JPH02127786A - Two-dimensional expressing method for three-dimensional object - Google Patents

Abstract

PURPOSE:To easily execute the two-dimensional expression of a three- dimensional object to have surface information by allocating the desired surface information to the desired object area of a three-dimensional object surface on a three-dimensional coordinate system and executing the two-dimensional projection of this three-dimensional object. CONSTITUTION:A CAD device 1, a format transforming device 2, an operation processor 3, a color scanner 4 and a surface information storage device 5 are provided. The desired surface information are allocated to the desired subject area of the three-dimensional object surface on the three-dimensional coordinate system. Namely, since the allocation is executed on the three-dimensional coordinate system, the prepared surface information can be allocated in a form as they are. Then, since any information is available when the surface information are two-dimensional pictures, an arbitrary pattern to be inputted by the color scanner 4, etc., can be utilized. Thus, the two-dimensional picture can be easily obtained by the two-dimensional projection of the three-dimensional object, to which the surface information are allocated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a two-dimensional representation method of a three-dimensional object, and particularly to a two-dimensional representation method of a three-dimensional object using image processing by a computer.

[Conventional technology]

In architecture and interior design, it is necessary to draw exterior and interior drawings and present them to customers. Such drawings include
Various three-dimensional objects such as doors, windows, and furniture will be drawn, and these three-dimensional objects have surface information such as wood grain patterns, fabrics, and metal surfaces. In the past, the creation of such drawings had to be done manually by a designer, but in recent years, methods using computer systems using CAD have been attempted.

[Problem to be solved by the invention]

However, the manual method of designing and designing requires a lot of labor and time, and has the problem of poor work efficiency. In addition, with the currently known methods using CAD, efficient methods are being realized for designing three-dimensional shapes, but methods for forming two-dimensional images of three-dimensional objects with surface information are not efficient. The situation is that no good method has been proposed. In particular, there is no known efficient method for producing two-dimensional displays with textures such as wood grain patterns, cloth, and metal surfaces.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method that can efficiently display a three-dimensional object having surface information in two dimensions.

[Means to solve the problem]

The present invention provides a method for expressing a three-dimensional object with surface information on a two-dimensional plane, which includes the steps of designing a three-dimensional object on a three-dimensional coordinate system and obtaining shape data of the three-dimensional object; A step of displaying a wire frame of the three-dimensional object on a two-dimensional plane based on the shape data, a step of creating surface information of the three-dimensional object, and a step of displaying a partial area of the surface of the three-dimensional object based on the wire frame display. a step of specifying the target area as a target area, a step of assigning surface information to the target area on a three-dimensional coordinate system and obtaining three-dimensional shape data of a three-dimensional object with surface information, and a step of specifying the three-dimensional shape obtained in the previous step. The method is designed to perform the steps of two-dimensionally projecting the data and obtaining a two-dimensional image.

[For production]

In the method according to the present invention, desired surface information is assigned to a desired target region on the surface of a three-dimensional object on a three-dimensional coordinate system. Since the layout is performed on a three-dimensional coordinate system, the prepared surface information can be allocated as is. Also,
Since the surface information may be any information as long as it is a two-dimensional image, any pattern input using a color scanner or the like can be used. A two-dimensional image can be easily obtained by two-dimensionally projecting a three-dimensional object to which surface information has been assigned in this manner.

〔Example〕

The present invention will be described below based on illustrated embodiments. 1st
The figure is a flowchart of a method according to an embodiment of the present invention, and the second
The figure is a block diagram showing the configuration of an apparatus for carrying out the procedures in this flowchart. First, the block diagram shown in FIG. 2 will be explained. The CAD device 1 is a device capable of designing a general three-dimensional shape, and a desired three-dimensional shape is defined in a three-dimensional coordinate system by this device. The three-dimensional shape data defined here is given to the arithmetic processing device 3 via the format conversion device 2. This arithmetic processing unit 3 is specifically constituted by a processing system within the host combiner. The format conversion device 2 has a function of converting three-dimensional shape data created in the data format in the CAD device 1 to the data format in the arithmetic processing device 3.

On the other hand, the color scanner 4 functions to input surface information to be assigned to the object surface. For example, when a wood grain pattern is captured by this color scanner 4, the data of the captured wood grain pattern is converted into two-dimensional image data to the arithmetic processing unit 3.
sent to. This wood grain pattern data can be stored in the surface information storage device 5 and read out by the arithmetic processing device 3 whenever necessary. The arithmetic processing unit 3 has the function of executing various processes to be described later, displays the processing progress on a graphic display 6 to provide necessary information to the operator, and inputs instructions from the operator from the peripheral input device 7. do. As the peripheral input device 7, a tablet, a function key, a dial input device, or the like is used. The two-dimensional image finally obtained by the arithmetic processing device 3 is outputted by the color hard copy device 8 to obtain a hard copy.

Next, the processing according to the present invention will be explained with reference to the flowchart of FIG. First, in step S1, the shape of a three-dimensional object is designed. This is a work performed by the CAD device 1, and a three-dimensional object is defined on a three-dimensional coordinate system. Specifically, shape data is generated as a set of coordinate values in a three-dimensional coordinate system. For example, in the case of a cube as shown in FIG. 3, the shape data is a set of three-dimensional coordinate values of its eight vertices and data indicating the relationship between these eight vertices. The method for generating this shape data is well known as a general CAD technique, so its explanation will be omitted here.

Next, in step S2, format conversion of the generated shape data is performed. This is because the CAD device 1 and the arithmetic processing device 2 generally have different data formats. This process is not necessary if the data format is common. The format-converted shape data is taken into the arithmetic processing unit 3.

Subsequent steps S3 and subsequent steps are processed by the arithmetic processing unit 3. First, in step S3, a wire frame display is performed based on the given shape data. This display is made on the graphic display 6.

FIG. 5 is a diagram showing an example of a display screen of the graphic display 6. As shown in FIG.

Here, the display screen is divided into an object display area 61, a surface information display area 62, and a command display area 63. The object display area 61 displays a two-dimensional projected image of a three-dimensional object to be processed, the surface information display area 62 displays a two-dimensional image to be assigned to the object surface, and the command display area 63 displays a two-dimensional projected image of a three-dimensional object to be processed. The various commands needed to do this will be displayed.

Let us now continue the explanation assuming that a cubic shape as shown in FIG. 3 is generated in step S1. A wire frame display is obtained by determining a viewpoint on a three-dimensional coordinate system and two-dimensionally projecting a three-dimensional object from this viewpoint position. Therefore, the wire frame display for the cubic shape as shown in FIG.
)become that way. If the operator does not like this display, he can obtain a different display by changing the viewpoint position using commands in the command display area 63. Note that various methods are known for projecting an object in a three-dimensional coordinate system onto a two-dimensional coordinate system based on a predetermined viewpoint position.

Once the wire frame is displayed, hidden line removal processing is performed in step S4. That is, the image shown in FIG. 4(b) is obtained from the image shown in FIG. 4(a). Since various methods for eliminating hidden lines are known, their explanation will be omitted here.

Next, in step S5, whether to allocate a pattern or not,
Decide whether to perform coloring treatment. The operator will specify one of them by inputting a command. After specifying the pattern layout, a pattern is selected in step S6. This selection may be made by displaying several patterns in the surface information display area 62, as shown in FIG. 4(C). The picture displayed here is based on image information input by the color scanner 4 and stored in the surface information storage device 5. The operator selects a desired pattern, such as a wood grain pattern or a polka dot pattern, from among the displayed patterns. This selection is easy to operate if the desired pattern is specified using the cursor C1 within the surface information display area 62, as shown in FIG. 4(d).

Next, in step S7, a layout plane is specified. This specifies which surface of the object the pattern is to be allocated to. Since the object is already displayed as a wire frame on the display screen, it is only necessary to designate the closed area surrounded by the wire as the layout plane. Specifically, as shown in FIG. 4(d), the object display area 61
A cursor C2 is displayed within the screen, and by moving the cursor C2, a desired layout surface can be specified. In the example shown in FIG. 4D, the layout plane S1 is designated by the cursor C2.

After a picture is selected in step S6 and a layout surface is designated in step S7, layout processing is performed in step S8. However, this allocation is performed on a three-dimensional coordinate system as follows. First, as shown in FIG. 5(a), a layout plane S1 is extracted on a three-dimensional coordinate system, and a plurality of pixels are defined on this layout plane S1. Each pixel has a three-dimensional coordinate value indicating its position. For example, in Figure 5 (a
) also has coordinate values (X, Y, Z) p
p p one. Note that in the figure, for convenience of explanation, one pixel is shown as a fairly large closed area, but in reality, one pixel is a small area that is recognized as a point.

On the other hand, as shown in FIG. 5(b), the pattern E to be allocated
is originally composed of a set of pixels, and each pixel has two-dimensional coordinate values. For example, pixel Q is (x
, y). If the pixels on the layout surface Sl and the pixels on the pattern E are arranged at the same pitch, a one-to-one correspondence will be created between the two pixels. For example, Fig. 5(a)
The pixel P in the figure corresponds to the pixel Q in FIG. This correspondence relationship can be determined by calculation from the coordinate values of each pixel.

Incidentally, each pixel Q constituting the picture E should be given some color value. Therefore, the color value of any pixel P on the layout surface S1 can be determined based on the color value given to the corresponding pixel Q on the pattern E. If necessary, the final color value can also be determined by assuming a light source in a three-dimensional coordinate system and taking into account the position of this light source and the color of the light source. Such a method for determining color values is described in, for example, Japanese Patent Laid-Open No. 10774/1983.

When such color value determination is performed for all pixels on the layout surface Sl, the layout process is completed. When the layout processing is completed, a set of pixels on a three-dimensional coordinate system having each color axis is two-dimensionally projected and displayed on the graphic display 6, thereby obtaining an image as shown in FIG. 4(e).

On the other hand, if coloring processing is specified in step S5, color selection is performed in step S9. This is for example R
All you have to do is input the color values of each of the three primary colors of GB from the keyboard. Subsequently, in step S10, a colored surface is specified. This can be done by specifying the colored surface S3 using the cursor C3 as shown in FIG. 4(f'). Next step Sll
In the coloring process, a specified color is applied to a specified colored surface. That is, for each pixel constituting the colored surface S3,
A color value corresponding to the designated color is given, and by displaying the two-dimensional projected image again, an image as shown in FIG. 4(g) is obtained.

As described above, the pattern assignment process or coloring process is repeatedly performed for each side (step 512). When the processing for all surfaces is completed, a two-dimensional image is output in step S13. That is, a two-dimensional projected image is output by the color hard copy device 8,
This hard copy will be presented to the customer. In addition,
If the data of each pixel in the three-dimensional coordinate system is stored, by reading this data, it is possible to easily respond to changes in layout patterns, color changes, etc. according to customer requests.

〔Effect of the invention〕

As described above, in the method according to the present invention, desired surface information is assigned to a desired target area on a three-dimensional object surface on a three-dimensional coordinate system, and this is two-dimensionally projected. It becomes possible to easily express two-dimensional objects.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the steps of an embodiment of the two-dimensional representation method for a three-dimensional object according to the present invention, FIG. 2 is a block diagram of a system suitable for carrying out the steps in FIG. 1, and FIG. is CA
A diagram showing an example of a three-dimensional object designed by the D device,
FIG. 4 is a diagram showing an example of a display screen by the apparatus shown in FIG. 2, and FIG. 5 is a diagram illustrating the principle of the allocation process in step S8 of FIG. 1. 61...Object display area, 62...Surface information display area, 63...Command display area, 01-C3...Cursor, P, Q...Pixels. Applicant's agent Hiroshi Shimura Figure 2, Drawing 3, Figure 4

Claims (1)

[Claims] A method for representing a three-dimensional object with surface information on a two-dimensional plane, the method comprising designing a three-dimensional object on a three-dimensional coordinate system and obtaining shape data of the three-dimensional object. a step of displaying the three-dimensional object as a wire frame on a two-dimensional plane based on the shape data; a step of creating surface information of the three-dimensional object; and a step of displaying the three-dimensional object on a two-dimensional plane based on the shape data; specifying a partial region of the surface of the original object as a target region; allocating the surface information to the target region on the three-dimensional coordinate system to obtain three-dimensional shape data of the three-dimensional object having surface information; A two-dimensional representation method for a three-dimensional object, comprising: a step of two-dimensionally projecting the three-dimensional shape data obtained in the previous step to obtain a two-dimensional image.