of interest
X-coordinates (coordinates of the common axis (x-axis) between the plan view and the front view) x
It is a point having the same x coordinate as 0. In FIG. 11B, the starting point w1 (x0, y1) and the ending point w2 (x0, y2) are defined on the straight line segments eg and fc, respectively. That is, the intersection of the singular point of interest s2 and its corresponding point o is defined as the point w1, and the intersection of the singular point of interest s2 and its corresponding point p is defined as the point w2.

Subsequently, an auxiliary line segment having the start point w1 and the end point w2 as both end points is generated. Generated auxiliary line segment w1
w2 is shown by the alternate long and short dash line in FIG. 11 (B).

After that, the processing for the next singular point of interest is performed (step 112).

When the singular point of interest is the point s1 or s3, the view in which the second line segment for the auxiliary line exists is a side view, and therefore the auxiliary line area is defined in the side view. Then, in this area, an auxiliary line segment is generated in the same manner as the auxiliary lines w1 and w2. In the side view shown in FIG. 11B, the auxiliary line region R2 defined in the side view is shown by hatching, and the generated auxiliary line segment w3w4 is shown by a dashed line.

[Generation of an auxiliary line segment in the case of a cone (step
108: YES, Steps 114, 115)] In the case of a cone, a plan view (front view or side view) in which the second auxiliary line segment exists
Auxiliary line segments are respectively generated in the plan view (plan view) where the singular point of interest exists.

First, similarly to the case of the cylinder, the auxiliary line area is defined in the plan view in which the second line segment for the auxiliary line exists.
For example, in FIG. 12 (A), the singular point of interest is the point s2 or s6 (or s4 or s8) (coordinates (z0, x
0)), the auxiliary line area (R3 [x, y]) is defined in the front view.

The range of the auxiliary line region R3 [x, y] in the y direction is the first auxiliary line segment jk (or nm) (coordinates j (y1, z1), k (y2, z2); y1 <Y2) and y1 ≤ y ≤ y2 based on the y coordinate (coordinate of the common axis (y axis) in the side view and the front view).

The second auxiliary line segments ad and bc
(The coordinates are a (x4, y1), d (x3, y1), b (x2
, Y2), c (x1, y2); x1 <x3 <x4 <x2
Based on the x coordinate of one of the line segments (the coordinate of the common axis (x axis) in the plan view and the front view), the range of the auxiliary line region R3 [x, y] in the x direction is determined. . When there is one second line segment for an auxiliary line, the range of the auxiliary line region in the x direction is determined based on this one line segment.

When the range of the auxiliary line region in the x direction is determined based on the line segment bc, x1≤x≤x2. Figure 12
In the front view of (B), the area indicated by hatching is the auxiliary line area R3.

Next, the starting point and the ending point of the auxiliary line segment are determined. The start point and the end point are x-coordinates of the singular point s2 or s6 (or s4 or s8) of interest on the circumscribed line segment of the defined auxiliary line region R3 (coordinate components of the common axis (x-axis) of the plan view and front view). ) A point having the same x coordinate as x0. In FIG. 12 (B), the starting point w is on the straight lines ad and bc.
5 (x0, y1) and end point w6 (x0, y2) are defined respectively. That is, the singular point of interest s2 and its corresponding point k
Is defined as a point w6, and the intersection of the singular point of interest s6 and its corresponding point j is defined as a point w5.

Subsequently, the determined start point w5 and end point w
An auxiliary line segment with 6 at both ends is generated. In the front view shown in FIG. 12 (B), the auxiliary line segment w5 w6 generated in the auxiliary line region R3 is shown by a one-dot chain line.

Next, the line segment for the first auxiliary line (jk or n
m) corresponding points (s2 and s6) in the plan view of both end points
, Or s4 and s8) are defined as the end points of the auxiliary line segment in the plan view. Then, an auxiliary line segment is generated between these end points. For example, when the first auxiliary line segment is the line segment jk (when the singular point of interest is the point s2 or s6), the auxiliary line segment is generated between the corresponding points s6 and s2 of the end points j and k. Also, the line segment for the first auxiliary line is the line segment n
In the case of m (when the singular point of interest is the point s4 or s8), an auxiliary line segment is generated between the corresponding points s8 and s4 of the end points n and m. In the plan view shown in Fig. 12 (B),
The generated auxiliary line segments s2s6 and s4s8 are shown by a chain line.

Similarly, the singular point of interest is s1 or s
In the case of 5 or s3 or s7, the auxiliary line segment w7w8 is generated in the side view, and the auxiliary line segments s1s5 and s3s7 are generated in the plan view.

[Generation of Auxiliary Line Segment for Circular Ring (Step
109: YES, steps 116, 117)] In the case of a ring, the supplemental line segment is a plan view (front view or side view) in which the second supplemental line segment exists and a plan view in which the singular point of interest exists ( Plan view)
Are generated respectively.

First, similarly to the case of the cylinder and the cone, the auxiliary line area is set to the plan view in which the second auxiliary line segment exists based on the first auxiliary line segment and the second auxiliary line segment. Then, an auxiliary line segment having the corresponding points of the singular point of interest on the circumscribed line segment of the auxiliary line area as the start point and the end point is generated.

For example, in FIG. 13A, when the singular point of interest is the point s2, the auxiliary line area (R5 [x, y]) is defined in the front view.

The range in the y direction of the auxiliary line area R5 [x, y] is the first auxiliary line segment jk (solid circle) (coordinates are j
Based on the y-coordinates (coordinates of the common axis (y-axis) of the side view and the front view) of (y1, z1), k (y2, z1); y1 <y2), y1 ≤ y ≤ y2.

Also, the line segment ab for the second auxiliary line (solid circle)
And dc (circle of solid line), the left end point (s
1) The left end point of the second auxiliary line segment (bc) where the corresponding point exists (point w13 (x1, y1)), and the right end point (g) of the target circle exists second Line segment for auxiliary line (d
c) the right end point (point w14 (x2, y1); x2 <x
1) x coordinate (common axis (x axis) between the plan view and front view)
The coordinate range of the auxiliary line region R5 [x, y] in the x direction is defined as x2≤x≤x1.

In the front view shown in FIG. 13 (B), the auxiliary line region R5 thus determined is shown by hatching.

When the singular point of interest is the point s4, the line segment nm for the first auxiliary line (solid circle) and the line segment a for the second auxiliary line a
Based on b (solid circle) and dc (solid circle), an auxiliary line area is defined in the same range as the area R5.

Similarly, when the singular point of interest is the point s6, the first auxiliary line segment jk (broken line circle) and the second auxiliary line segments ab (broken line circle) and dc (broken line circle). ), If the singular point of interest is the point s8, the first supplemental line segment nm (broken line circle) and the second supplemental line segments ab (broken line circle) and dc (broken line circle) Based on this, each auxiliary line area is defined.

Subsequently, the starting point and the ending point of the auxiliary line segment are determined. The start point and the end point are x-coordinate components (coordinates of the common axis (x-axis) of the plan view and the front view) on the singular point s2 or s6 (or s4 or s8) of interest on the circumscribed line segment of the auxiliary line area R5. ) A point having the same x coordinate as x0. In the front view shown in FIG. 13 (B), straight line segments ad and b
Start point w9 (x0, y1) and end point w10 (x0, y) on c
2) are defined respectively.

Subsequently, the determined start point w9 and end point w
An auxiliary line segment with 10 at both ends is generated. In Fig. 13 (B),
The auxiliary line segment w9w10 generated in the auxiliary line region R5 is shown by a one-dot chain line.

Similarly, when the singular point of interest is the point s1 or s3 (or s5 or s7), the auxiliary line region R6 is defined in the side view, and the auxiliary line segment w11w12 is generated.

When the singular point of interest is the point s2 or s4, the corresponding point w13 in the front view of the left end point (s1) of the target circle and the corresponding point w14 in the front view of the right end point (s3) of the target circle. An auxiliary line segment having both end points is generated in the front view. When the singular point of interest is the point s1 or s3, the corresponding point w16 in the side view of the upper end point (s4) of the target circle and the corresponding point w15 in the side view of the lower end point (s7) of the target circle are used as end points. A line segment is generated in the side view. Similarly, an auxiliary line segment w17w18 is generated when the focused singular point is the point s6 or s8, and an auxiliary line segment w19w20 is generated when the focused singular point is the point s5 or s7.

Next, an auxiliary line segment is generated in the plan view (plan view) in which the singular point of interest exists.

When the singular point of interest is the point s2, it is a point on the line segment connecting the singular point of interest s2 and the center point i of the circle of interest, and the corresponding circle of the singular point of interest in the side view (solid line Of the curved line jk), an auxiliary line segment s2w21 having the corresponding points (w21) of the upper end point (j) and the lower end point (k) and the singular point s2 of interest is generated.

Similarly, when the singular point of interest is the point s6, the auxiliary line segment s6w21 is generated. The singular point of interest is point s
Similarly in the case of 4 and s8, the auxiliary line segment s4w22
And s8w22 are generated respectively. Similarly, when the singular points of interest are the points s1, s5, s3, and s7, the auxiliary line segments s1w23, w23s5, s7w24, and w24s3 are similarly added.
Are generated respectively.

Furthermore, when either or both of the upper end point j and the lower end point k in the corresponding circle jk (solid circle) of the singular point s2 of interest is the singular point (the 12 o'clock or 6 o'clock position) of the circle. (In FIG. 13 (B), both points j and k are singular points), passing through the corresponding point w21 of the points (both points j and k here) at the position of the singular point, and concentric with the circle of interest. A circle (curved line w24 of the one-dot chain line) is generated as an auxiliary line segment in the plan view (plan view) where the singular point of interest exists. The same applies when the singular points of interest are points s1, s3, s4, s5, s6, s7, and s8 (in FIG. 11 (B), a dash-dotted curve segment (circle) w24 is generated for each singular point. Be done).

[Generation of Auxiliary Line Segment when Cylinder is Sliding on Circular Ring] FIG. 14 is a three-dimensional view of a three-dimensional model in which the circular ring is cut and the slanted cylinder slides on the cut surface. .

The three-dimensional model restored from the curved lines ef and gh is a ring. The three-dimensional model restored from the straight line segments fi, ij, and jh is an oblique cylinder.

Straight auxiliary line segments v1v8, v9v11, v10v
12, v14 v15, and v13 v7 are generated as auxiliary line segments of an oblique cylinder described later. Circle (arc) auxiliary line segment v1v
2, and the auxiliary line segments s1s4, s2s5, v3v4,
v3v9, v5v6, and v5v13 are generated as auxiliary line segments of the above-mentioned ring.

In this solid, both or one of the two end points of the circle of interest (ef or gh) in the plan view does not exist at the position of the singular point (12:00, 3:00, 6:00 or 9:00). For example, one end point f of the target circle ef is not at the position of the singular point. The end point h is not at the position of the singular point also for the target circle gh.

As described above, when both or one of the end points of the circle of interest are not located at the positions of the singular points, the following auxiliary line segments are generated in addition to the auxiliary line segments generated in the above-mentioned torus. .

In the front view, three points v9, v10,
An elliptic auxiliary line segment v10 (a point v10 having the same start point and end point) passing through u2 is generated. The point v9 is obtained as an intersection of the corresponding point (v5) in the side view of the singular point of interest s2 and the end point (f) that does not exist at the position of the singular point in the circle of interest. The point v10 is obtained as an intersection of the corresponding point (v5) in the side view of the focused singular point s2 and the end point (h) not located at the singular point in the circle (gh) which is a concentric circle of the focused circle. The point u2 is an end point (v1) which is not at the position of the singular point in the generated auxiliary line segment v1 v2, and this end point (v1)
Is obtained as the intersection with the corresponding point u6 in the side view of.

Also in the side view, as in the front view, 3
An elliptical auxiliary line segment v13 (a point v13 having the same start point and end point) passing through the points v13, v14 and u6 is generated. The point v13 is
It is obtained as an intersection of the corresponding point (v3 (or v4)) in the front view of the singular point of interest s1 (or s3) and the end point (f) that does not exist at the position of the singular point in the circle of interest. The point v14 is the corresponding point (v3 (or v4)) in the front view of the singular point s1 (or s3) of interest and the end point (h) that is not located at the singular point of the circle (gh) that is a concentric circle of the circle of interest. It is required as an intersection. The point u6 is obtained as an intersection of the end point (v1) not located at the position of the singular point in the generated auxiliary line segment v1v2 and the corresponding point u2 in the front view of this end point (v1).

A cylinder (point i, in the plan view) on the cut surface of the torus (the surface represented by the auxiliary line of the generated ellipse)
Even if the three-dimensional models represented by j, f, and h) are not connected (three-dimensional model in which the annulus is just cut in the middle), the auxiliary line segment of the ellipse above is a front view and Generated in side view. In this case, since the cross section of the ring is represented by a solid line or a broken line (hidden line) in the three-view drawing, a one-dot chain line is generated by overlapping the solid line or the broken line. However, when restoring the three-dimensional model, in the part where the dashed line and the solid line or the broken line overlap,
Since the three-dimensional model is reconstructed based on the solid line or the broken line, there is no particular problem even if the dash-dotted line is generated by overlapping the solid line or the broken line.

[Generation of Auxiliary Line Segment for Sphere (Step 11
0 for YES, steps 118, 119)] In the case of a sphere, an auxiliary drawing is added to the view (front view or side view) in which the second auxiliary line segment exists and the view (plan view) in which the singular point of interest exists. Each line segment is generated.

First, the auxiliary line area is defined in a plan view in which the second auxiliary line segment exists. For example, in FIG. 15 (B), when the singular point of interest is the point s2 or s4, the auxiliary line area (denoted by R7 [x, y]) is defined in the front view.

The range in the y direction of the auxiliary line region R7 [x, y] is the first auxiliary line segment (circle) e (coordinates are e (y1,
Based on the y-coordinates (coordinates of the common axis (y-axis) between the side view and the front view) (y1 −r) and the y-coordinates (y1 + r) of the lower end point of z1) and the radius r), y1-r) ≤y
≤ (y1 + r).

The range of the auxiliary line area R7 [x, y] in the x direction is the second auxiliary line segment (circle) a (coordinates are a (x1
, Y1), with radius r), based on the x coordinate (coordinates of the common axis (x axis) of the plan view and front view) x1 of the left end point and the x coordinate (x1 + 2 · r) of the right end point, x1 ≤ x≤ (x1
+ 2 · r).

In the front view shown in FIG. 15B, the hatched area is the auxiliary line area R7.

Then, the starting point and the ending point of the auxiliary line segment are determined. The start point and the end point are x of the singular point s2 (or s4) of interest on the circumscribed line segment of the defined auxiliary line region R7.
Coordinate component (coordinates of the common axis (x axis) between the plan view and front view) x
It is a point having the same x coordinate as 0. In Figure 15 (B), point w
25 (x0, y1−r) and w26 (x0, y1 + r) are defined as the start point and end point of the auxiliary line segment, respectively. Further, on the circumscribed line segment of the auxiliary line region R7, corresponding points w28 and w27 in the front view with respect to the corresponding point (w31) of the singular point s2 of interest in the side view are determined as the end points of the auxiliary line segment.

Subsequently, an auxiliary line segment is generated between the defined end points. In FIG. 15 (B), the auxiliary line segments w25w26 and w27w28 generated in the auxiliary line region R7 are shown by the one-dot chain line.

Similarly, when the singular point of interest is the point s1 (or s3), the auxiliary line region R8 in the side view is the first auxiliary line segment (circle) a and the second auxiliary line segment ( Circle)
It is determined based on e. And this auxiliary line area R8
At, auxiliary line segments w29w30 and w31w32 are respectively generated.

Next, an auxiliary line segment is generated in the plan view (plan view) in which the singular point of interest exists.

The singular point of interest is s2 (6:00) (or s4
(12:00)), the singular point of interest s2 (or s4)
), And a point on the straight line connecting the center points of the target circles and corresponding to the singular point of interest in the side view (upper point (w29) (or lower end point (w30)) of the corresponding circle (curve segment e)) An auxiliary line segment s2d (or s4d) having both ends at corresponding points in the plan view (the center point d of the sphere in the case of FIG. 11 (B)) is generated.

The focused singular point is the point s1 (9:00) (or s3
(3 o'clock)), the singular point of interest s1 (or s3)
), And the left end point (w31) (or right end point (w32)) of the circle (curve segment e) corresponding to the singular point of interest in the side view, which is on a straight line connecting the center points of the target circles. An auxiliary line segment s1d (or s3d) having the corresponding points on the plan view (the center point d of the sphere in the case of FIG. 11B) as the end points is generated.

Both or one of the two end points of the target circle is not at the position of the singular point, and the corresponding circle of the target singular point (the corresponding circle of the side view when the target singular point is at 12:00 or 6:00) , If the singular point of interest is at the 3 o'clock or 9 o'clock position, the upper or lower end of the corresponding circle in the front view) is 12 o'clock or 6 o'clock
In the case of a singular point at the time position, an auxiliary line segment is generated that has endpoints that are not at the singular point of the target circle and the center point of the target circle as the endpoints.

Both or one of the two end points of the target circle is not at the position of the singular point, and the corresponding circle of the target singular point (the corresponding circle of the side view when the target singular point is at 12:00 or 6:00) , If the singular point of interest is at 3 o'clock or 9 o'clock, the upper and lower points of the corresponding circle in the front view) are neither singular points at 12 o'clock or 6 o'clock, An auxiliary line segment having the two end points of the target circle as the end points is generated.

[Generation of Auxiliary Line Segments when Other Solids Sliding on Sphere] FIG. 16 shows that four cylinders each having a semicircle at the bottom are slidably contacting the four side surfaces of a rectangular parallelepiped arranged obliquely. And a three-dimensional view of a three-dimensional model constructed by sliding 1/4 spheres on each of the four corners. A quarter sphere is obtained by dividing the sphere into four equal parts in a plane that passes through its center and is orthogonal to each other.

The three-dimensional model restored from each circle (arc) of the curved lines ef, gh, ij and km is a 1/4 sphere. The three-dimensional model restored from each of the generatrixes of the straight line segments fg, hi, jk, and me is a cylinder with a semicircular bottom. Auxiliary line segments u1u2, u2u3, u3u4 and u4u1
The figure in the part enclosed by is a rectangular parallelepiped.

Auxiliary line segments u1u2, u2u3, u3u4 and u
4u1 is generated as an auxiliary line segment of an oblique cylinder described later. Auxiliary line segments eu1, fu1, gu2, hu2, iu3
, Ju3, ku4 and mu4 are generated as auxiliary line segments of the sphere described above.

In such a solid, both or one of the two end points of the target circle (in FIG. 16, the end point e of the target circle ef is indicated).
And f) do not exist at the position of the singularity (condition (a)
), And a straight line segment (including an auxiliary line segment) exists between the end point not located at the position of the singular point and the center point of the sphere (the circle of interest) (condition (b)). For example, when the circle of interest is a circle (arc) ef, both end points e and f are not the positions of singular points, and an auxiliary line is provided between both end points e and f and the center point u1 of this circle of interest. There are minutes eu1 and fu1 respectively.
The same applies when the target circles are the circles gh, ij and km.

In this way, the circle of interest is the above condition (a) and
If (b) is satisfied, the following auxiliary line segments are generated in the front view and side view, respectively.

When the singular point of interest is the point s2 (6 o'clock), the corresponding point u11 of the end point e which is on the auxiliary line segment v1 v3 in the front view and which is not at the position of the singular point in the circle of interest
Is determined. Further, an intersection u10 between the center point u1 of the circle of interest and the corresponding point n in its side view, and an intersection u19 between the center point u11 and the corresponding point o in its side view are respectively defined. Then, an elliptical auxiliary line segment u10u19 (passing u11) passing through these three points is generated. Similarly,
An elliptic auxiliary line segment u10u19 (passes u12) is generated for the end point f.

Also in the case where the singular point of interest is the point s4, the auxiliary line segment u of an ellipse in the front view is similarly drawn for the end points j and i.
10u19 (through u11) and u10u19 (through u12) are generated respectively.

In the side view, when the singular point of interest is s2, the side view of the intersection point u14 between the end point e not located at the singular point position in the circle of interest and the corresponding point u11 in the front view thereof, and the center point u1 of the circle of interest. An elliptical auxiliary line segment no (passing u14) passing through three points of the corresponding point n in and the corresponding point o in the side view of the center point u1 of the target circle is generated.

In the case of the singular point of interest s4, an elliptic auxiliary line segment pq (passes u18) is similarly generated.

When the singular points of interest are s1 and s3,
Similarly to the above, in the side view, an elliptical auxiliary line segment u15u
20 (passing u16) and u15 u20 (passing u17) are generated as elliptical auxiliary line segments ab (passing u9) and cd (passing u13) in the front view, respectively.

FIG. 17 is a trihedral view of a three-dimensional model in which a truncated cone is in sliding contact with a spherical crown.

Auxiliary line segments v15 v16, v6a, v7 v10, v
5v9, v8v11 and v12v13 are generated as auxiliary line segments of the above cone. Auxiliary line segment bc, s1v15, v9v
6, v7 v8, ed and v12 v14 are generated as auxiliary line segments of the above sphere.

In such a solid, the endpoints b and c of the circle of interest bc in the plan view are not at the positions of the singular points, and a straight line segment (auxiliary line segment) is formed between the endpoints b and c and the center point of the circle of interest. Is not present).

In such a case, the length of the auxiliary line segment bc (or de) is the diameter, and the curve segment (circle) a (first
An auxiliary line segment v6 (start point v6 and end point v6) that is a concentric circle of the auxiliary line segment or the second auxiliary line segment is generated in the front view.

[Generation of Auxiliary Line in Case of Oblique Cylinder (YES in Step 111, Steps 120 and 121)] In the case of an oblique cylinder, coordinate conversion is performed so that the oblique cylinder becomes a cylinder in the three-view drawing. That is, the y coordinate is converted into the y1 coordinate, the x coordinate is converted into the x1 coordinate, and the z coordinate is converted into the z1 coordinate so that the slanted cylinder shown in FIG. 18 (A) becomes the cylinder shown in FIG. 18 (B).

Of the principal axes of the ellipse in the plan view, the length of the shorter principal axis is r1, and the length of the longer principal axis is r2. The rotation angle θ for the coordinate conversion is obtained as follows.

Θ = cos ⁻¹ (r1 / r2)

In each of the drawings, the x coordinate is converted to the x1 coordinate, the y coordinate is converted to the y1 coordinate, and the z coordinate is converted to z1.
The conversion into coordinates is performed based on the following equations.

X1 = x · cos θ y1 = y · sin θ z1 = z

As a result, the oblique cylinder is converted into a cylinder on the z1-x1 plane (plan view), the x1-y1 plane (front view) and the y1-z1 plane (side view) (FIG. 18 (B)).
Then, in this three-view drawing, the generation processing of the auxiliary line segment in the above-mentioned cylinder is performed. After that, the coordinates are restored again by the inverse transformation of the above transformation. When the coordinates are restored by the inverse transformation, auxiliary line segments are also generated between the singular points facing each other across the center point o (or p) in the plan view. That is, between singular points s1 and s5, between s3 and s7, between s4 and s8, and s2
An auxiliary line segment is generated between s6 and s6.

In this way, the auxiliary line segment is generated in the oblique cylinder. An oblique cylinder in which the auxiliary line segment is generated is shown in FIG. 19 (the auxiliary line segments s4s8 and s2s6 are not displayed because they overlap the solid line).

The above steps 105 to 121 are performed for all the singular points in each of the views to generate auxiliary line segments. When the generation process of the auxiliary line segment in each plan is completed (YES in step 101), the three-dimensional model is restored (step 122). Then, the process ends.
Since the three-dimensional model restoration process is described in detail in Japanese Patent Laid-Open No. 6-52264, the description thereof is omitted here.

2. Second Embodiment In the second embodiment, after recognizing the three-dimensional model based on the basic knowledge, whether or not to generate the auxiliary line segment at the position determined in the first embodiment is used as the auxiliary knowledge. Based on the judgment, the auxiliary line segment is generated.

2.1 System Configuration FIG. 20 is a block diagram showing the configuration of the three-dimensional model restoration device in the second embodiment. The same components as those of the three-dimensional model restoring device shown in FIG. 1 (first embodiment) are designated by the same reference numerals.

The difference from the three-dimensional model restoring device shown in FIG. 1 is that the auxiliary knowledge storage device (magnetic disk storage device,
6 is a computer system 1
Is connected to.

The auxiliary knowledge storage device 6, the two-dimensional drawing data storage device 2 and the basic knowledge storage device 3 can also be realized by a single storage device.

The auxiliary knowledge storage device 6 stores auxiliary knowledge. The auxiliary knowledge is the first one in the basic knowledge described above.
This is knowledge for determining whether or not to generate an auxiliary line segment in the auxiliary line area, which is determined based on the auxiliary line segment and the second auxiliary line segment.

When an auxiliary line segment is generated based on the first auxiliary line segment and the second auxiliary line segment in the above basic knowledge, an unnecessary auxiliary line segment is generated or a necessary auxiliary line segment is generated. It may not be done. For example, this is the case shown in FIG. 30 (A).

With respect to the singular point s2 of interest, the line segment for the first auxiliary line is the line segment im, and the line segment for the second auxiliary line is the line segments ad and b.
c, eh and fg respectively. In this case,
As shown in (B), auxiliary line regions R1, R2 and R3 are defined and auxiliary line segments w1w2, w2w3 and w3w4 are generated. However, since the side surface (cylindrical surface) of the cylinder does not exist in the region R2, the auxiliary line segment w2w3 is an unnecessary auxiliary line segment.

The auxiliary knowledge is knowledge for preventing generation of unnecessary auxiliary line segments generated based on the first auxiliary line segment and the second auxiliary line segment in the basic knowledge.

FIG. 21 shows the data structure of the auxiliary knowledge stored in the auxiliary knowledge storage device 6.

The auxiliary knowledge is composed of a plurality of types of auxiliary knowledge data and auxiliary knowledge feature data. The auxiliary knowledge data is data for determining whether or not to generate an auxiliary line segment in an auxiliary line area defined based on the first auxiliary line segment and the second auxiliary line segment in the basic knowledge. The auxiliary knowledge feature data is data used when selecting which auxiliary knowledge data to use from a plurality of auxiliary knowledge data.

All auxiliary knowledge data and auxiliary knowledge feature data are connected by pointers from the list L4 via the relay lists L5 to L7. Therefore, the computer system 1 can access all the auxiliary knowledge data and the auxiliary knowledge feature data from the list L4.

The auxiliary knowledge data and the auxiliary knowledge feature data are classified for each front view, plan view and side view. A plurality of auxiliary knowledge data and auxiliary knowledge feature data are provided for each view. The auxiliary knowledge data and the auxiliary knowledge feature data are further classified into data related to addition (generation) of auxiliary line segments and data related to deletion (deletion) of auxiliary line segments.

A plurality of pieces of auxiliary knowledge data and auxiliary knowledge feature data are provided for each plan even if the auxiliary knowledge is related to the same front view, even in each design field (for example, ship design field, computer system, etc.). The characteristics of the front view (dimensions of figures, proportion of straight lines, circles, etc. to all primitives that make up the floor plan, etc.) vary depending on the design field of the chassis, the design field of relays and switches, etc. This is to provide auxiliary knowledge suitable for each design field. As a result, it is possible to deal with the difference in the characteristics of the drawings in each design field. For example, the auxiliary knowledge data of the design field 1 is the auxiliary knowledge about the design field of a ship,
The auxiliary knowledge data of the design field 2 is the auxiliary knowledge data of the design field of the computer system.

FIG. 22 (A) shows the data structure of the auxiliary knowledge data, and FIG. 22 (B) shows an example of the auxiliary knowledge data.

[0227] The "view type" indicates whether the auxiliary knowledge data is related to the front view, the plan view or the side view. The auxiliary knowledge data shown in Fig. 22 (B) is the auxiliary knowledge data regarding the side view.

The "correction content" indicates whether this auxiliary knowledge data relates to addition (generation) of an auxiliary line segment or deletion (erasure) of an auxiliary line segment. Since the correction content of the auxiliary knowledge data shown in FIG. 22 (B) is deletion, this auxiliary knowledge data is data related to deletion.

As will be described in detail later, after the auxiliary line segment is automatically generated, the user adds (generates) an auxiliary line segment that is not sufficient for the automatically generated auxiliary line segment, or an unnecessary auxiliary line segment. May be deleted (erased). "Number of corrections" is
The number of times of addition or deletion of the auxiliary line segment performed by the user is shown. When the auxiliary line segment is deleted, the value of the number of corrections of the auxiliary knowledge data regarding deletion is incremented by 1, and when the auxiliary line segment is added, the number of corrections of the auxiliary knowledge data regarding addition The value of is increased by 1. The number of corrections (the number of deletions) of the auxiliary knowledge data shown in FIG. 22 (B) is 20 times.

In the area of "number of connected primitives", a membership function (for example, FIG. 22 (e.g., FIG. 22 (b) is used) which represents the relationship between the number of primitives connected to the modified (added or deleted) auxiliary line segment and its conformity. The pointer to the membership function shown in B) is stored.

In the "type table" area, when the generated auxiliary line segment is modified (added or deleted),
The type (straight line, circle, ellipse) of the primitive connected to (or was connected to) the modified auxiliary line and its fitness (fitness for straight line α, fitness for circle β, and ellipse) The pointer to the table showing the relationship with the matching degree of γ) is stored.

In the example shown in FIG. 22B, the goodness of fit of the straight line is 0.
5, the goodness of fit of the circle is 0.7, and the goodness of fit of the ellipse is 1.0. This is because when the automatically generated auxiliary line segment is connected to a straight line segment, α = 0.5 (50%) of the auxiliary line segment is deleted by the user (this auxiliary knowledge data is related to deletion). It means that it was done). In addition, β = 0.7 (70 of the auxiliary line segments connected to the circle)
%) Means that γ = 1 (100%) (all) of the auxiliary line segments connected to the ellipse has been deleted.

These α, β and γ are respectively calculated based on the following equations.

[Α, β and γ in deleting auxiliary line segments
Calculation formula] α = (the number of auxiliary line segments deleted among the auxiliary line segments connected to a straight line) / (the number of auxiliary line segments connected to a straight line) (1)

Β = (the number of auxiliary line segments deleted from the auxiliary line segments connected to the circle) / (the number of auxiliary line segments connected to the circle) (2)

Γ = (number of auxiliary line segments deleted from auxiliary line segments connected to ellipse) / (number of auxiliary line segments connected to ellipse) (3)

[Α, β and γ in the addition of auxiliary line segments
Calculation formula] α = (the number of added auxiliary line segments connected to a straight line) / (the number of added auxiliary line segments) (4)

Β = (the number of added auxiliary line segments connected to the circle) / (the number of added auxiliary line segments) (5)

Γ = (the number of added auxiliary line segments connected to the ellipse) / (the number of added auxiliary line segments) (6)

In the above equation, when the value of the denominator is 0, the value of the equation is 0.

When the generated auxiliary line segment is corrected (added or deleted) in the "line type table" area, it is connected to (or was connected to) the corrected auxiliary line segment.
Shows the relationship between the primitive line type (solid line, dashed line, dash-dotted line) and its fitness (fitness for solid line is δ, fitness for dashed line is ε, and fitness for dashed line is ζ) Stores a pointer to the table.

In the example shown in FIG. 22 (B), the goodness of fit of the solid line is 0.
7, the goodness of fit of the broken line is 0.8, and the goodness of fit of the chain line is 0.0. This is because when the automatically generated auxiliary line segment is connected to the solid line, δ = 0.7 (70%) of that auxiliary line segment.
Means that the user has deleted, and the auxiliary segment ε = 0.8 (80%) connected to the broken line has been deleted by the user. It means that ζ = 0 (0%) of the auxiliary line segment connected to the one-dot chain line is deleted, that is, not deleted at all, or the auxiliary line segment connected to the one-dot chain line is not generated at all.

These δ, ε and ζ are respectively calculated based on the following equations.

[Δ, ε and ζ in deleting auxiliary line segments
Calculation formula] δ = (the number of deleted auxiliary line segments among the auxiliary line segments connected to the solid line) / (the number of auxiliary line segments connected to the solid line) (7)

Ε = (the number of deleted auxiliary line segments among the auxiliary line segments connected to the broken line) / (the number of auxiliary line segments connected to the broken line) (8)

Ζ = (the number of deleted auxiliary line segments among the auxiliary line segments connected to the alternate long and short dash line) / (the number of auxiliary line segments connected to the alternate long and short dash line) (9)

[Δ, ε and ζ in the addition of the auxiliary line segment
Calculation formula] δ = (number of added auxiliary line segments connected to solid line) / (number of added auxiliary line segments) (10)

Ε = (the number of added auxiliary line segments connected to the broken line) / (the number of added auxiliary line segments) (11)

Ζ = (the number of added auxiliary line segments connected to the alternate long and short dash line) / (the number of added auxiliary line segments) (12)

In the above equation, when the value of the denominator is 0, the value of the equation is 0.

The membership function in the number of connection primitives may be a table in which the number of connection primitives and their conformity are associated with each other, or the type table and line type table may be represented by the membership function. Good.

The membership function, the type table and the line type table of the number of connection primitives in the auxiliary knowledge data quantitatively represent the characteristics of the end points of the corrected auxiliary line segment. Therefore, the number of primitives connected to the position (end point) where the auxiliary line segment is to be generated in the auxiliary line area, the type of primitive connected to the end point, and each fitness for the line type of the primitive are determined by these membership functions. It is possible to quantitatively determine whether or not an auxiliary line segment should be generated at that location by obtaining the values from the table and the table.

In the auxiliary knowledge data, in addition to or in place of the number, type and line type of connection primitives, other characteristics (the number of primitives included in the plan (a member representing the relationship between the number of primitives and their conformity) (Ship function) etc.) can also be used.

FIG. 23A shows the data structure of auxiliary knowledge feature data. FIG. 23 (B) shows an example of auxiliary knowledge feature data.

[0255] The "view type" is the same as the "view type" in the above-mentioned auxiliary knowledge data. Figure 23
The auxiliary knowledge feature data shown in (B) is the auxiliary knowledge data related to the side view because the “type of view” is the side view.

A pointer to a membership function (for example, the membership function shown in FIG. 23 (B)) representing the relationship between the number of curve segments and its fitness is stored in the “number of curve segments” area. ing. “Number of curved lines” refers to the number of curved lines (circle (arc), ellipse (ellipse arc)) included in the plan.

A pointer to a membership function (for example, the membership function shown in FIG. 23 (B)) representing the relationship between the number of primitives included in the plan and the matching degree is provided in the “primitive number” area. Is stored.
"Number of primitives" means the number of primitives included in the plan.

In the area of "minimum primitive size", a pointer to the membership function showing the relationship between the size of the minimum primitive included in the drawing and its conformity is displayed in the "maximum primitive size". Each area stores a pointer to a membership function that represents the relationship between the size of the maximum primitive included in the drawing and its suitability.

The "primitive size" in the "minimum primitive size" and the "maximum primitive size" means the length of a straight line segment, its radius if a circle (curve segment), and ellipse (curve segment). ) Then the first radius and the second
The smaller one of the radii. "Minimum size of primitive" is the smallest size of the primitives included in the plan, and "Maximum size of primitive" is the size of the primitives included in the plan. The largest one is called.

In the area of "minimum distance between primitives", a pointer to a membership function that represents the relationship between the minimum distance between primitives in a plan and its conformity is stored. "Minimum distance between primitives" means
The smallest distance between primitives. The “distance between primitives” refers to the distance between two parallel straight lines or the absolute value of the difference between the radii of two concentric circles.

The number of these curve segments, the number of primitives, etc. represent the features of the plan. Therefore, based on the auxiliary knowledge feature data, it is possible to obtain the goodness of fit for the number of curved lines included in each of the three views and the goodness of fit for the number of primitives. Then, as will be described later in detail, the auxiliary knowledge feature data having a larger average value of these matching degrees can be considered to be the auxiliary knowledge feature data more suitable for the plan.

2.2 Processing in 3D Model Restoring Apparatus FIGS. 25 to 29 are flowcharts showing the flow of processing in the 3D model restoring apparatus in the second embodiment.

First, the feature data of each of the three views (hereinafter referred to as "view feature data") is created (step 20).
1). The feature data of the floor plan are shown in Figure 24 (A).

[0264] "Type of view" is the same as that of the auxiliary knowledge feature data described above. The "number of curves", "number of primitives", "minimum primitive size", "maximum primitive size" and "minimum distance between primitives" are also as described above.

FIG. 24 (B) shows the side view feature data of the side view of the three views shown in FIG. 30 (B). The number of curves is 0, the number of primitives is 11, the minimum primitive size is 20, the maximum primitive size is 160, and the minimum distance between primitives is 20.

When the plan feature data for each plan is created, auxiliary knowledge data is selected based on the plan feature data (step 202). One of a plurality of auxiliary knowledge data regarding the front view is selected based on the view feature data of the front view. Further, one of the plurality of auxiliary knowledge data regarding the plan based on the plan characteristic data of the plan view and one of the plurality of auxiliary knowledge data regarding the side view based on the plan characteristic data of the side view, respectively. To be selected.

In selecting the auxiliary knowledge data for the front view, the front view feature data and the front view auxiliary knowledge feature data are used. The side view feature data and the side view auxiliary knowledge feature data are selected in selecting the side view auxiliary knowledge data, and the plan view plan view feature data and the plan view are selected in selecting the side view auxiliary knowledge data. The auxiliary knowledge feature data is used respectively.

For example, in selecting auxiliary knowledge data for a side view, first, all of a plurality of auxiliary knowledge feature data (FIG. 21) relating to a side view are read from the auxiliary knowledge storage device 6. Then, the "number of curves" of the drawing feature data
Is calculated based on each membership function for the “number of curve segments” of the plurality of read auxiliary knowledge feature data. For example, as shown in FIG. 24 (B), when the number of curve segments is 0, this 0 is input to the membership function of each auxiliary knowledge feature data, and the goodness of fit is obtained. An example of the calculated goodness of fit is shown in Fig. 24 (C).
Is shown in. The degree of fit of the number of curves of the auxiliary knowledge feature data 1 is 0.8, and the degree of fit of the number of curves of the auxiliary knowledge feature data 2 is 0.2.

Similarly, the conformity of “the number of primitives” and “minimum size of primitive” of the plan feature data
, “Maximum primitive size”, and “Minimum distance between primitives” are calculated based on the corresponding membership functions (FIG. 24 (C)).

Subsequently, the average value of the calculated goodness of fit is calculated for each auxiliary knowledge feature data. In Figure 24 (C),
The average value of the goodness of fit of the auxiliary knowledge feature data 1 is 0.64,
The average value of the goodness of fit of the auxiliary knowledge feature data 2 is 0.4.

Subsequently, the auxiliary knowledge feature data having the maximum average value is selected. The auxiliary knowledge feature data with the highest average fitness value is selected because the auxiliary knowledge feature data with the higher average fitness value has a feature closer to the feature of the target drawing. Because it will be done.

Then, the auxiliary knowledge data paired with the selected auxiliary knowledge feature data is selected. For example,
When the average value of the suitability of the auxiliary knowledge feature data 1 is the maximum, this auxiliary knowledge feature data 1 is selected and the auxiliary knowledge data 1 paired with this auxiliary knowledge feature data 1 (see FIG.
1) will be selected.

When there are two or more pieces of auxiliary knowledge feature data having the maximum average value, one of them is selected.

Besides selecting the auxiliary knowledge feature data based on the average value of the goodness of fit, it is also possible to use a method of selecting the auxiliary knowledge feature data having the maximum goodness of fit of the “number of curves”.

Next, the processes of steps 203 to 208 are performed. These processes are performed from step 101 in the first embodiment.
Since it is the same as the processing of 106 (FIG. 4), its explanation is omitted here.

When it is recognized that the three-dimensional model is any one of a cylinder, a cone, a ring, a sphere, and an oblique cylinder (step 209), the line segment for the first auxiliary line is formed in the same manner as in the first embodiment. An auxiliary line area is defined based on the second auxiliary line segment (step 210).

Subsequently, it is judged whether or not there are a plurality of defined auxiliary line areas (which cannot be uniquely determined) (step
211). For example, FIG. 11B in the first embodiment described above.
In the case of FIG. 12 (B) and the like, one auxiliary line area is defined, so the determination in step 211 is YES. In the front view shown in FIG. 30 (B), since three regions R1 to R3 are defined, the determination in step 211 is NO.

If NO in step 211, it is determined whether or not the auxiliary knowledge data selected in step 202 is reliable (step 212). Reliability is judged by whether the number of corrections of auxiliary knowledge data is larger than a predetermined value. If the number of corrections is greater than or equal to a predetermined value, this auxiliary knowledge data is judged to be reliable,
When the number of corrections is smaller than a predetermined value, this auxiliary knowledge data is judged to be unreliable. This is because the correction number represents the update number (learning number) of the auxiliary knowledge data as described above, and the larger this value is, the more reliable the data is.

If the auxiliary knowledge data is reliable (YES in step 212), based on this auxiliary knowledge data,
For each of the plurality of auxiliary line areas, it is determined whether or not to generate an auxiliary line segment (steps 213 to 216).

First, one of the plurality of auxiliary line areas is selected (step 213).

Subsequently, whether or not to generate an auxiliary line segment in the selected auxiliary line area is determined based on the selected auxiliary knowledge data (step 214). This determination is performed by applying the auxiliary knowledge data to the first line segment for the auxiliary line. When the first auxiliary line segment is a line segment existing in the side view, auxiliary knowledge data regarding the side view is used. If the line segment for the first auxiliary line exists in the front view, the supplementary knowledge data about the front view, and if the line segment for the first auxiliary line exists in the plan view, the supplementary knowledge about the plan view Knowledge data is used respectively.

For example, for the auxiliary line region R1 in FIG. 30B, the number of connection primitives relating to both end points i and j of the portion (line segment ij) corresponding to the region R1 in the first auxiliary line segment im, Each goodness of fit for each type and line type is obtained.

With respect to the end point i, since the number of primitives connected to the end point i is the two line segments ij and iq, the number of connected primitives is two. The goodness of fit in the numerical value 2 is obtained based on the membership function of the auxiliary knowledge data. Further, the type of the primitive connected to the end point i is a straight line, and the goodness of fit for the type is obtained based on this type and the type table. Further, the line type connected to the end point i is a solid line, and the degree of suitability for the line type is obtained based on this line type and the line type table.

The same processing as that for the end point i is performed for the end point j. Further, with respect to the auxiliary line region R2, the same processing is performed for the end points j and k.

Regions R1 (line segment ij) and R2 (line segment j
FIG. 22 (B) shows an example of the processing result for k) based on the auxiliary knowledge data.

[Processing result for region R1 (line segment ij) (each value indicates goodness of fit)] End point i: number of connected primitives = 0, type = 0.5, line type = 0.7 End point j: number of connected primitives = 0.5 , Type = 0.5, line type = 0.7

[Processing Result for Region R2 (Line Segment jk) (Each Value Shows Goodness of Fit)] End Point j: Number of Connected Primitives = 0.5, Type = 0.5, Line Type = 0.7 End Point k: Number of Connected Primitives = 0.5 , Type = 0.5, line type = 0.7

When a plurality of primitives are connected to the end points and the connected primitives are of different types, the average value of the goodness of fit of each type is obtained. For example, if a straight line and a curve are connected to the end point j, the goodness of fit value of this type is 0.5 and 0.7 with an average value of 0.
6 Even when primitives of different line types are connected to the end points, the average value of the goodness of fit is similarly obtained.

Next, the average value of all the goodnesses of fit is calculated for each auxiliary line area. For example, the above auxiliary line area R
The average value of the total goodness of fit for 1 is 0.48, and the average value of the goodness of fit for the auxiliary line region R2 is 0.57 (both are rounded to the second decimal place).

Subsequently, when this average value is equal to or greater than a predetermined value (threshold value), when the "correction content" of the auxiliary knowledge data is deletion, an auxiliary line segment is generated in the auxiliary line area. However, when the "correction content" is an addition, an auxiliary line segment is generated (steps 215 and 216).
). When this average value is smaller than the threshold value, when the “correction content” of the auxiliary knowledge data is a deletion, an auxiliary line segment is generated in the auxiliary line area, and the “correction content” is generated.
Is added, no auxiliary line segment is generated (steps 215 and 216).

If the threshold value is 0.5, the auxiliary line area R1
The average of all goodness of fit for is less than or equal to the threshold. Since the auxiliary knowledge data used (FIG. 22 (B)) relates to deletion, an auxiliary line segment is generated in this area R1. Further, since the average value of all the goodnesses of fit for the region R2 is equal to or more than the threshold value, no auxiliary line segment is generated.

By the same processing, an auxiliary line segment is generated in the auxiliary line area R3.

If there is one auxiliary line area defined based on the first auxiliary line segment and the second auxiliary line segment (if it is uniquely determined) (YES in step 211), the one auxiliary line An auxiliary line segment is generated in the area (step 219).
). In this case, auxiliary knowledge data is not used.

If the selected auxiliary knowledge data is not reliable (NO in step 212), auxiliary line segments are generated in all of the plurality of auxiliary line areas (step 219). The auxiliary line segment generation processing is as described in the first embodiment.

In this way, when the auxiliary line segment generation processing for each auxiliary line area of each plan is completed (step 203
YES in step 3), the three-dimensional model is restored (step 220).
). If the 3D model cannot be restored because the auxiliary line segment was not generated correctly, or if restoration is performed but it is not an accurate 3D model (N in step 221).
O), the user corrects (adds or deletes) the auxiliary line segment (step 222).

Next, the auxiliary knowledge data is updated (learned) based on the correction of the auxiliary line segment by the user (step 223).

The auxiliary knowledge data to be updated is the auxiliary knowledge data selected in step 202 and the auxiliary knowledge data related to addition or deletion paired with the selected auxiliary knowledge data (delete or addition). For example, in FIG. 21, when the auxiliary knowledge data 2 regarding deletion is selected in step 202, the auxiliary knowledge data 2 regarding deletion and the auxiliary knowledge data 1 regarding addition that is paired with this auxiliary knowledge data 2 are updated. Be the target.

When the user deletes the auxiliary line segment, the auxiliary knowledge data regarding the deletion is updated. When the user adds an auxiliary line segment, the auxiliary knowledge data regarding the addition is updated.

In updating, the value of the number of corrections in the auxiliary knowledge data is incremented by 1. Further, the type table in the auxiliary knowledge data is changed based on the above expressions (1) to (6), and the line type table is changed based on the above expressions (7) to (12). In addition, the membership function of the number of connected primitives in the auxiliary knowledge data is set so that the conformity of the one having the maximum value of “the number of primitives” connected to the corrected (added or deleted) auxiliary line segment becomes one. The other "primitive count" goodness of fit is changed to a normalized membership function.

When the update of the auxiliary knowledge data is completed, the process ends. Also, if the three-dimensional model is restored correctly (YES in step 221), the process ends.

When only one piece of auxiliary knowledge data is stored in the auxiliary knowledge storage device 6, the plan feature data in step 201 and the auxiliary knowledge data in step 202 are not selected. Whether or not to generate an auxiliary line segment in the auxiliary line area is determined based on this one piece of auxiliary knowledge data (step 214).

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a three-dimensional model restoring device according to a first embodiment.

FIG. 2 shows a data structure of line segment data.

FIG. 3 shows a structure of data stored in a two-dimensional drawing data storage device.

FIG. 4 is a flowchart showing a processing flow in the three-dimensional model restoration device in the first embodiment.

FIG. 5 is a flowchart showing a processing flow of the three-dimensional model restoration device in the first embodiment.

FIG. 6 is a flowchart showing a processing flow of the three-dimensional model restoration device in the first embodiment.

FIG. 7 is a flowchart showing a processing flow of the three-dimensional model restoration device in the first embodiment.

FIG. 8 is a flowchart showing a processing flow of the three-dimensional model restoration device in the first embodiment.

FIG. 9 is a flowchart showing a processing flow of the three-dimensional model restoration device in the first embodiment.

FIG. 10 is a flowchart showing a processing flow of the three-dimensional model restoration device in the first embodiment.

11A is a three-dimensional view of a solid body including a cylinder, and FIG.
Shows the trihedral view in which the auxiliary line segment is generated in the trihedral view shown in (A).

FIG. 12A is a three-sided view of a truncated cone, and FIG. 12B is a three-sided view in which an auxiliary line segment is generated in the three-sided view shown in FIG.

13A is a trihedral view of an annulus, and FIG. 13B is a trihedral view in which an auxiliary line segment is generated in the trihedral view shown in FIG.

FIG. 14 is a three-view drawing of a solid body in which a slanted cylinder is in sliding contact with a ring.

15A is a trihedral view of a sphere, and FIG. 15B is a trihedral view in which an auxiliary line segment is generated in the trihedral view shown in FIG.

FIG. 16 is a three-dimensional view of a solid body in which a rectangular parallelepiped, a sphere, and a cylinder are combined.

FIG. 17 is a three-dimensional view of a solid body combining a sphere and a cone.

FIG. 18 (A) is a three-view drawing of an oblique cylinder, and (B) is (A).
3 is a coordinate conversion of the three-view drawing shown in FIG.

FIG. 19 is a trihedral view in which an auxiliary line segment is generated in the trihedral view shown in FIG. 18 (A).

FIG. 20 is a block diagram showing a configuration of a three-dimensional model restoration device according to a second embodiment.

FIG. 21 shows a data structure of auxiliary knowledge stored in the auxiliary knowledge storage device 6.

FIG. 22 (A) shows a data structure of auxiliary knowledge data,
(B) shows an example of auxiliary knowledge data.

23A shows a data structure of auxiliary knowledge feature data, and FIG. 23B shows an example of auxiliary knowledge feature data.

[FIG. 24] (A) shows the data structure of the feature data of the floor plan, (B) shows an example of the feature data of the floor plan, (C) shows the goodness of fit of each element of the feature data of the floor plan, An example obtained based on the auxiliary knowledge feature data will be shown.

FIG. 25 is a flowchart showing the flow of processing in the three-dimensional model restoration device in the second embodiment.

FIG. 26 is a flowchart showing a processing flow of the three-dimensional model restoring device in the second embodiment.

FIG. 27 is a flowchart showing a processing flow of the three-dimensional model restoration device in the second embodiment.

FIG. 28 is a flowchart showing a processing flow of the three-dimensional model restoration device in the second embodiment.

FIG. 29 is a flowchart showing a processing flow of the three-dimensional model restoration device in the second embodiment.

FIG. 30 (A) is a three-dimensional view of a solid body including a cylinder, and (B)
Shows a trihedral view in which an auxiliary line segment is generated in the trihedral view shown in (A).

[Explanation of symbols]

 1 computer system 2 two-dimensional drawing data storage device 3 basic knowledge storage device 4 auxiliary knowledge storage device 5 input device 6 auxiliary knowledge storage device R1 to R8 auxiliary line area w1 to w32, v1 to v15 end point of auxiliary line segment

Claims (22)

[Claims] 1. A device for automatically generating auxiliary line segments for enhancing the understanding of a two-dimensional drawing on the two-dimensional drawing data representing the three-dimensional model. Means for detecting an area in which the auxiliary line segment appears on the two-dimensional drawing data, and a position for providing the auxiliary line segment in the area on the two-dimensional drawing data detected by the detecting means is determined, and the determined auxiliary line is determined. A device for automatically generating an auxiliary line segment, comprising means for generating data representing minutes. 2. A method for automatically generating an auxiliary line segment on a two-dimensional drawing data representing a three-dimensional model to improve the comprehension of the two-dimensional drawing. A region where an auxiliary line segment appears is detected on the two-dimensional drawing data, a position where the auxiliary line segment is provided in the detected region on the two-dimensional drawing data is determined, and data representing the determined auxiliary line segment is generated. , Automatic generation method of auxiliary line segment. 3. A device for automatically generating, on a two-dimensional drawing representing a three-dimensional model, an auxiliary line segment for improving the comprehension of the two-dimensional drawing. Means for detecting an area in which a line segment appears on the two-dimensional drawing, and a position for providing an auxiliary line segment in the area on the two-dimensional drawing detected by the detecting means is determined, and the determined auxiliary line segment is generated. A device for automatically generating an auxiliary line segment, which is provided with: 4. A method for automatically generating, on a two-dimensional drawing representing a three-dimensional model, an auxiliary line segment for improving the comprehension of the two-dimensional drawing. An automatic auxiliary line segment that detects the area in which the line segment appears on the two-dimensional drawing, determines the position where the auxiliary line segment is provided in the detected area on the two-dimensional drawing, and generates the determined auxiliary line segment. Generation method. 5. The auxiliary line segment automatic generation device according to claim 1, wherein the auxiliary line segment includes a tangent line segment and a silhouette line segment. 6. A drawing data storage means for storing two-dimensional drawing data of at least three planes drawn by the orthographic projection method, knowledge for recognizing a three-dimensional model restored based on the two-dimensional drawing data. Knowledge storage means to store,
Recognition means for recognizing a three-dimensional model restored based on the two-dimensional drawing data by applying the knowledge stored in the knowledge storage means to the two-dimensional drawing data stored in the drawing data storage means, the recognition Auxiliary line segment area determining means for determining an area for generating an auxiliary line segment in a two-dimensional drawing based on the three-dimensional model recognized by the means,
End point determining means for determining at least two end points of the auxiliary line segment to be generated in the area determined by the auxiliary line segment area determining means, and an auxiliary line segment connecting the end points determined by the end point determining means A supplemental line segment automatic generation device for a two-dimensional drawing, comprising: 7. The automatic generation device for an auxiliary line segment in a two-dimensional drawing according to claim 6, wherein the three-dimensional model recognized by the recognition means includes a cylinder, a cone, a sphere, a ring and an oblique cylinder. 8. The apparatus for automatically generating an auxiliary line segment in a two-dimensional drawing according to claim 6, wherein the auxiliary line segment includes a straight line segment, a circle, an arc, an ellipse and an elliptic arc. 9. An auxiliary knowledge storage unit for storing auxiliary knowledge for determining whether or not an auxiliary line segment should be generated between the endpoints determined by the endpoint determination unit, and an auxiliary line based on the auxiliary knowledge. The auxiliary line segment generating means is for generating an auxiliary line segment when the determining means determines that an auxiliary line segment should be generated. , Claims 6 to 8
An automatic line segment generation apparatus for a two-dimensional drawing according to any one of 1. 10. The auxiliary knowledge storage means stores a plurality of types of auxiliary knowledge, and includes drawing data feature extraction means for extracting features of two-dimensional drawing data, and features of the extracted two-dimensional drawing data. 10. The two-dimensional drawing according to claim 9, further comprising: auxiliary knowledge selecting means for selecting an appropriate kind of auxiliary knowledge from a plurality of kinds of auxiliary knowledge stored in the auxiliary knowledge storage means based on Automatic line segment generation device. 11. A command inputting means for inputting a command for erasing an unnecessary auxiliary line segment or a command for generating a missing auxiliary line segment from among the generated auxiliary line segments, and the command inputting means. 9. An erasing / generating means for erasing or generating an auxiliary line segment in two-dimensional drawing data based on an input command, according to any one of claims 6 to 8.
Item: A device for automatically generating an auxiliary line segment in a two-dimensional drawing according to the item. 12. A command inputting means for inputting a command for erasing an unnecessary auxiliary line segment or a command for generating a missing auxiliary line segment from the generated auxiliary line segments, and the command inputting means. The automatic line segment automatic generation device for a two-dimensional drawing according to claim 9 or 10, further comprising: an updating unit that updates the auxiliary knowledge based on the command. 13. The auxiliary line segment in the two-dimensional drawing according to claim 6, wherein the automatic line segment automatic generation device in the two-dimensional drawing is configured by a computer system. Automatic generator. 14. Two-dimensional drawing data for at least three surfaces drawn by the orthographic projection method is stored in advance in a drawing data storage device, and a three-dimensional model to be restored is recognized based on the two-dimensional drawing data. Based on the two-dimensional drawing data by applying the knowledge stored in the knowledge storage device to the two-dimensional drawing data stored in the drawing data storage device by previously storing the knowledge for Recognizing the three-dimensional model to be restored, based on the recognized three-dimensional model, the area in which the auxiliary line segment is to be generated is defined in the two-dimensional drawing, and the auxiliary line segment to be generated in the above-specified area A method for automatically generating an auxiliary line segment in a two-dimensional drawing, wherein at least two end points are determined and an auxiliary line segment connecting the determined end points is generated. 15. The method for automatically generating an auxiliary line segment in a two-dimensional drawing according to claim 14, wherein the recognized three-dimensional model includes a cylinder, a cone, a sphere, an annulus and an oblique cylinder. 16. The method for automatically generating an auxiliary line segment in a two-dimensional drawing according to claim 14, wherein the auxiliary line segment includes a straight line segment, a circle, an arc, an ellipse, and an elliptic arc. 17. Auxiliary knowledge for determining whether or not an auxiliary line segment should be generated between the end points of the determined auxiliary line segment is stored in advance in an auxiliary knowledge storage device, and based on the auxiliary knowledge. 17. The auxiliary line segment according to claim 14, wherein it is determined whether or not the auxiliary line segment should be generated, and when it is determined that the auxiliary line segment should be generated, the auxiliary line segment is generated. A method for automatically generating an auxiliary line segment in a two-dimensional drawing. 18. The auxiliary knowledge storage device stores a plurality of types of auxiliary knowledge, extracts characteristics of two-dimensional drawing data, and based on the extracted characteristics of the two-dimensional drawing data, the auxiliary knowledge. 18. The method for automatically generating an auxiliary line segment in a two-dimensional drawing according to claim 17, wherein an appropriate type of auxiliary knowledge is selected from a plurality of types of auxiliary knowledge stored in a storage device. 19. An auxiliary line in two-dimensional drawing data based on an unnecessary auxiliary line segment erasing command or a missing auxiliary line segment generation command given from the outside The method for automatically generating an auxiliary line segment in a two-dimensional drawing according to any one of claims 14 to 18, which erases or generates a segment. 20. The auxiliary knowledge is updated on the basis of an instruction to delete an unnecessary auxiliary line segment out of the generated auxiliary line segments or an instruction to generate a missing auxiliary line segment, which is given from the outside. A method for automatically generating an auxiliary line segment in a two-dimensional drawing according to claim 17 or 18. 21. The automatic generation method for an auxiliary line segment in a two-dimensional drawing according to claim 14, wherein a computer system executes the automatic generation method for an auxiliary line segment in the two-dimensional drawing. . 22. Drawing data storage means for storing two-dimensional drawing data for three planes drawn by the orthographic projection method, and knowledge for recognizing a three-dimensional model restored based on the two-dimensional drawing data. By applying the knowledge stored in the knowledge storage means to the two-dimensional drawing data stored in the knowledge storage means and the drawing data storage means, a three-dimensional model restored based on the two-dimensional drawing data is recognized. Recognizing means, auxiliary line segment area determining means for determining an area for generating an auxiliary line segment in a two-dimensional drawing based on the three-dimensional model recognized by the recognizing means, area determined by the auxiliary line segment area determining means End point determining means for determining at least two end points of the auxiliary line segment to be generated, and supplementary connection between the end points determined by the end point determining means. A CAD / CAM system having an automatic generation function of auxiliary line segments in a two-dimensional drawing, which is provided with auxiliary line segment generation means for generating auxiliary line segments.