JP4158959B2 - Three-dimensional shape processing apparatus, three-dimensional shape processing method, and recording medium on which program according to the method is recorded - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projection curve generation process using a three-dimensional shape processing apparatus such as a CAD / CAM apparatus, and more particularly to a projection curve generation process in which a curve is projected in a normal direction onto a concave conical surface.
[0002]
[Prior art]
Conventionally, in a CAD / CAM device using a graphics display device and a computer, a curve above a three-dimensional solid curved surface is projected in a normal direction with respect to the curved surface by the following procedure. The three-dimensional solid refers to, for example, a shape generated as solid model data in a boundary representation format. The solid model in a boundary representation format is closed in a three-dimensional space by elements such as edges, vertices, and faces. This is a representation of a solid with a defined area.
(1) Several points including both end points are extracted from the curve, and a perpendicular line is drawn from each point on the curved surface (see FIG. 6).
(2) The points on the curved surface of the perpendicular line drawn on the curved surface are smoothly connected to generate a curve (projection curve) that rides on the curved surface (see FIG. 7).
That is, a curved line is approximately projected by generating a curved line by connecting several projected points. However, in the above-described prior art, since points are extracted from the entire curve without considering whether the points can be projected on the curved surface, when points that cannot be projected are extracted, there are other points that can be projected. Even if it existed, the curve could not be projected onto the curved surface (see FIG. 8). For example, if the curved surface is a concave conical surface, if the curve intersects or overlaps the axis of the conical surface, the perpendicular line drawn from the point extracted from such a point is not uniquely determined, so we try to find it The projection curve to be determined is not determined (see FIG. 9).
[0003]
[Problems to be solved by the invention]
As described above, in the prior art, when the curved surface is, for example, a concave conical surface, if the curve on such a curved surface intersects or overlaps the axis of the conical surface, the point extracted from such a point Since the perpendicular to be lowered is not uniquely determined, even if there are other points that can be projected, the entire curve was treated as being unable to be projected onto the curved surface.
An object of the present invention is to solve such a problem of the prior art. When a curved surface is a concave conical surface, a projectable portion on the curve is examined, and a projection curve is obtained for the projectable portion. Another object of the present invention is to provide a three-dimensional shape processing method.
[0004]
[Means for Solving the Problems]
To solve the problems described above, a first aspect of the present invention, in the three-dimensional shape processing apparatus which can be projected in the normal direction of the curve against the concave conical surface, the shaft and its cone conical surface A plane generating means for generating a plane on which the generatrix that is the boundary line at one end of the surface rides, a plane on which the generatrix and the axis of the conical surface at the other end of the conical surface are on, and a curve to be projected are generated. The curve dividing means for dividing the curve into the projectable part existing on either side of the two planes and the non-projectable part existing on at least one of the two planes, and the curve dividing means divided by the curve dividing means extracting several points including the end points from the projection moiety, a projection curve generating means for generating a projected curve on the conical surface from the points extracted, characterized by comprising a.
Invention 請 Motomeko 2 is a three-dimensional shape processing method in the three-dimensional shape processing apparatus which projects in the direction normal to the curve with respect to the concave conical surface, the one end of the shaft and its conical surface of the conical surface A plane generation process for generating a plane on which a generatrix that is a boundary line rides, and a plane on which a generatrix and an axis of the cone surface on which the other end of the conical surface rides, and a curve to be projected, A curve dividing step for dividing a curve into a projectable part existing on either side of the plane and a non-projectable part existing on at least one of the front sides, and a projectable part divided by the curve dividing means And a projection curve generation step of generating a projection curve on each conical surface from each of the extracted points .
Invention 請 Motomeko 3, in the three-dimensional shape processing method according to claim 2, wherein, by the said the axis of the conical surface curve to see if it intersects, the curve has a step of determining if possible the projection It is characterized by.
Invention 請 Motomeko 4, in the three-dimensional shape processing method according to claim 2 or 3, wherein, by checking whether said the axis of the conical surface curves overlap, the step of curve investigate whether projectable It is characterized by having .
Invention 請 Motomeko 5, claim 2, 3, or in the three-dimensional shape processing method according to any one of 4, when the curve includes a part that can not be projected on a curved surface, only the curved projection moiety It has the process to project, It is characterized by the above-mentioned.
Invention 請 Motomeko 6 is a computer-readable recording medium, the steps of the three-dimensional shape processing method according to any one of claims 2 to 5, a program for implementing the function of the computer characterized in that it has been recorded.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a block diagram showing the configuration of a three-dimensional shape processing apparatus showing an embodiment of the present invention. As shown in the figure, the three-dimensional shape processing apparatus of this embodiment includes three-dimensional shape data acquired by inputting from the outside, such as a system control unit 1 that controls the entire apparatus, and a projection curve generation process according to the present invention. 3D shape processing unit 2, an external storage device (for example, a hard disk device) 3 for storing 3D shape data and programs, etc., and a graphic display device 4, 3 for displaying a 3D solid shape according to the 3D shape data A plotter 5 for outputting a three-dimensional solid shape or the like on paper, an operation display unit 6 having a keyboard, a mouse, a text display device, etc., a communication control unit 7 for acquiring three-dimensional shape data from the outside via a network, etc. ing.
The system control unit 1 and the three-dimensional shape processing unit 2 have a memory (for example, a RAM) that temporarily stores a program according to the present invention and various data, and a CPU that operates according to the program. In this embodiment, the plane generating means, the curve dividing means, and the projection curve generating means described in claim 1 are realized by the three-dimensional shape processing unit 2.
With such a configuration, in the three-dimensional shape processing apparatus of this embodiment, when a curve on a concave conical surface constituting a three-dimensional solid shape is projected onto the conical surface, a projectable portion on the curve And a projection curve is obtained for the projectable part.
[0006]
FIG. 1 shows an operation flow of an embodiment of the present invention. The operation of this embodiment will be described below with reference to FIG.
First, the three-dimensional shape processing unit 2 creates a plane a as shown in FIG. 3 (S1). That is, a plane a on which the axis c of the concave conical surface and one generatrix of the conical surface (a boundary line at one end of the conical surface is a straight line) is created (FIG. 3: the axis of the conical surface). (See the view from the direction). Further, the three-dimensional shape processing unit 2 also creates a plane b on which the other generatrix and the axis c of the conical surface ride (S2) (see FIG. 3). Focusing on the generatrix on the plane, the side where the conical surface exists is the back side of the plane, and the side where the conical surface does not exist is the front side of the plane.
Subsequently, the three-dimensional shape processing unit 2 has a portion to be projected on the back side of either of the two planes (portion A shown in FIG. 4) and at least one of the curves to be projected. The curve is divided into a portion existing on the front side (portion B shown in FIG. 4) (S3). Note that the portion where the curve intersects the plane is considered to exist on the back side.
Thus, if the portion A exists in the curve and the portion does not intersect or overlap the cone axis, it is determined that the portion can be projected (Yes in S4) (see FIG. 5). ). The point where the curved line intersects the plane is an end that can be projected, but the straight line that extends from the point in the normal direction of the curved surface with respect to the conical surface is on the plane. And the point where the curved surface (conical surface) intersects does not protrude from the curved surface.
Subsequently, the three-dimensional shape processing unit 2 extracts a number of points including both end points of the A portion that is considered to be projectable (S5), and a concave conical surface is extracted from each point. A perpendicular line is dropped (S6). Further, a plurality of perpendicular feet (points on the conical curved surface of the vertical line) drawn down on the curved surface are smoothly connected (S7) to generate a projection curve of the projectable portion.
On the other hand, when it is determined in step S4 that there is no projectable portion (No in S4), this operation flow is terminated at that time.
Thus, according to this embodiment, only a projectable portion can be generated to generate a projection curve. Therefore, a perpendicular line that is going to be dropped from an accidentally extracted point on the projected curve is not uniquely determined. In spite of the fact that there are other points that can be projected, the problem that any part of the curve cannot be projected onto the curved surface can be solved.
[0007]
The three-dimensional shape processing method of the present invention has been described above with respect to one embodiment. For example, a program programmed to realize each step of the three-dimensional shape processing method as described above as a computer function can be attached or detached. by then recorded in a computer-readable record medium, mounting the record medium to a personal computer such as an information processing apparatus that has not performed the projection curve generation was by the present invention heretofore, the present also in the information processing apparatus Projection curve generation according to the invention can be performed. In addition, the program can be transferred to an information processing apparatus via a network, and the information processing apparatus can also generate a projection curve according to the present invention.
[0008]
【The invention's effect】
As described above, according to the present invention, according to the first and second aspects of the present invention, in the three-dimensional shape processing method for projecting a curve in a normal direction with respect to a concave conical surface, A plane where one generatrix and the axis of the conical surface ride is generated for two generatrix lines, and by using the two generated planes, the projected curve is divided into a projectable part and a non-projectable part. Since only the projection line can be generated, the perpendicular line to be dropped from the extracted point on the curve to be projected is not uniquely determined. A problem that any part of the curve cannot be projected onto the curved surface can be solved.
Further, in the invention described in claim 3, in the invention described in claim 2, it is examined whether or not the axis of the conical surface and the curve intersect, and the result is also taken into consideration to determine whether or not the curve can be projected. Therefore, the determination of whether or not the projection is possible becomes more strict, and therefore it is not possible to project when the projection operation is performed even though it is determined that the projection is possible. Will not occur.
Further, in the invention described in claim 4, in the invention described in claim 2 or claim 3, whether or not the axis of the conical surface and the curve overlap is examined, and whether or not the curve can be projected in consideration of the result. In the same manner or in addition, the determination as to whether or not projection is possible becomes strict, and therefore it is determined that projection is possible but projection is impossible when projection is performed. This eliminates unnecessary work.
[0009]
Further, in the invention according to claim 5, in the invention according to claim 2, claim 3, or claim 4, when the curve includes a portion that cannot be projected onto a curved surface, only the projectable portion is projected onto the curved surface. When the projecting operation is performed, there is no such a situation that the projection could not be performed, and therefore no unnecessary work is generated. Further, in the sixth aspect of the present invention, since the program programming is recorded for example on a removable record medium in accordance with the three-dimensional shape processing method according to any one of claims 2 to 5, the record By mounting a medium on an information processing apparatus such as a personal computer that has not been able to generate a projection curve according to any of claims 2 to 5, the information processing apparatus also includes claims 2 to 5. The effect of any of the inventions of 5 can be obtained.
[Brief description of the drawings]
FIG. 1 is an operation flowchart of a projection curve generation method executed by a three-dimensional shape processing apparatus showing an embodiment of the present invention.
FIG. 2 is a configuration block diagram of a three-dimensional shape processing apparatus showing an embodiment of the present invention.
FIG. 3 is an explanatory diagram of a projection curve generation method showing an embodiment of the present invention.
FIG. 4 is another explanatory diagram of a projection curve generation method showing an embodiment of the present invention.
FIG. 5 is another explanatory diagram of a projection curve generation method showing an embodiment of the present invention.
FIG. 6 is an explanatory diagram of a projection curve generation method showing an example of a conventional technique.
FIG. 7 is another explanatory diagram of a projection curve generation method showing an example of the prior art.
FIG. 8 is another explanatory diagram of a projection curve generation method showing an example of the prior art.
FIG. 9 is another explanatory diagram of a projection curve generation method showing an example of the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 System control part 2 3D shape processing part 3 External storage device 4 Graphics display apparatus 5 Plotter 6 Operation display part 7 Communication control part

Claims (6)

In a three-dimensional shape processing apparatus capable of projecting a curve in a normal direction with respect to a concave conical surface,
Planar axis as generatrix which is one end of the boundary line of the conical surface of the conical surface rides and a plan generating means for generating a plane shaft generatrix and the conical surface ride the boundary line of the other end of the conical surface, the projection A curve dividing means for dividing the curve into a projectable part existing on either side of the two generated planes and a non-projectable part existing on at least one of the front surfaces of the generated curve; characterized in that to extract some of the points, a projection curve generating means for generating a projected curve on the conical surface from each point extracted, with a from the divided projection moiety by curve dividing means including two end points A three-dimensional shape processing apparatus. The curve with respect to the concave curved conical surfaces a three-dimensional shape processing method in the three-dimensional shape processing apparatus which projects in a normal direction,
A plane generating step for generating a plane on which the axis of the conical surface and the generatrix which is the boundary line at one end of the conical surface ride, and a plane on which the axis of the conical surface and the generatrix line at the other end of the conical surface are superimposed, and projection A curve dividing step of dividing a curve into a projectable part existing on either side of the two generated planes and a non-projectable part existing on at least one front side of the generated curve; to Yes an extraction step of extracting a number of respects, including two end points from the divided projection moiety by curve dividing means, a projection curve generating step of generating a projected curve on the conical surface from each point extracted, the A three-dimensional shape processing method. The three-dimensional shape processing method according to claim 2,
A three-dimensional shape processing method comprising a step of examining whether or not a curve can be projected by examining whether or not an axis of a conical surface and the curve intersect. In the three-dimensional shape processing method according to claim 2 or 3, wherein,
A three-dimensional shape processing method comprising a step of examining whether or not a curve can be projected by examining whether or not a conical surface axis and the curve overlap. Claim 2, 3, or in the three-dimensional shape processing method according to any one of 4,
When the curved line includes a portion that cannot be projected onto a curved surface, the method includes a step of projecting only a portion that can be projected onto a curved surface. 請 Motomeko the steps of the three-dimensional shape processing method according to any one of 2 to 5, a computer-readable record medium, characterized in that the program has been recorded for realizing the functions of the computer.

Images