Method and system for extracting central axis and shape of pipe

Abstract

The invention provides a method and a system for extracting a central axis and a shape of a pipe. The system comprises a file import module which receives and processes a workpiece drawing in a 3D format uploaded by a user; the data analysis module analyzes the imported workpiece drawing in the 3D format; the central axis segment extraction module identifies and extracts a central axis segment related to the pipe; the central axis construction module processes the extracted central axis segment; the shape data extraction module defines a data structure of a pipe shape and converts the constructed central axis into the data structure for representation; the graph display module is used for displaying an original 3D workpiece drawing and a processed graph only containing a pipe part; and the output module outputs the processed central axis shape data in a format suitable for subsequent processing. According to the method, direct importing of the 3D format file is supported, a new algorithm and technology are introduced, so that the pipe forming system can directly read and process the 3D CAD file, and the step of converting a 3D model into a 2D drawing is omitted.

Description

Technical Field

[0001] The invention relates to the technical field of pipe processing and forming, and in particular to a method and system for extracting the central axis and shape of a pipe. Background Art

[0002] Tube forming is an important branch of metal processing, which is widely used in industries such as construction, furniture, automobiles, aerospace, and machinery manufacturing. With the development of industry technology, especially the popularization of computer-aided design (CAD) and computer-aided manufacturing (CAM) systems, the accuracy and efficiency of tube forming processing have been significantly improved. In modern industrial production, CAD files are widely used in the design and planning stages, and these files usually contain detailed three-dimensional (3D) information.

[0003] Deficiencies of existing technology: 1. Does not support 3D format file import: Currently, the tube forming systems on the market can generally only process 2D DXF drawings, and do not support direct import of 3D CAD files. This means that users must first convert the original 3D workpiece drawings into 2D format, which adds extra workload.

[0004] 2. Manually draw 2D drawings: In order to use the CAD file import function of the tube forming system, users need to manually draw a 2D DXF drawing containing only the tube shape information based on the original 3D workpiece drawing through software such as AutoCAD or SolidWorks; this is not only time-consuming and labor-intensive, but also prone to human errors.

[0005] 3. Strict requirements for drawings: The drawn 2D drawings must meet specific format requirements, such as the central axis must be continuous and cannot have any redundant parts; such requirements make drawing preparation more complicated and increase the possibility of errors.

[0006] 4. Lack of automated processing: Existing methods cannot automatically identify and discard non-pipe parts in 3D drawings, requiring users to manually delete these irrelevant parts, a process that also consumes time and effort.

[0007] 5. Difficult verification: Due to the lack of intuitive preview function, it is difficult for users to accurately judge whether the parsed 2D drawings correctly reflect the intention of the original 3D model before actual processing, which may lead to unnecessary rework and waste.

[0008] Therefore, the prior art has deficiencies and needs further improvement. Summary of the invention

[0009] In view of the problems existing in the prior art, the present invention provides a method and system for extracting the central axis and shape of a pipe.

[0010] To achieve the above object, the specific scheme of the present invention is as follows: The present invention provides a pipe centerline and shape extraction system, the system comprising: File import module: used to receive and process 3D workpiece drawings uploaded by users; Data parsing module: uses the Open CASCADE Technology (OCCT) library to parse the imported 3D workpiece drawings and extract geometric information; Centerline segment extraction module: identifies and extracts centerline segments related to pipes, while removing duplicate centerline segments and non-pipe parts; Central axis construction module: processes the extracted central axis segments, ensures the consistency of direction, connects the segments connected at the beginning and end, and merges the continuous straight line segments or arc segments with the same direction; Shape data extraction module: defines the data structure of the tube shape and converts the constructed centerline into the data structure representation. The parameters include length, arc, radius, and turning angle. Graphics display module: provides a graphical interface for displaying the original 3D workpiece drawing and the processed graphics containing only the pipe part, so that users can verify the analysis results; User interaction module: allows users to adjust parameters through a graphical interface, including selecting the processing starting point of a closed figure; Output module: Output the processed central axis shape data in a format suitable for subsequent processing, including generating 2D DXF files or other required formats.

[0011] Furthermore, the file import module supports multiple 3D file formats, including STEP, IGES, and STL.

[0012] Furthermore, the data parsing module can automatically detect and repair geometric errors in the Step file to improve parsing accuracy.

[0013] Furthermore, the central axis segment extraction module also includes a filter for eliminating non-pipe related parts, including bolts and beams, and only retaining the central axis segment related to the pipe.

[0014] Furthermore, the graphic display module also provides a comparison view function, which simultaneously displays the original 3D workpiece drawing and the processed graphic containing only the pipe part, so as to facilitate intuitive comparison by the user.

[0015] The present invention also provides a method for extracting the central axis and shape of a pipe. Based on the above extraction system, the method comprises the following steps: S1, drawing file import: receiving the workpiece drawing in 3D format uploaded by the user; S2, drawing file data parsing: using the Open CASCADE Technology (OCCT) library to read and parse the geometric information in the drawing file; S3, extraction of pipe centerline segments: Identify and extract the centerline segments related to the pipe, and remove duplicate centerline segments and non-pipe parts; S4, central axis construction: process the extracted central axis segments, ensure the consistency of direction, connect the end-to-end segments, and merge the continuous and consistent straight line segments or arc segments; S5, center axis shape data extraction: define the data structure of the tube shape, and convert the constructed center axis into the data structure representation, the parameters include length, arc, radius, and turning angle; S6, Graphics display: Display the original 3D workpiece drawing and the processed graphics containing only the pipe part on the user interface for the user to verify the analysis results; S7, user interaction: allows the user to adjust parameters through the graphical interface, including selecting the processing starting point of the closed figure; S8, data output: output the processed central axis shape data in a format suitable for subsequent processing, including generating a 2D DXF file or other required format.

[0016] Furthermore, in step 2, the data analysis module also includes a geometric error detection and repair function to ensure the accuracy of the analysis results.

[0017] Furthermore, in step 3, the extraction of the central axis segment of the pipe also includes automatic identification and elimination of non-pipe components to simplify the processing process.

[0018] Furthermore, in step 4, the central axis construction also includes checking and correcting the direction consistency of the central axis segments to ensure that all line segments have consistent directions.

[0019] Furthermore, in step 6, the graphic display also includes a comparison view function, which simultaneously displays the original 3D model and the processed 2D graphics to facilitate intuitive comparison by the user.

[0020] The technical solution of the present invention has the following beneficial effects: 1. Support direct import of 3D format files: By introducing new algorithms and technologies, the tube forming system can directly read and process 3D CAD files, eliminating the step of converting 3D models into 2D drawings and simplifying the workflow.

[0021] 2. Reduce manual intervention and errors: Automatically extract necessary pipe information from 3D models and automatically generate 2D drawings suitable for pipe forming processing, which reduces the requirements for users' manual drawing skills and reduces errors caused by human factors.

[0022] 3. Improve work efficiency: Since there is no need to draw or modify drawings manually, the entire preparation process becomes more efficient, saving a lot of time and cost, and speeding up the product's time to market.

[0023] 4. Enhanced design flexibility: Allowing designers to create more freely in a 3D environment without having to worry about technical limitations in the subsequent manufacturing stage, thus promoting the development of innovative designs.

[0024] 5. Improve drawing quality and consistency: Automated data processing ensures that the generated 2D drawings meet the specific requirements of the tube forming system, improves the consistency and accuracy of the drawings, and ensures the quality of the final product.

[0025] 6. Provide intuitive preview function: The new system can display the relationship between the parsed 2D drawing and the original 3D model, allowing users to confirm whether the design intent is accurately implemented before actual processing, further reducing the error rate.

[0026] 7. Optimize material utilization: By effectively identifying and eliminating non-pipe parts in the 3D model, unnecessary material waste is avoided, which helps to improve overall production efficiency and reduce costs.

[0027] 8. Promote cross-platform collaboration: Support a variety of popular 3D modeling software output formats, enhancing communication and cooperation capabilities between different departments and upstream and downstream of the supply chain. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a display diagram after the Step file of the embodiment of the present invention is imported; Figure 2 This is a diagram showing the shape of the central axis of an embodiment of the present invention; Figure 3 is a logic flow chart of central axis extraction of an embodiment of the present invention; Figure 4 It is the overall flow chart of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments; it can be understood that the specific embodiments described herein are only used to explain the present invention rather than to limit the present invention; it should also be noted that, for ease of description, only the parts related to the present invention rather than all are shown in the accompanying drawings.

[0030] Combination Figure 1-Figure 4 As shown, the present invention provides a system for extracting the central axis and shape of a pipe, the system comprising: File import module: used to receive and process 3D workpiece drawings uploaded by users; Data parsing module: uses the Open CASCADE Technology (OCCT) library to parse the imported 3D workpiece drawings and extract geometric information; Centerline segment extraction module: identifies and extracts centerline segments related to pipes, while removing duplicate centerline segments and non-pipe parts; Central axis construction module: processes the extracted central axis segments, ensures the consistency of direction, connects the segments connected at the beginning and end, and merges the continuous straight line segments or arc segments with the same direction; Shape data extraction module: defines the data structure of the tube shape and converts the constructed centerline into the data structure representation. The parameters include length, arc, radius, and turning angle. Graphics display module: provides a graphical interface for displaying the original 3D workpiece drawing and the processed graphics containing only the pipe part, so that users can verify the analysis results; User interaction module: allows users to adjust parameters through a graphical interface, including selecting the processing starting point of a closed figure; Output module: Output the processed central axis shape data in a format suitable for subsequent processing, including generating 2D DXF files or other required formats.

[0031] The file import module supports multiple 3D file formats, including STEP, IGES, and STL.

[0032] The data parsing module can automatically detect and repair geometric errors in the Step file to improve parsing accuracy.

[0033] The central axis segment extraction module also includes a filter for eliminating non-pipe related parts, including bolts and beams, and only retaining the central axis segment related to the pipe.

[0034] The graphic display module also provides a comparison view function, which simultaneously displays the original 3D workpiece drawing and the processed graphic containing only the pipe part, so that the user can make an intuitive comparison.

[0035] The present invention also provides a method for extracting the central axis and shape of a pipe. Based on the above extraction system, the method comprises the following steps: S1, drawing file import: receiving the workpiece drawing in 3D format uploaded by the user; S2, drawing file data parsing: using the Open CASCADE Technology (OCCT) library to read and parse the geometric information in the drawing file; S3, extraction of pipe centerline segments: Identify and extract the centerline segments related to the pipe, and remove duplicate centerline segments and non-pipe parts; S4, central axis construction: process the extracted central axis segments, ensure the consistency of direction, connect the end-to-end segments, and merge the continuous and consistent straight line segments or arc segments; S5, center axis shape data extraction: define the data structure of the tube shape, and convert the constructed center axis into the data structure representation, the parameters include length, arc, radius, and turning angle; S6, Graphics display: Display the original 3D workpiece drawing and the processed graphics containing only the pipe part on the user interface for the user to verify the analysis results; S7, user interaction: allows the user to adjust parameters through the graphical interface, including selecting the processing starting point of the closed figure; S8, data output: output the processed central axis shape data in a format suitable for subsequent processing, including generating a 2D DXF file or other required format.

[0036] In step 2, the data analysis module also includes geometric error detection and repair functions to ensure the accuracy of the analysis results.

[0037] In step 3, the extraction of the central axis segment of the pipe also includes automatic identification and elimination of non-pipe parts to simplify the processing process.

[0038] In step 4, the central axis construction also includes checking and correcting the direction consistency of the central axis segments to ensure that all line segments have consistent directions.

[0039] In step 6, the graphic display also includes a comparison view function, which simultaneously displays the original 3D model and the processed 2D graphics to facilitate intuitive comparison by the user.

[0040] Example: Tube forming is an important branch of metal processing, which is widely used in industries such as construction, furniture, automobile, aerospace and machinery manufacturing. With the development of industry technology, especially the popularization of computer-aided design (CAD) and computer-aided manufacturing (CAM) systems, the precision and efficiency of tube forming processing have been significantly improved. However, in the current market, the CAD files used for tube forming are generally two-dimensional (2D) drawings in DXF format, which do not support the import and analysis of 3D files. If users want to use the CAD file import function of the tube forming system, they must first use AutoCAD or Soildworks software to manually draw a two-dimensional, linear (central axis) DXF file drawing containing only the tube shape information based on the original 3D workpiece drawing (the drawn central axis must also be continuous and cannot have any other redundant parts), and then hand this drawing over to the system for analysis, that is, the process is: "get the original 3D workpiece drawing → draw the corresponding 2D workpiece drawing strictly in accordance with the format → import into the tube forming control system".

[0041] The system composition and functional modules of the present invention are as follows: File import module: used to receive and process 3D format (such as STEP) workpiece drawings uploaded by users, and pass the imported 3D files to the data analysis module for further processing.

[0042] Data parsing module: Use the Open CASCADE Technology (OCCT) library to parse the imported 3D model files and extract geometric information.

[0043] Centerline segment extraction module: Identify and extract centerline segments related to pipes, and remove duplicate centerline segments and non-pipe parts.

[0044] Central axis construction module: processes the extracted central axis segments, ensures the consistency of direction, connects the line segments connected at the beginning and end, and merges the continuous and consistent straight line segments or arc segments. After the construction is completed, the final central axis is passed to the shape data extraction module.

[0045] Shape data extraction module: defines the data structure of the tube shape and converts the constructed centerline into the data structure representation, including parameters such as length, radian, radius, and turning angle. Based on the centerline generated by the centerline construction module, extracts relevant shape data and prepares for output or display.

[0046] Graphics display module: provides a graphical interface for displaying the original 3D workpiece drawing and the processed graphics containing only the pipe part, so that users can verify the analysis results.

[0047] User interaction module: allows users to interact with the system through a graphical interface, such as selecting the processing starting point, adjusting parameters, etc.

[0048] Output module: Output the processed centerline shape data in a format suitable for subsequent processing, such as generating a 2D DXF file or other required format.

[0049] The file import module is the entrance to the entire system. It receives the 3D files uploaded by users and passes them to the data parsing module.

[0050] The data parsing module uses the OCCT library to parse the 3D file and passes the parsed geometric information to the central axis segment extraction module.

[0051] The centerline segment extraction module processes and selects the centerline segments related to the pipe, and then passes this information to the centerline construction module.

[0052] The central axis construction module is used to construct a continuous central axis with consistent direction, and pass the result to the shape data extraction module.

[0053] The shape data extraction module converts the central axis into a specific data structure and passes this data to the graphic display module and the output module.

[0054] The graphical display module and the user interaction module together provide an intuitive interface that allows the user to view and verify processing results and adjust parameters as needed.

[0055] The output module will eventually output the processed data to prepare for subsequent tube forming processing.

[0056] Through this modular design, the present invention realizes an automated process from 3D workpiece drawings to pipe centerline and shape extraction, improves efficiency and reduces human errors.

[0057] Working steps: File import: Users upload workpiece drawings in 3D format (such as STEP) to the system.

[0058] File data analysis: Use the Open CASCADE Technology (OCCT) library to read and analyze the geometric information in the Step file. Extract the necessary geometric data from the file imported in the previous step to prepare for the subsequent central axis segment extraction.

[0059] Extraction of the centerline segment of the pipe: Identify and extract centerline segments related to the tube, while removing duplicate centerline segments and components that are not part of the tube.

[0060] Based on the data obtained from the previous analysis, effective central axis segments are screened out to provide a basis for constructing a continuous central axis.

[0061] Central axis construction: Process the extracted central axis segments to ensure directional consistency, connect the end-to-end segments, and merge continuous straight line segments or arc segments with consistent directions.

[0062] The centerline segment extracted in the previous step is received, and a complete and continuous centerline is formed through a series of processing steps to prepare for shape data extraction.

[0063] Central axis shape data extraction: Define the data structure of the tube shape and convert the constructed centerline into the data structure representation, including parameters such as length, arc, radius, and rotation angle.

[0064] Based on the complete central axis constructed in the previous step, the required shape data is extracted, which will be used for the final graphic display and output.

[0065] Graphical display: The original 3D workpiece drawing and the processed drawing containing only the tube part are displayed on the user interface for users to verify the analysis results.

[0066] Combining the original 3D model and the extracted central axis shape data, an intuitive preview is provided to users to help them confirm whether the design intent is accurately realized.

[0067] User Interaction: Allows users to adjust parameters through a graphical interface, such as selecting the processing starting point of a closed shape.

[0068] Users can modify some parameters while viewing the graphic display to meet specific processing requirements. The user's adjustments will be fed back to the corresponding functional modules.

[0069] Data output: The processed centerline shape data is output in a format suitable for subsequent processing, such as generating a 2D DXF file or other required format.

[0070] Based on the final shape data, a file is generated that can be directly used in the tube forming control system to complete the entire workflow.

[0071] The connection between the steps File import is the beginning of the entire process and provides the basic data required for all subsequent steps.

[0072] File data analysis converts 3D models into operable geometric data, laying the foundation for subsequent extraction and construction.

[0073] The two steps of pipe centerline segment extraction and centerline construction are closely related. The former is used to screen out valid centerline segments, while the latter is used to combine these segments into a complete centerline.

[0074] The centerline shape data extraction is based on the constructed centerline and converts it into specific shape parameters, which are crucial for actual processing.

[0075] Graphical displays and user interaction provide a visual platform that allows users to inspect and adjust processing results.

[0076] Data output is the end point of the entire process, which is to output the processed data in a suitable format for actual processing.

[0077] This workflow ensures a seamless transition from 3D models to the data required for machining, improving work efficiency and accuracy.

[0078] Design and develop a software module that can directly parse the user's 3D workpiece drawings, that is, to achieve "get the original 3D workpiece drawings → import into the pipe forming control system", the core part of which is the extraction of the pipe centerline and shape. The present invention provides a method for extracting the pipe centerline and shape, which mainly consists of four parts: 1. Step file data analysis.

[0079] In this part, we use the Open CASCADE Technology (OCCT) library as the support library for step file data parsing. OCCT is a powerful open source CAD kernel and development platform. The specific steps are as follows: a) Import the user's step file. Here we call the "ReadFile" method of the "STEPControl" class in the OCCT library; b) Use the "Extent" and other methods of the "TopTools_IndexedMapOfShape" and other classes in the OCCT library to parse and obtain the information in the step file; c) Display the step file based on the information obtained.

[0080] like Figure 1 , is an example of importing and displaying a step file.

[0081] 2. Extract the centerline section of the pipe.

[0082] a) According to the information of the acquired step file, extract the centerline segment of the pipe element. This step will discard the parts that are not part of the pipe, such as Figure 1The seat cushion and backrest portion of a chair; b) Remove repeated centerline segments. In the previous process, many repeated line segments will be generated, which need to be removed to ensure that each part of the pipe corresponds to only one centerline segment.

[0083] 3. Construction of the central axis.

[0084] a) Direction. Make the directions of all analyzed line segments consistent to ensure that the directions of all central axis segments are consistent; b) Splicing. Connect the segments that can be connected at the beginning and end to form a longer and more complete segment. In this process, there will be some scattered small segments, which may be bolts, beams and other redundant parts, which need to be discarded; c) Merge. Merge two or more consecutive straight line segments into a longer straight line segment, and merge two or more consecutive arcs with the same direction into a longer arc.

[0085] 4. Extraction of central axis shape data.

[0086] a) Define the data format to be extracted. In this invention, we define the shape data structure of the pipe as: length, radian, radius, turning angle; b) Convert the central axis into a defined data structure representation. Start parsing the central axis from the starting point and obtain the parameters of each straight line segment or arc in turn, for example, Figure 1 The pipe shape parameters parsed from the step file are shown in the following table:

[0087] Serial numbers 1 and 11 are the starting points (the starting points need to be determined according to the machine model and processing scenario). This example is an analytical example based on the control system of a double-head pipe bending machine, that is, bending the pipe from both sides.

[0088] c) Finally, the relevant shape data is extracted based on the obtained central axis to show the shape of the product to be processed. Figure 1 The final analyzed pipe shape Figure 2 shown.

[0089] 1. The present invention supports direct import of 3D files, that is, the user does not need to convert the 3D files into 2D files before importing them, thus achieving a breakthrough from 0 to 1.

[0090] 2. The present invention does not require the user to delete components other than pipes in the 3D file, and can automatically identify and discard non-pipe parts, thereby realizing the intelligentization of the CAD import function.

[0091] 3. For closed graphics, the present invention can support users to change the processing starting point.

[0092] 4. The present invention can display both the original workpiece of the step and the graphics containing only the pipe part after analysis, so that the user can know the correctness of the analysis before processing.

[0093] The key of the present invention is: 1. Use Open CASCADE Technology (OCCT) library as the support library for step file parsing.

[0094] 2. Logical steps for extracting the centerline and shape of the pipe.

[0095] 3. It can display both the original workpiece of the step and the graphics containing only the pipe part after parsing.

[0096] The specific numerical values ​​described in the present invention are all examples to illustrate the logic of the present invention, and are not intended to limit the scope of the patent of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly used in the technical field related to tube forming, are also included in the patent protection scope of the present invention.

[0097] like Figure 3 The following is the logic flow chart of central axis extraction: 1. Import Step file: import a Step file into the system; 2. Step file data analysis: Analyze the imported Step file to extract the data, display the step file graphics, and use the OCCT library to parse the step file data; 3. Extraction of centerline segments in pipes: Identify and extract the centerline segments related to the pipe in the Step file; The central axis of the pipe element is proposed, and non-pipe elements and repeated central axis segments of pipe elements are discarded; 3. Construct the central axis: After extracting the center line, the next step is to combine these line segments to form a continuous central axis; Maintain the consistency of the central axis directions of the pipe elements, merge the central axis segments, and splice the central axis segments; 4. Extract the shape data of the central axis: further process the constructed central axis to obtain its geometric features or define its shape data structure; Define the shape data structure, convert the centerline segment of the tube into the defined data structure representation, and display the constructed tube image.

[0098] Working principle: A method and system for extracting the center axis and shape of a pipe is provided, aiming to automatically extract the center axis and shape information of the pipe directly from the 3D workpiece drawing, so as to facilitate the subsequent pipe forming process. The method mainly consists of the following steps: Step file data analysis: Use Open CASCADE Technology (OCCT) library as the technical support for step file data parsing.

[0099] Import the user's step file and use the "ReadFile" method of the "STEPControl" class in the OCCT library to read the file.

[0100] Parse and obtain the geometric information in the step file through methods such as "TopTools_IndexedMapOfShape" in the OCCT library.

[0101] Display the parsed step file graphics for users to review initially.

[0102] Extraction of the centerline segment of the pipe: According to the step file information obtained by parsing, the centerline segment related to the pipe is extracted.

[0103] Discard non-tube parts, such as the seat cushion and backrest.

[0104] Remove duplicate centerline segments and ensure that each section of pipe corresponds to only one centerline segment.

[0105] Central axis construction: All extracted central axis segments are processed for direction consistency to ensure that all line segments have the same direction.

[0106] Connect line segments that can be connected end to end to form longer, more complete line segments.

[0107] Merge continuous straight or circular segments to simplify the centerline structure while removing redundant components such as bolts or beams.

[0108] Central axis shape data extraction: Define the pipe shape data structure, including parameters such as length, arc, radius and turning angle.

[0109] The central axis is parsed from the starting point, and the parameters of each straight line segment or arc are obtained in turn, and converted into the defined data structure representation.

[0110] Extract relevant shape data and display the shape of the product to be processed.

[0111] Workflow summary: Import Step file: Import a 3D model file in Step format into the system.

[0112] Step file data parsing: Use the OCCT library to parse the geometric data in the Step file and display the original model.

[0113] Pipe centerline segment extraction: Identify and extract the centerline portion related to the pipe, and eliminate non-pipe entities and repeated centerline segments.

[0114] Construct the central axis: Combine the extracted central axis segments to form a continuous central axis with consistent direction.

[0115] Extract centerline shape data: Convert the constructed centerline into a specific data structure representation and display the final tube shape.

[0116] Through this series of steps, the present invention realizes the automatic conversion from 3D CAD files to 2D drawings required for tube forming processing, which greatly improves efficiency and accuracy.

[0117] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the protection scope of the present invention.

Claims

1. A pipe centerline and shape extraction system, characterized in that: The system includes: File import module: used to receive and process 3D workpiece drawings uploaded by users; Data parsing module: uses the Open CASCADE Technology library to parse the imported 3D workpiece drawings and extract geometric information; Centerline segment extraction module: identifies and extracts centerline segments related to pipes, while removing duplicate centerline segments and non-pipe parts; Central axis construction module: processes the extracted central axis segments, ensures the consistency of direction, connects the segments connected at the beginning and end, and merges the continuous straight line segments or arc segments with the same direction; Shape data extraction module: defines the data structure of the tube shape and converts the constructed centerline into the data structure representation. The parameters include length, arc, radius, and turning angle. Graphics display module: provides a graphical interface for displaying the original 3D workpiece drawing and the processed graphics containing only the pipe part, so that users can verify the analysis results; User interaction module: allows users to adjust parameters through a graphical interface, including selecting the processing starting point of a closed figure; Output module: Output the processed central axis shape data in a format suitable for subsequent processing, including generating 2DDXF files or other required formats.

2. The pipe centerline and shape extraction system according to claim 1, characterized in that: The file import module supports multiple 3D file formats, including STEP, IGES, and STL.

3. The pipe centerline and shape extraction system according to claim 1, characterized in that: The data parsing module can automatically detect and repair geometric errors in the Step file to improve parsing accuracy.

4. The pipe centerline and shape extraction system according to claim 1, characterized in that: The central axis segment extraction module also includes a filter for eliminating non-pipe related parts, including bolts and beams, and only retaining the central axis segment related to the pipe.

5. The pipe centerline and shape extraction system according to claim 1, characterized in that: The graphic display module also provides a comparison view function, which simultaneously displays the original 3D workpiece drawing and the processed graphic containing only the pipe part, so that the user can make an intuitive comparison.

6. A method for extracting the central axis and shape of a pipe, based on the extraction system according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: S1, drawing file import: receiving the workpiece drawing in 3D format uploaded by the user; S2, drawing file data parsing: using the Open CASCADE Technology library to read and parse the geometric information in the drawing file; S3, extraction of pipe centerline segments: Identify and extract the centerline segments related to the pipe, and remove duplicate centerline segments and non-pipe parts; S4, central axis construction: process the extracted central axis segments, ensure the consistency of direction, connect the end-to-end segments, and merge the continuous and consistent straight line segments or arc segments; S5, center axis shape data extraction: define the data structure of the tube shape, and convert the constructed center axis into the data structure representation, the parameters include length, arc, radius, and turning angle; S6, Graphics display: Display the original 3D workpiece drawing and the processed graphics containing only the pipe part on the user interface for the user to verify the analysis results; S7, user interaction: allows the user to adjust parameters through the graphical interface, including selecting the processing starting point of the closed figure; S8, data output: output the processed central axis shape data in a format suitable for subsequent processing, including generating a 2D DXF file or other required format.

7. The method for extracting the central axis and shape of a pipe according to claim 6, characterized in that: In step 2, the data analysis module also includes geometric error detection and repair functions to ensure the accuracy of the analysis results.

8. The method for extracting the central axis and shape of a pipe according to claim 6, characterized in that: In step 3, the extraction of the central axis segment of the pipe also includes automatic identification and elimination of non-pipe parts to simplify the processing process.

9. The method for extracting the central axis and shape of a pipe according to claim 6, characterized in that: In step 4, the central axis construction also includes checking and correcting the direction consistency of the central axis segments to ensure that all line segments have consistent directions.

10. The method for extracting the central axis and shape of a pipe according to claim 6, characterized in that: In step 6, the graphic display also includes a comparison view function, which simultaneously displays the original 3D model and the processed 2D graphics to facilitate intuitive comparison by the user.

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