JP4675129B2 - Three-dimensional shape processing apparatus, three-dimensional shape processing method, program, and recording medium - Google Patents

Description

  The present invention relates to a three-dimensional shape processing apparatus, a three-dimensional shape processing method, a program, and a recording medium, and more specifically, three-dimensional shape processing / highlighting a line of intersection of two planes forming a sharp angle of a three-dimensional shape model. The display technology is suitable for 3D shape processing / display technology in a 3D CAD / CAM / CAE / CG system or the like.

With the spread of 3D CAD / CAM / CG systems and the like, the number of users of 3D shape data has expanded, and opportunities for effective use of 3D shape data have increased.
In such a system, the shape is grasped by displaying three-dimensional shape data on a display device or the like. When you want to find a specific part, the part is highlighted or displayed.

  For example, when it is desired to emphasize a contour line, in Patent Document 1, CAD data and non-contact measurement point data previously aligned with CAD data are recorded, an analysis surface having a predetermined shape is extracted from CAD data, and analyzed. Surface generation is performed using the surface and non-contact measurement point data, and an intersection line between the generated surfaces is extracted as a contour line. Thereby, the influence by the variation of non-contact measurement point data can be suppressed, more accurate contour extraction can be performed, and the contour line of the corner having an acute angle can be accurately extracted.

  Further, in Patent Document 2, whether each pixel constituting each side of the projected polygon included in the display image is a pixel constituting a ridge line that is a side shared by the two projected polygons. It is determined whether the pixel constitutes a contour line that is a side of one projected polygon, and the brightness of the display image after projection of each pixel of the pixel constituting the contour line and the pixel constituting the ridge line is determined. On the other hand, the luminance of the display image after projection is modulated according to the luminance modulation method designated by the designation means among the plurality of luminance modulation methods predetermined for each of the pixels constituting the contour line and the pixels constituting the edge line. Like to do. Thereby, since a contour line and a ridgeline can be emphasized, it becomes easy to understand a three-dimensional object shape.

In Patent Document 3, when a boundary curve of a NURBS curved surface arranged in a three-dimensional space is displayed on a display device, first, whether or not the control points of the boundary curves of two adjacent NURBS curved surfaces completely match. judge. When it is determined that the control points of the curves do not match, a single curve is generated by merging the two curves, and the distance between the points on the curve and the tangent plane at the points when the original two curves are divided into N parts Calculate and assign a tangent plane to contact some points of the generated curve, generate a contact plane, generate a point from information obtained by multiplying the difference between the original two curves on the contact plane by a real number, and generate By generating an interpolation curve from the points, the minute distance between the curves is emphasized and displayed.
This eliminates the complexity of the program and makes it possible to intuitively understand the relationship between the entire shape and the part that you want to see in detail.
JP 2000-306111 A Japanese Patent Laid-Open No. 08-279057 JP 2001-351117 A

  On the other hand, when the completed three-dimensional shape touches human hands, there is a danger of accidental touching and injury if there are sharp points. In such a case, it is necessary to take measures such as removing such a part at the design stage or performing a process of rounding the tip.

  However, in the above-described conventional technology, it is impossible to perform highlighting when the angle formed by the two planes of the three-dimensional shape is equal to or less than a specified angle.

  The present invention has been made in consideration of the above situation, and is an intersection of two planes when the angle formed by the two planes placed in the same three-dimensional coordinate space is equal to or less than the specified angle. It is an object of the present invention to provide a three-dimensional shape processing apparatus, a three-dimensional shape processing method, a program, and a recording medium capable of visually distinguishing a pointed portion by highlighting.

In order to solve the above problems, the invention described in claim 1 is a three-dimensional shape processing apparatus for processing and displaying a three-dimensional shape model, and a shape data storage means for storing shape data of the three-dimensional shape model; The edge information extracting means for extracting the edge information of the designated three-dimensional shape model from the shape data storing means, and the edge information extracted by the edge information extracting means with reference to the shape data storing means. Calculating an angle formed by two three-dimensional planes sharing the edge information, and determining whether the angle is equal to or smaller than a predetermined angle and the specified three-dimensional shape model. when, a three-dimensional shape processing apparatus and a display means for highlighting the determined edges is below a pre-specified angle by said angle calculating means, said display means, previously designated angle than 2 plane intersection line forms an angle of, when overlapping the shaded displayed part of the three-dimensional model on the viewpoint side than the intersection line, characterized in that it does not display the intersection line.

According to a second aspect of the present invention, there is provided a three-dimensional shape processing method for processing and displaying a three-dimensional shape model, wherein the three-dimensional shape processing device is designated from shape data storage means for storing shape data of the three-dimensional shape model. Extracting the edge information of the three-dimensional shape model thus obtained, and referring to the shape data storage means for the extracted edge information, an angle formed by two three-dimensional planes sharing the edge information is determined. A three-dimensional shape processing method comprising: a step of calculating; and a step of highlighting the side of a three-dimensional shape model to be displayed when the angle is equal to or less than a predetermined angle. When the intersecting line of two planes forming an angle equal to or smaller than the angle specified in advance overlaps the portion of the 3D shape model that is closer to the viewpoint than the intersecting line, the intersection line is not displayed. It is characterized by that.

According to a third aspect of the invention, the computer is a program for realizing the functions of the three-dimensional shape processing apparatus according to claim 1 Symbol placement.
The invention according to claim 4 is a computer-readable recording medium storing the program according to claim 3 .

According to the present invention, sharp edges that are placed in the same three-dimensional coordinate space and whose angle between the two planes is less than the specified angle are highlighted, so that the sharp edges can be easily visually identified.
Further, since only the sharp edge when the two planes are convex is highlighted, the sharp edge that is convex can be easily discriminated when there are many irregularities.

Further, when a configuration is adopted in which a sharp edge hidden by the shadow of another surface is not displayed, it is possible to easily determine whether the sharp edge is protected by the other surface .

Hereinafter, preferred embodiments of the three-dimensional shape processing apparatus of the present invention will be described with reference to the drawings.
FIG. 1 is a hardware configuration diagram of a three-dimensional shape processing apparatus to which the present invention is applied. In FIG. 1, a three-dimensional shape processing apparatus includes a CPU 1 that operates according to a program, a memory (eg, ROM, RAM, etc.) 2 that temporarily stores the program and various data, and an external storage that stores the program and various data. A device (for example, a hard disk device) 3, a keyboard, a mouse, and the like are provided, an input device 4 for inputting various data including 3D shape data and instructions, a display device 5 for displaying a 3D shape model, and the like. .

FIG. 2 is a block diagram illustrating functions of the three-dimensional shape processing apparatus according to the present embodiment. In the figure, the three-dimensional shape processing apparatus includes a side information extraction unit 12, an angle calculation unit, in addition to a general function of performing three-dimensional shape processing using the three-dimensional shape data stored in the shape data storage unit 11. 13, a sharp edge storage unit 14 and a display unit 15.
Each of the above processing units is realized by the hardware and program as described above, and the shape data storage unit 11 and the sharp edge storage unit 14 use the external storage device 3, and the intermediate processing result of each processing unit. Is stored using the memory 2 or the external storage device 3.

When the three-dimensional shape model stored in the shape data storage unit 11 is designated, the side information extraction unit 12 performs processing according to the following procedure, and then passes control to the display unit 15.
Here, when the angle formed by the two planes in the three-dimensional shape model with respect to the designated three-dimensional shape model and a preset angle ε (threshold for determining an acute angle) is equal to or less than the threshold ε, The intersection of these two planes is defined as a sharp edge.

(1) Referring to the shape data storage unit 11, information on one side is extracted from the specified three-dimensional shape model.
The edge extraction method is a method of taking out one edge in a specified 3D shape model one by one, or extracting all edges in the 3D shape model to create a list, and taking out one edge from this list. There are methods.
(2) The extracted side is passed to the angle calculation unit 13 to determine whether the side is a sharp edge. When the side is a sharp edge, information on the side is stored in the sharp edge storage unit 14.
(3) The above (1) and (2) are processed for all the sides of the specified three-dimensional shape model.

  The angle calculation unit 13 performs the following processing to determine whether the passed edge is a sharp edge. If the edge is a sharp edge, the angle calculation unit 13 stores the edge in the sharp edge storage unit 14 and the edge information extraction unit 12. Return control to

(1) From the edge information passed from the edge information extraction unit 12, the coordinates of the end points (vertex C and vertex D) of the passed edge are extracted from the shape data storage unit 11 and stored in the memory 2.
(2) Two planes including the side CD are acquired from the shape data storage unit 11, two polygons including the side CD are taken out, and vertices (vertex A and vertex B) that are not the end points are stored in the memory 2. deep.
(3) The normal vector of the plane including vertex A (referred to as nA) and the normal vector of the plane including vertex B (referred to as nB) are respectively obtained from the shape data storage unit 11 and stored in the memory 2 (See FIG. 3). At this time, if each normal vector is not a unit vector, each vector is divided by its length to be a unit vector.
(4) The angle θ is calculated from the inner product αβ of the vector α connecting the vertex A and the vertex C and the vector β connecting the vertex B and the vertex C, and stored in the memory 2.
Here, as shown in FIG. 4, the components of the two vectors are respectively expressed as vectors α = (a ₁ , a ₂ , a ₃ ),
Vector β = (b ₁ , b ₂ , b ₃ )
Then, if the vectors α and β are not zero vectors, the angle θ can be obtained from the inner product αβ of the vectors α and β.

(5) The sum of the normal vectors nA and nB stored in the memory 2 is obtained and stored in the memory 2 as the vector nAB.
(6) Using this vector nAB and the component of the vector CA, the inner product of the two vectors is calculated by (Equation 1) to determine the unevenness of the angle formed by the two planes. The unevenness is convex if the inner product is a positive value (see FIG. 5A), concave if the inner product is a negative value (see FIG. 5B), and 2 if the inner product is 0. It is determined that the plane is 180 degrees.
(7) If the inner product of the vector AB and the vector CA is negative, the (360−θ) degree is set to an angle θ formed by the two planes.
When the inner product is positive or 0, the angle θ is an angle formed by two planes.
(8) When the angle θ is smaller than the preset threshold value ε, the edge information passed from the edge information extraction unit 12 is stored in the sharp edge storage unit 14 as a sharp edge.

  The display unit 15 causes the specified three-dimensional shape model displayed on the display device 5 to be highlighted on the sides stored in the sharp edge storage unit 14. At this time, as the highlight display, for example, one or more line colors, line widths, and line types are combined and displayed differently from the other sides.

If the user (1) always displays a hidden sharp edge, or (2) instructs the user not to display only the hidden sharp edge, the display unit 15 causes the display device 5 to display 3 When displaying the 3D shape model, if there is a portion where the sharp edge overlaps with the 3D shape model to be shaded and displayed on the viewpoint side from the sharp edge based on this instruction, the sharp edge is not displayed for the overlapping portion. .
Alternatively, the sharp edge is always displayed in the foreground even if there is a portion where the sharp edge overlaps with the three-dimensional shape model to be shaded and displayed on the viewpoint side of the sharp edge.

  FIG. 6 is an example of sharp edge emphasis display. In this example, a sharp edge (threshold ε is set to 90 degrees) is displayed by changing the color of the other side and the line (yellow) and the line width (thick line).

With the configuration as described above, sharp edges that are placed in the same three-dimensional coordinate space and whose angle between two planes is less than a specified angle are highlighted, so that the sharp edges can be easily visually identified. .
Further, since only the sharp edge when the two planes are convex is highlighted, the sharp edge that is convex can be easily discriminated when there are many irregularities.

Further, when a configuration is adopted in which a sharp edge hidden by the shadow of another surface is not displayed, it is possible to easily determine whether the sharp edge is protected by the other surface.
In addition, even when a sharp edge hidden by the shadow of another surface is displayed, it is possible to easily determine a sharp edge that is a shadow of another surface.

FIG. 7 is a flowchart for explaining processing for determining whether one side is a sharp edge in the angle calculation unit 13.
First, the edge information extraction unit 12 acquires edge information (step S1).
Next, the normal of the surface adjacent to the side and the coordinates of the polygon adjacent to the side are acquired from the shape data storage unit 11 from the side information passed from the side information extraction unit 12 (step S2).
That is, the coordinates of the end points of the handed sides (vertex C and vertex D, respectively) are extracted and stored in the memory 2. Subsequently, two planes including the side CD are acquired from the shape data storage unit 11, two polygons including the side CD are taken out, and vertices (vertex A and vertex B) that are not the end points are stored in the memory 2. deep. Then, the normal vector of the plane including the vertex A (referred to as nA) and the normal vector of the plane including the vertex B (referred to as nB) are extracted from the shape data storage unit 11 and stored in the memory 2.

  The angle θ is calculated from the inner product of the two vectors from the vector component connecting the vertex A and vertex C and the vector component connecting the vertex B and vertex C, and stored in the memory 2 (step S3).

Next, it is determined whether the angle formed by the two planes is convex or concave (step S4).
First, the sum of the normal vectors nA and nB stored in the memory 2 is taken. At this time, if each normal vector is not a unit vector, each vector is divided by its length to obtain a unit vector, and the sum of the vectors is obtained and stored as a vector nAB in a memory.
Then, the inner product of the two vectors is calculated from the vector nAB and the components of the vector CA using (Equation 1). If the inner product is a positive value, the angle formed by the two planes is convex. If the inner product is a negative value, the angle formed by the two planes is concave. If the inner product is 0, the angle formed by the two planes is 180 degrees. It is determined that

  If the inner product of the vector nAB and the vector CA is negative (YES in step S5), the (360−θ) degree is set to an angle θ formed by the two planes (step S6). On the other hand, when the inner product is positive or 0 (NO in step S5), the angle θ is set to an angle formed by two planes.

Finally, when the angle θ is equal to or smaller than the preset threshold value ε (YES in step S7), the handed side is assumed to be a sharp edge, and this side information is stored in the sharp edge storage unit 14 and the process is terminated ( Step S8).
On the other hand, when the angle θ is equal to or larger than the preset threshold value ε (NO in step S7), it is determined that the handed side is not a sharp edge, and the process ends.

The present invention is not limited only to the above-described embodiments. Each function constituting the three-dimensional shape processing apparatus of the above-described embodiment is programmed and written in a recording medium in advance, and these programs recorded on the recording medium are stored in a memory or a storage device provided in the computer. It goes without saying that the object of the present invention is achieved by storing and executing the program. In this case, the program itself read from the recording medium realizes the functions of the above-described embodiment, and the program and the recording medium recording the program also constitute the present invention.
In addition, the program includes a case where the functions of the above-described embodiment are realized by processing in cooperation with an operating system or another application program based on an instruction of the program.

Note that the program for realizing the functions of the above-described embodiments includes a disk system (for example, a magnetic disk, an optical disk, etc.), a card system (for example, a memory card, an optical card, etc.), and a semiconductor memory system (for example, a ROM, a nonvolatile memory). Etc.) and a recording medium of any form such as a tape system (for example, magnetic tape, cassette tape, etc.). Alternatively, the program stored in the storage device may be directly supplied from the server computer via the network. In this case, the storage device of this server computer is also included in the recording medium of the present invention.
As described above, by programming and distributing the functions of the above-described embodiment, the cost can be reduced, and the portability and versatility can be improved.

It is a hardware block diagram of the three-dimensional shape processing apparatus to which this invention is applied. It is a block diagram which shows the function of the three-dimensional shape processing apparatus which concerns on embodiment. It is a figure for demonstrating the normal vector in a polygon. It is a figure for demonstrating the inner product of two vectors. It is a figure for demonstrating the uneven | corrugated determination of the angle | corner which two planes make. It is a display example of a sharp edge. It is a flowchart for demonstrating the process which determines whether one edge | side is a sharp edge in an angle calculation part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... CPU, 2 ... Memory, 3 ... External storage device, 4 ... Input device, 5 ... Display apparatus, 11 ... Shape data storage part, 12 ... Edge information extraction part, 13 ... Angle calculation part, 14 ... Sharp edge storage part , 15 ... display section.

Claims (4)

In a three-dimensional shape processing apparatus for processing and displaying a three-dimensional shape model, shape data storage means for storing shape data of the three-dimensional shape model, and edge information of the designated three-dimensional shape model are obtained from the shape data storage means. For the edge information extracting means to be extracted and the edge information extracted by the edge information extracting means, refer to the shape data storage means and calculate an angle formed by two three-dimensional planes sharing the edge information. An angle calculating means for determining whether the angle is equal to or smaller than a predetermined angle; and when the specified three-dimensional shape model is displayed, the angle calculating means determines that the angle is equal to or smaller than a predetermined angle. A three-dimensional shape processing apparatus comprising: display means for highlighting the sides .
The display means, when an intersecting line of two planes forming an angle equal to or smaller than a predesignated angle overlaps with a portion of the 3D shape model that is closer to the viewpoint than the intersecting line, is displayed with the intersecting line. A three-dimensional shape processing apparatus that is not displayed .   In a three-dimensional shape processing method for processing and displaying a three-dimensional shape model, the three-dimensional shape processing apparatus receives edge information of the specified three-dimensional shape model from shape data storage means for storing shape data of the three-dimensional shape model. Extracting the edge information, referring to the shape data storage means, calculating an angle formed by two three-dimensional planes sharing the edge information, A three-dimensional shape processing method including a step of highlighting the side of a three-dimensional shape model to be displayed when the angle is equal to or less than a specified angle,
  In the step of displaying, when an intersecting line of two planes forming an angle equal to or smaller than a predesignated angle overlaps with a shaded display portion of the three-dimensional shape model located on the viewpoint side from the intersecting line, the intersecting line A three-dimensional shape processing method characterized by not displaying.   The program for making a computer implement | achieve the function of the three-dimensional shape processing apparatus of Claim 1.   A computer-readable recording medium storing the program according to claim 3.