JPH04114282A - Three-dimensional solid modeling device - Google Patents

Abstract

PURPOSE:To efficiently prepare a three-dimensional model by providing a means to prepare the cutting plane information of a space, where a real body exists, expressed by a two-dimensional drawing and an extracting means to extract three-dimensional geometrical phase information. CONSTITUTION:The instruction of a processing is inputted from an input device 13, and at a topology/geometry information extraction part 20, the topology data and the geometry data of faces constituting a three-dimensional solid expressed by the drawing are generated based on a two-dimensional drawing data and respectively stored in storage parts 21 and 22. Next, an edge trace/ solid model preparation part 23 executes a processing to generate the three- dimensional solid model according to the topology data and the geometry data of the faces. Then, the three-dimensional solid model generated by the processing like this is stored in an external storage device 15 and the result is displayed by a display device 12. Thus, the processing of the three-dimensional model from the two-dimensional drawing can be efficiently realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a three-dimensional solid modeling device that generates a three-dimensional model from a two-dimensional drawing.

[Prior Art] The following method is known as a method for generating a three-dimensional solid model from a two-dimensional drawing.

°H,5akurai and D,C,Gossar
d.”5solid modelnput through
h orthographic view”, ACM
Computer Graphics, Vol. 17. N
O, 3, July 1985. pp, 243-252
In this method, a three-dimensional wire frame model is first created from a two-dimensional three-dimensional view, and a solid model is created based on this.

・gasamy to V, N and N, A, Lan
grana, Reconstructjon of 3
D objects using a kd env
ironmenbi.

ASME Computers 1n Engineer
ring 1989. Vol, 1゜July 1989
．． pp, 117-126 A method of extracting the basic solids that make up a solid from a drawing and combining these basic solids to generate a solid model [Problem to be solved by the invention] When considering the form of use of CAD in the product development process In design, it is desirable to use two-dimensional drawings that are easy to manipulate and express, and in subsequent processes to use three-dimensional models that can accurately represent the product shape. For that purpose 2
Requires conversion from dimensional drawings to more sophisticated solid models.

However, at present, no method has been established for converting a two-dimensional drawing into a solid model on a practical level.

In the method using wireframes, which is represented by the first known example mentioned above, (1) - Unnecessary edges are generated in the process of generating a 3D wireframe model, and it is difficult to remove them. Work is required.

(2) There are many restrictions and conditions when converting a wire frame model to a solid model.

(3) Creating solid candidate models for all possible combinations of shapes from the wireframe model requires a very high calculation load, and in some cases it is necessary to select the one that can be established as a solid model from among the candidates. Create multiple models.

(4) It has the disadvantage of not allowing drawing errors or calculation errors.

The method mentioned in the following known example is also effective for simple drawings, but (5) Since pattern matching is basically performed using a knife, it cannot be used when the shape becomes complex. It becomes possible.

(6) If the drawing contains minute errors, runaway calculations are likely to occur.

It has the disadvantage of

The present invention overcomes these drawbacks and provides a practical two-dimensional/
Achieve 3D conversion.

[Means for Solving the Problems] The present invention provides three-dimensional information, including means for creating cutting plane information of an entity existence space expressed in a two-dimensional drawing, and extraction means for extracting three-dimensional geometric topology information. Create a model.

In addition, as a means to create a 3D model from a 2D drawing, the 2D drawing is once converted to 25 dimensions, and from the cut surface shape of the 3D created while recognizing the entity existence space expressed in the 2.5D drawing. , extract connection information between surfaces that make up a 3D solid, and the features of the surfaces themselves, that is, surface and topology information, and geometry information, and use these two pieces of information to create a 3D object completely independently of the 2D drawing. It creates a solid model.

According to the present invention, the topology information and geometry information of the surface extracted from the two-dimensional drawing are first determined, and then the edges are calculated for generating the three-dimensional solid model, so even if the shape is complex, The calculation load is light, and it is possible to stably convert a 2D drawing to a 3D solid model without running out of control or outputting multiple warm shapes due to calculation errors.It also avoids inconsistencies and errors in the future. Even when dealing with different drawings, it is possible to respond flexibly by interactively making corrections to the obtained topology and geometry information.

[Embodiment] FIG. 1 is a block diagram illustrating one embodiment of the present invention. In the figure, 1o is a processing device, in which a processing program having the procedure shown in FIG. , 11 is realized. Reference numeral 12 denotes a display device for displaying a model of a processing result, a manual drawing, or a drawing in progress. Reference numeral 13 denotes a human-powered device that manually inputs editing, modification, position and correction commands and messages that give instructions to the processing device using keys, a cursor, or an icon. 14 is 2 as input data to be processed
It is a storage device that stores dimensional CAD diagrams. 1
5 is an external storage device that outputs a three-dimensional solid model as a processing result. 16 is a network interface for communicating with an external system. Further, within the modeling system 11, 20 is a topology information/geometry information extraction section. 21 is a storage unit that stores topology data of the extracted surface. 22 is a storage unit that stores surface geometry data.
23 is an edge trace/solid model creation section.

The processing of the present invention will be explained using the descriptive structure with reference to the drawings.

First, two-dimensional CAD drawing data is loaded from the external storage device 14 into the memory in the processing device 10 according to an instruction from the human-powered device 13 .

Next, the processing instructions are given manually according to instructions from the human-powered device 13, and first, the topology information/geometry information extraction unit 2
0, based on the two-dimensional drawing data, topology data and geometry data of surfaces constituting the three-dimensional solid represented by the drawing are generated and stored in the storage unit 21.2.
2. When such processing is completed, the edge trace/solid model creation section 23 performs processing to create a three-dimensional solid model from the surface topology data and geometry data. The three-dimensional solid model generated through such processing is stored in the external storage device 15. Such results are also displayed by display device 12.

Next, detailed processing in each of the above-mentioned processing units will be explained for each processing unit.

First, regarding the topology information/geometry information extraction unit 20 shown in FIG.
In the step, the drawing is converted to 25 dimensions, the second step is to set the cutting level, the third step is to create the cutting plane, and the fourth step is to set the cutting level.
In the step, topology scanning is performed, and in the fifth step, surface topology and geometry data creation are performed.

Step] Converting the drawing to 25 dimensions, that is, adding the shape (surface shape) in the height direction of the region to the closed region on the two-dimensional drawing as shown in Fig. 3a. Create 2.5-dimensional surface data as shown in .

1) Define the surface shape for areas where information in the height direction can be uniquely recognized from the correspondence on the drawing.

2) Similarly, holes are defined in areas that are clearly found to be holes from the correspondence on the drawing.

3) For areas that cannot be automatically recognized, the surface shape is instructed in an operation.

Step 2. Setting the cutting level This device determines the geometric phase of the entire shape by reading changes in the geometric phase of the theoretical cross section in each of the x, y, and z directions.

To do this, we must not overlook even the smallest changes in each direction, and set a cutting level that picks up all the points where changes in the geometric topology can occur and cuts the section between them (shape feature section). Let's do it.

Step 3 Creation of cutting planes Based on the 2.5-dimensional data, create cutting plane shapes in the shape feature sections in each of the x, y, and z directions, as shown in FIG. 4, without being aware of the space in which the entity exists. Regarding the creation of such a cut plane - There is no entity on the near side (= line of sight direction) of the plane defined as an entity on the 2.5-dimensional drawing.

・At the back of the area defined as an entity on a 2.5-dimensional drawing, there is a semi-infinite space where entities are scattered (= entity existence space)
There is.

・No entity exists on the front or back side of the area defined as a hole on the 2.5-dimensional drawing.

・The three-dimensional space actually represented by the drawing is determined by each VIE on the drawing.
It is expressed in the form of a logical product of the entity existence space claimed by W (~surface diagram).

Taking the above points into consideration, the process is performed as follows.

1) Set the cutting plane.

2) Create a semi-infinite (actually finite) cutting shape within the cutting plane that expresses the semi-infinite entity existence space claimed by each VIEW.

3) Obtain the three-dimensional cut surface shape by taking the AND of the semi-infinite cut shapes of each VIEW.

Step 4: Topology scan The cut plane shape is scanned in each of the X, Y, and Z directions as shown in FIG. 5 to recognize changes in phase between adjacent surfaces and to accumulate surface connection information. In other words, processing is performed taking the following points into consideration.

- By creating a cut plane in small increments in each of the X, Y, and Z directions and scanning it, you can recognize changes in the connection relationships between the surfaces that make up the cut plane.

- If a combination of surfaces that did not exist at the previous cutting level appears when compared in the scanning direction, this is recognized as connection information between surfaces that constitute a solid.

- The actual cutting area is the section between the shape feature points in each of the X, Y, and Z directions on the drawing (=shape feature section).

Taking the above points into consideration, the process is performed as follows.

1) Add surface attribute information to each element of the cut surface shape.

2) Scan in each of the X, Y, and Z directions to recognize changes in the phase of the cut plane before and after the scanning direction, and add connection information between the cut plane elements where there is a change to each element of the cut plane. This is stored as surface-to-surface joint information, which is attribute information.

Step 5 Generation of surface topology/geometry data 1) Organize the connection information of each surface on a surface-by-surface basis and stock it as surface connection information.

2) Generate surfaces and geometry pigs from the type and shape of each surface.

Next, details of the edge trace/solid model creation section 23 shown in FIG. 1 will be explained.

First, a graph search is performed based on the connection information of the recognized surfaces. Performs loop ranking of adjacent surfaces. Edges are calculated from the surfaces for which the adjacency relationship has been determined, and a B-reps type solid model having a winged-edge structure is created. In other words, the connection information (topology) of the surfaces extracted from the drawing by topology scanning and the surface shape (geometry) of the surfaces.
The edge of the surface is determined based on this information.

・Use a graph search method to divide adjacent surfaces into loops and determine the arrangement of adjacent surfaces.

・Calculate the intersection lines between the surfaces whose adjacency relationship has been determined to determine the edges.

Taking the above points into consideration, the following processing steps are performed.

1) Receive surface topology data (l!a tangent surface information, unevenness information) and geometry data (surface shape information).

2) Using graph search based on adjacent surface information, divide surfaces into loops and determine the order of adjacent surfaces within the loop.

3) In accordance with the determined order of loops, intersection lines between adjacent surfaces are calculated in order to create edges.

4) Generate solid model data from the created edge information.

By processing as described above, it is possible to efficiently process a three-dimensional model from a two-dimensional drawing.

[Effects] According to the present invention, by providing means for creating section information of the entity existence space expressed by a two-dimensional drawing and extraction means for extracting three-dimensional geometric topology information, three-dimensional It is possible to create a dimensional model.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining the present invention in detail. FIG. 2 is a diagram showing a processing procedure for explaining an embodiment of the present invention. FIG. 3 a is information processed by the embodiment of the present invention. FIG. 3 is a diagram showing an example of information processed by an embodiment of the present invention FIG. 4 is a diagram showing an example of information processed by an embodiment of the present invention FIG. 5 is a diagram showing an example of information processed by an embodiment of the present invention FIG. 20 shows an example of information processed by the embodiment of FIG. Pv Rν

Claims (1)

[Scope of Claims] 3, comprising: means for creating cutting plane information of an entity existence space expressed in a two-dimensional drawing; and extraction means for extracting three-dimensional geometric topology information.
dimensional solid modeling equipment