JP2003242186A - Cad data processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire exact CAD data by utilizing position data obtained by measuring a three-dimensional model. <P>SOLUTION: The three-dimensional model 2 of a product is prepared by the CAD data 5 obtained by a design. A test for the characteristic of the three- dimensional model 2 is performed and a shape is corrected by a manual work as necessary. The three-dimensional model 2 is measured by a three-dimensional scanner 23 to acquire point group data 15. A parameter in the CAD data 5 is corrected to be compatible with the point group data 15 within a prescribed range to obtain new CAD data 35. Since a plurality of parameters of unit shape elements in the CAD data 5 are corrected based on a measuring result of the three-dimensional model 2, the exact new CAD data 35 corresponding to the three-dimensional model 2 can be acquired. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CAD data processing apparatus, method and program, and more particularly to CAD data processing apparatus and method which can correct CAD data by using position data obtained by measuring a stereo model.

[0002]

2. Description of the Related Art CAD (Computer Aided Design) is widely used for designing parts and products, and a method of manufacturing a three-dimensional model by laminating, for example, a photocurable resin using CAD data is also widely used. There is. Such a three-dimensional model is called a rapid prototype, and is useful when a prototype having a fine shape such as an intake port of an internal combustion engine is quickly prototyped.

[0003]

By the way, when performing a subtle correction such as putting putty material on the three-dimensional model while conducting an experiment with the actual three-dimensional model created from the CAD data in this way, this correction is performed. Is not always easy to reflect in the original CAD data.

That is, by measuring a three-dimensional model with a three-dimensional measuring device, it is possible to obtain point cloud data which is position data for a large number of measurement points. From this point cloud data, a 3D model based on polygons or NURBS planes It is possible to create. However, the point cloud data only defines the position coordinates of the surface, and the plane, circle, hole, fillet,
CAD data cannot be directly generated from the point cloud data because it does not include information related to manufacturing-required parameters such as.

Therefore, conventionally, in order to reflect the correction applied to the three-dimensional model in the CAD data, the CAD data is adjusted according to the correction amount.
This is extremely complicated because it is necessary to adjust the parameters of the data, create a three-dimensional model again by using the CAD data, perform an experiment with this three-dimensional model, and readjust the parameters of the CAD data again.

Therefore, an object of the present invention is to provide means for obtaining accurate CAD data by utilizing position data obtained by measuring a three-dimensional model.

[0007]

According to a first aspect of the present invention, a CAD data storage unit for storing CAD data of a three-dimensional model composed of a plurality of shape elements and the three-dimensional model corresponding to the CAD data are measured. A measurement data storage unit that stores the position data of the measurement point group obtained by the above, an extraction unit that extracts the measurement point group corresponding to each of a plurality of shape elements included in the CAD data, and an extraction unit that extracts the measurement point group. A CAD data processing device, comprising: a correction processing unit that corrects the parameter of the shape element in the CAD data so as to match the position of the measured point group within a predetermined range.

In the first aspect of the present invention, the extraction means extracts a measurement point group corresponding to each of the plurality of shape elements included in the CAD data from the measurement data storage section. Then, the correction processing unit corrects the parameter of the shape element in the CAD data so that the position of the extracted measurement point group fits within the predetermined range. Thus, in the first aspect of the present invention, CA
Since the parameters of the plurality of shape elements in the D data are corrected based on the measurement result of the three-dimensional model, accurate CAD data corresponding to the three-dimensional model can be acquired by this.

A second aspect of the present invention is the CAD data processing apparatus according to the first aspect of the present invention, wherein the extracting means includes an aligning means for aligning the CAD data with the position data of the measurement point group. A CAD data processing device comprising: a measurement point group within a predetermined distance from a shape element of the CAD data, of the measurement point group after alignment.

In the second aspect of the present invention, the extraction means is provided with a positioning means for positioning the CAD data and the position data of the measurement point group, and the shape of the CAD data in the measurement point group after the positioning. Since the measurement point group within a predetermined distance from the element is extracted, this makes it easy to extract the measurement point group.

A third aspect of the present invention is the CAD data processing apparatus according to the first or second aspect of the present invention, wherein the correction processing means determines the distance between the extracted measurement point group and the shape element. The CAD data processing device is characterized in that the parameters are corrected so that the total falls within a predetermined range from the minimum value.

According to a third aspect of the present invention, the correction processing means adjusts the shape elements so that the total distance between the extracted measurement point group and the shape elements in the CAD data is within a predetermined range from the minimum value. As the parameters are corrected, this allows accurate CA
D data can be acquired.

A fourth aspect of the present invention is the CAD data processing device according to any one of the first to third aspects of the present invention, which is a gap detecting means for detecting a gap between the plurality of shape elements caused by the correction. And a correction processing means for correcting the detected gap, the CAD data processing device.

In the fourth aspect of the present invention, the gap detecting means detects the gap between the plurality of shape elements caused by the correction by the correction processing means, and the correction processing means corrects the detected gap. It is preferable because the detection and the correction can be automatically performed.

According to a fifth aspect of the present invention, there are provided CAD data of a three-dimensional model composed of a plurality of shape elements and position data of a measurement point group obtained by measuring the three-dimensional model corresponding to the CAD data. An extraction step of extracting a measurement point group corresponding to each of a plurality of shape elements included in the CAD data based on the above, and a step of extracting the measurement point group corresponding to the position of the extracted measurement point group within a predetermined range. A CAD data processing method including a correction processing step of correcting a parameter of a shape element. In the fifth aspect of the invention, the same effect as that of the first aspect of the invention can be obtained.

A sixth aspect of the present invention is the CAD data processing method according to the fifth aspect of the present invention, wherein the three-dimensional model is created based on the CAD data.

In the sixth aspect of the present invention, since accurate CAD data can be obtained by performing correction processing on the CAD data used for creating the three-dimensional model, it is necessary to newly create CAD data matching the three-dimensional model. Therefore, the number of steps can be suppressed.

According to a seventh aspect of the present invention, there are provided CAD data of a three-dimensional model composed of a plurality of shape elements, and position data of a measurement point group obtained by measuring the three-dimensional model corresponding to the CAD data. An extraction step of extracting a measurement point group corresponding to each of a plurality of shape elements included in the CAD data based on the above, and a step of extracting the measurement point group corresponding to the position of the extracted measurement point group within a predetermined range. A program for causing a computer to execute a correction processing step of correcting a parameter of a shape element. In the seventh aspect of the invention, the same effect as that of the first aspect of the invention can be obtained.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. In FIG. 1, a CAD data processing device 1 is a CAD generated by a CAD input device 3.
New CAD data 3 reflecting the shape of the stereo model 2 by using the data 5 and the point cloud data 15 which is the measurement point data of the stereo model 2 input by the point cloud data input device 4.
5 is generated. Although the non-contact type three-dimensional scanner 23 is used to acquire the point cloud data 15, a contact type measuring device may be used.

The CAD data processing device 1 is a well-known personal computer, and as shown in FIG. 2, includes a CPU (Central Processing Unit) 20 for controlling the inside of the device, a display device 24, an input device 25, and the like. CPU
An input / output control unit 21 for connecting with 20, an operation program,
A storage unit 22 that is a storage medium for various processing programs and data, a memory 26 that temporarily holds the programs and data, and the like are provided.

The CAD data 5 is C which is a computer.
It is three-dimensional graphic data input / generated by the AD input device 3, and is also design data that is a basis for manufacturing the three-dimensional model 2 as indicated by an arrow t in FIG. That is,
The three-dimensional model 2 is manufactured by the CAD data 5. The format of the CAD data 5 is IGES (Init
ial Graphics Exchange Specification) is mainly used, but is not limited to this. And CAD
The data 5 is the flow of the arrow u in FIG.
Sent to the CAD data processing device 1 and stored in the storage unit 22. The CAD data 5 indicated by the arrow u may be delivered by a storage medium such as a flexible disk or MO (magneto-optical disk), or the CAD input device 3 and the CAD.
The data processing device 1 may be connected by a cable and communication may be performed by a serial method or a parallel method.

The point cloud data 15 is obtained by scanning the three-dimensional model 2 with a three-dimensional scanner 23 using a laser or the like connected to the point cloud data input device 4 which is a computer, and using the information as a set of point position coordinates. It is data. Although the non-contact type three-dimensional scanner 23 is used in the present embodiment, a contact type measuring device may be used to acquire the point cloud data 15 in the present invention. IGES is mainly used as the format of the point cloud data 15, but the format is not limited to this. And point cloud data 1
5 is sent from the point cloud data input device 4 to the CAD data processing device 1 and stored in the storage unit 22 in the flow of arrow v in FIG. The point cloud data 15 indicated by the arrow v may be delivered by a storage medium such as a flexible disk or MO, or the point cloud data input device 4 and the CAD data processing device 1 may be used.
And may be connected by a cable, and communication may be performed by a serial method or a parallel method.

A design procedure using the CAD data processing apparatus 1 of this embodiment will be described below. This design procedure is performed in the order of FIG. First, a product is designed using the CAD input device 3 (S1). Next, the three-dimensional model 2 of the product is created from the CAD data 5 of the product obtained by the design (S2). The three-dimensional model 2 is created by using a well-known photo-curable resin that has fluidity and is hardened by a laser beam, and a method of sequentially laminating the hardened layers at each height position, for example, a free liquid level method or a ready-made liquid. The surface method is preferred.

Next, the characteristics of the created three-dimensional model 2 are tested (S3), and the results are analyzed to determine whether manual shape correction is necessary (S4). This characteristic includes not only performance but also appearance.
If correction is required, the surface of 3D model 2 (working surface)
The shape is manually corrected by cutting or applying putty material (S5). These steps S3 to S5 are repeatedly executed until it is determined by the test that the shape correction is unnecessary.

If the shape correction is unnecessary, that is, if the characteristics of the stereo model 2 are satisfied, then the shape of the stereo model 2 is measured by the three-dimensional scanner 23 (S6), and the point cloud data is obtained. Input to the input device 4. As a result, the point cloud data 15 that is the position data of the measurement point cloud for the stereo model 2 is acquired.

Next, the CAD data 5 is corrected using the point cloud data 15 thus obtained (S
7). The correction of the CAD data 5 is performed by the process of FIG. 4 described later.

New CAD data 3 obtained by correction
Since No. 5 reflects the information of the point cloud data 15, its correction should basically be unnecessary. Therefore, in the present embodiment, a new three-dimensional model (not shown) is created according to the new CAD data 35 (S8), and the confirmation test (S9) is performed to complete the entire process.

The correction process of the CAD data 5 performed in step S7 will be described below with reference to FIG. The correction processing of the CAD data 5 is performed by the CAD data processing device 1
Executed in.

First, the CAD data 5 sent from the CAD input device 3 and the point cloud data 15 sent from the point cloud data input device 4 are read from the storage unit 22 into the memory 26 (S11).

Next, the reference plane is designated (S1).
2). The instruction of the reference plane is a pre-process for aligning the CAD data 5 and the point cloud data 15 as a whole, and the operator displays a character message of an input request on the display device 24 of the CAD data processing device 1. According to CAD
It is executed by instructing and inputting the three surfaces in the data 5 and the three areas in the surface corresponding to these in the point cloud data 15 as reference surfaces for alignment.

For example, when the operator designates the reference planes 6, 7, 8 (see FIG. 1) in the CAD data 5, the operator designates and inputs the CAD data 5 to that effect and, as shown in FIG. As shown in the point cloud data 15,
An arbitrary number of points in the area included in each surface considered to correspond to the reference surfaces 6, 7, and 8 in the CAD data 5 are selectively input as the reference point groups 16, 17, and 18. This selection input is performed by clicking and dragging on the display screen using the input device 25 (for example, a mouse input device). By these designated input and selection input,
A data file in a table format in which the reference plane 6 and the reference point group 16, the reference plane 7 and the reference point group 17, and the reference plane 8 and the reference point group 18 are individually associated with each other is generated.

Next, the entire alignment of the CAD data 5 and the point cloud data 15 is performed (S13). This overall alignment is performed by subjecting the entire point cloud data 15 to coordinate conversion such that the distance between the corresponding reference planes and the reference point cloud is minimized. Positions of the plurality of points and the reference plane 6, the plurality of arbitrary points included in the reference point group 17 and the reference plane 7, and the plurality of arbitrary points included in the reference point group 18 and the reference plane 8. It is preferable to find a common coordinate transformation matrix that minimizes the sum of squared error of coordinates and to perform coordinate transformation for all points of the point group data 15 using the obtained coordinate transformation matrix.

In steps S14 to S18, CAD
The fitting of the data 5 to the point cloud data 15 is performed. This fitting is a process of moving and transforming each of the plurality of unit shape elements included in the CAD data 5 by changing the parameters thereof so as to match the shape of the point cloud data 15. Here, the unit shape element is a mathematically defined geometric surface such as a plane, a rotation surface, a cylindrical surface, a conical surface, an ellipsoid, a hyperboloid, or a paraboloid, and a Coons patch, B
Free-form surfaces such as esier patches and B-spline patches are included.

First, the unit shape element data contained in the CAD data 5 is individually read (S14). next,
Points near the unit shape element are extracted from the point cloud data 15 (S15). This extraction is executed by selecting all the points in the point group data 15 within the predetermined distance from the unit shape element. As shown in FIG. 6A, the point cloud data 15 at this stage does not match the CAD data 5, and the unit shape elements are different from each other in shape and orientation. It should be noted that although the processing in this embodiment is executed three-dimensionally, the processing shown in FIGS.
For easy understanding, this is shown in two dimensions.

Next, the distances between the plurality of points on the CAD data 5 of the unit shape element and the plurality of points on the extracted point group data 15 are calculated (S16). This distance is calculated, for example, between a plurality of points selected on the point cloud data 15 and the closest point on the CAD data 5 for each of the plurality of points.

Next, the parameters of the CAD data 5 of the unit shape element are changed so that the total distance is minimized (S17). Here, in the CAD data 5 of the unit shape element, it is the position (parallel movement and rotation movement) parameter and the shape parameter that are changed, and the basic attribute indicating the type (for example, plane, cylindrical surface) of the unit shape element. Is not changed. For example, when the unit shape element is a cylinder, the position and direction of the central axis, the radius, and the axial length can be changed, but the attribute itself of the cylinder is not changed.
Similarly, when the unit shape element is a free-form surface, the position coordinates or relative position of each control point can be changed, but the free-form surface (for example, B-spline patch) attribute itself is not changed.

The processing of these steps S15 to S17 is repeatedly executed until the processing is completed for all the unit shape elements in the CAD data 5 (S18). When the fitting is completed in this way, the unit shape element of the CAD data 5 is the point cloud data 15 as shown in FIG. 6B.
The shape and position of the above-mentioned ones are almost the same. Note that here, the CAD data 5 and the point cloud data 15
Although they are almost overlapped with each other, in FIGS. 6B to 6D, for easy understanding, the both are slightly shifted and displayed.

By the way, in the processing up to this point, the CAD data 5 and the point cloud data 15 are almost matched in the comparison between the unit shape elements, but the unit shape elements within the CAD data 5 are matched. Because it is not
In the CAD data 5 at this stage, as shown in FIG. 6B, there may be a gap 36 between the unit shape elements. Therefore, in this embodiment, the gap is corrected in steps S19 to S24.

First, the original CAD data 5 and the new CAD
By comparing with the data 35, for example, comparing the number of edges, a new gap 36 that does not exist in the original CAD data 5 is newly created by the new C.
Whether the AD data 35 has occurred is detected (S1
9) If the gap 36 is generated (S20), then the ends of the pair of (2 sets) unit shape elements sandwiching the gap 36 are respectively extended 37 (FIG. 6C), An intersection line 38 between the two is calculated (S21). The length of the extension 37 may be a predetermined constant value, or may be a value obtained by adding or multiplying the dimension of the gap 36 with a predetermined margin value. The process of step S21 is performed for all the detected gaps 36.
Is repeatedly executed until the processing of (S22) is completed.

Next, all the portions of the new CAD data 35 on the front side of the intersection line 38 are extracted, for example, by detecting all the free ends in the unit shape element, and removed as surplus portions (S23). As a result, one of the gaps 36 shown in FIG. 6D is corrected, and the pair of unit shape elements sandwiching the gap 36 in the new CAD data 35 are connected to each other. Further, by the processing of this step S23, the intersection portion that has occurred in the new CAD data 35 (the portion that is ahead of the intersection line in the unit shape element and has occurred without the processing of step S21)
Is also removed.

When the parameter correction is completed in this way, the processed new CAD data 35 is stored in the storage unit 22 (S24), and this routine ends.

As described above, in the present embodiment, the point cloud data 15 corresponding to each of the plurality of unit shape elements included in the CAD data 5 is extracted (S15), and the position of the extracted measurement point cloud is located within a predetermined range. The parameters of the unit shape element in the CAD data 5 are corrected so as to be compatible within (S17). As a result, in the present embodiment, CA
Since the parameters of the plurality of unit shape elements in the D data 5 are corrected based on the measurement result of the three-dimensional model 2, the accurate new CAD data 3 corresponding to the three-dimensional model 2 is obtained.
You can get 5.

In this embodiment, the new CA is used without changing the attribute indicating the type of the unit shape element in the fitting.
Since it is used as it is in the D data 35, the characteristics according to the type of the unit shape element, such as flatness and roundness, can be retained before and after fitting.

In this embodiment, the CAD data 5 and the point cloud data 15 are aligned (S1).
3), extracting the measurement point group within a predetermined distance from the shape element of the CAD data from the measurement point group after the alignment (S15)
Therefore, the extraction of the measurement point group can be facilitated by this.

Further, in the present embodiment, the unit shape element parameters are corrected so that the total distance between the extracted point group data 15 and the unit shape element in the CAD data 5 is minimized (S17). ), Which is an accurate new CA
The D data 35 can be acquired.

Further, in this embodiment, the gap 36 between the plurality of unit shape elements generated by the correction is detected, and the detected gap is corrected (S21 and S22).
This is preferable because the detection and correction of the gap 36 can be automatically performed. Further, in the present embodiment, after extending the end portions of the unit shape elements that sandwich the gap 36, all the portions on the front side of the intersection line are removed as surplus portions (S23). In addition to the surplus portion that has occurred, the surplus portion that has been generated without depending on the extension of the end portion (especially, the new CAD data 35
It is preferable that the crossing part) that occurs at the end can be removed collectively, but instead of such a configuration, the surplus part generated without the extension of the end part is replaced with the surplus part caused by the extension of the end part. May be separately detected and removed.

Further, in the present embodiment, the correct new CAD data 35 can be acquired by performing the correction process on the CAD data 5 used for creating the three-dimensional model 2, so that the CAD data adapted to the three-dimensional model 2 is newly added. It is not necessary to create it, and the number of steps can be suppressed.

Further, the computer program for executing various processes in the present embodiment is configured as package software for causing the computer to execute the above steps, and is stored in a storage medium or is traded online. Therefore, the intended effect of the present invention can be obtained.

In step S17 of the above embodiment, the total distance between the plurality of points on the CAD data 5 of the unit shape element and the plurality of points on the extracted point group data 15 is set to the minimum. Although the parameter of the CAD data 5 of the unit shape element is changed, the correction process in the present invention may change the parameter so that the distance falls within a predetermined range from the minimum value.

Also, the method of the overall alignment (S13) in this embodiment is merely an example, and instead of another method, for example, designation of a reference plane or selection of a reference point group by the operator,
A method of automatically performing these by predetermined image processing may be used. Further, in the present embodiment, the measurement of the three-dimensional model 2 is performed without contact, but it is also possible to perform this with a contact type three-dimensional measurement device.

Further, in the present embodiment, the CAD data 5 used for creating the stereo model 2 is subjected to the correction processing, but in addition to the case where the stereo model 2 is created by the CAD data 5, the outline of the stereo model 2 is also provided. According to typical dimensions
The present invention can be applied to the case where the D data 5 is manually created in advance. In this case, since the dimensions of each part may be schematic when creating the CAD data 5, if the original CAD data does not exist, for example, in the case of reverse engineering, the labor of creating the CAD data 5 can be reduced. .

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a block diagram showing a CAD data processing device.

FIG. 3 is a flowchart showing a design procedure using the embodiment of the present invention.

FIG. 4 is a flowchart showing a process related to CAD data correction.

FIG. 5 is a perspective view showing point cloud data.

FIG. 6A to FIG. 6D are explanatory views schematically showing a state of CAD data correction and gap correction.

[Explanation of symbols]

1 CAD data processing device, 2 three-dimensional model, 3 CA
D input device, 4 point group data input device, 5 CAD data, 6,7,8 reference plane, 15 point group data, 16,1
7, 18 Reference point group, 22 Storage unit, 23 Three-dimensional scanner, 35 New CAD data, 36 Gap.

Claims (7)

[Claims] 1. A CAD data storage unit for storing CAD data of a stereo model composed of a plurality of shape elements, and position data of a measurement point group obtained by measuring the stereo model corresponding to the CAD data. A measurement data storage unit to store, an extraction unit that extracts the measurement point group corresponding to each of a plurality of shape elements included in the CAD data, and a position of the measurement point group extracted by the extraction unit within a predetermined range. And a correction processing unit that corrects the parameter of the shape element in the CAD data so that 2. The CAD data processing device according to claim 1, wherein the extraction unit includes a position alignment unit that aligns the CAD data with the position data of the measurement point group,
A CAD data processing device, wherein a measurement point group within a predetermined distance from a shape element of the CAD data is extracted from the measurement point group after alignment. 3. The CAD data processing device according to claim 1, wherein the correction processing means sets a total distance between the extracted measurement point group and the shape element from a minimum value to a predetermined value. C, characterized in that the above parameters are corrected to fall within the range
AD data processing device. 4. C according to any one of claims 1 to 3.
A CAD data processing device comprising: an AD data processing device; gap detection means for detecting a gap between the plurality of shape elements generated by the correction; and correction processing means for correcting the detected gap. . 5. The CAD based on CAD data of a three-dimensional model composed of a plurality of shape elements and position data of a measurement point group obtained by measuring the three-dimensional model corresponding to the CAD data. An extraction step of extracting a measurement point group corresponding to each of a plurality of shape elements included in the data, and a parameter of the shape element in the CAD data so as to match the position of the extracted measurement point group within a predetermined range. A CAD data processing method including: a correction processing step of correcting. 6. The CAD data processing method according to claim 5, wherein the three-dimensional model is created based on the CAD data. 7. The CAD based on CAD data of a three-dimensional model composed of a plurality of shape elements and position data of a measurement point group obtained by measuring the three-dimensional model corresponding to the CAD data. An extraction step of extracting a measurement point group corresponding to each of a plurality of shape elements included in the data, and a parameter of the shape element in the CAD data so as to match the position of the extracted measurement point group within a predetermined range. A program that causes a computer to execute the correction processing steps for correction.