Flexible device deformation rapid modeling method and system based on FFD algorithm

Abstract

The invention provides a flexible device deformation rapid modeling method and system based on an FFD algorithm, and the method comprises the steps: model analysis: reading a model STL / NAS file, and analyzing the data in the file; control grid construction: generating a bounding box of the target model based on the vertex data, establishing a local coordinate system and obtaining control vertex coordinates; vertex mapping: normalizing model vertexes, and mapping the model vertexes to a local coordinate system; deformation control: displaying the control vertex by adopting a graphical interface, controlling deformation by modifying the absolute coordinate of the control vertex or adjusting the relative offset, recalculating the position of the model vertex in real time according to the new coordinate of the control vertex by adopting an FFD free deformation technology algorithm, and outputting a deformed STL or NAS file; and verifying and packaging. According to the method, on the basis of the FFD free deformation technology, smooth deformation of the complex three-dimensional model can be achieved through 27 control vertexes, and efficient and unified basic model support is provided for rapid electromagnetic calculation.

Description

Technical Field

[0001] This invention belongs to the field of computer technology and relates to the intersection of computational electromagnetics and computer-aided design technology, and in particular to a method and system for rapid modeling of deformation of flexible devices based on the FFD algorithm. Background Technology

[0002] Flexible devices, due to their lightweight, thinness, flexibility, and conformal characteristics, have broad application prospects in wearable systems, body area networks, and other fields. However, accurate modeling of the geometry of flexible devices during deformation is one of the key challenges in electromagnetic simulation. Traditional geometric modeling methods typically require rebuilding the model for each deformation state, which is inefficient and makes it difficult to guarantee the physical consistency of the deformation process. While existing commercial software (such as CST and HFSS) supports geometric modeling, they lack dedicated control modules for the deformation parameters of flexible devices, making it difficult to achieve parameterized driving and batch processing of the deformation process. Furthermore, the deformation of flexible devices involves complex three-dimensional structural changes, requiring the avoidance of mesh distortion, non-manifold structures, and other problems. Traditional methods have shortcomings in terms of deformation smoothness and computational stability.

[0003] Therefore, researching a rapid modeling scheme for the deformation of flexible devices is of urgent engineering significance and clear application value for shortening the R&D cycle of flexible devices, reducing testing costs, and improving design reliability. Summary of the Invention

[0004] To address the problems existing in current technologies, this invention provides a rapid deformation modeling method and system for flexible devices based on the FFD algorithm. It indirectly achieves parametric deformation control of the geometric model of the flexible device through changes in 27 control vertices in the Free Deformation (FFD) algorithm. This invention supports the parsing and processing of STL and NAS format files. Users can interactively adjust the coordinates of the control vertices through a graphical interface to quickly generate geometric models under bending, stretching, and other deformation states, and directly output them in a format compatible with electromagnetic simulation software. This invention encapsulates the deformation algorithm and interface operation into an independent executable program, eliminating the need for a professional modeling environment and significantly improving modeling efficiency and ease of use.

[0005] Compared to traditional manual modeling, which relies on engineer experience and is inefficient, lacks repeatability, and is difficult to tune parameters for complex surfaces described by multivariate functions, making it hard to support rapid iterative optimization, this application uses a three-level framework of "bounding box-parameter space-control points." First, the model vertices are mapped to local coordinates (s, t, u), and then 27 control points are used for... By dragging or numerical offsetting, the world coordinates are recalculated using the weights of the three-dimensional Bernstein basis functions, achieving smooth and continuous arbitrary distortion; the algorithm can maintain the mesh topology by only changing the control points, making it suitable for interactive and rapid shape adjustment.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for rapid deformation modeling of flexible devices based on the FFD algorithm includes the following steps:

[0008] Step 1, Model Analysis: Read the model STL / NAS file and analyze the vertex, triangle facet, and quadrilateral cell data in the file;

[0009] Step 2, Control Mesh Construction: Generate the bounding box of the target model based on vertex data, establish a local coordinate system and obtain the coordinates of the control vertices;

[0010] Step 3, Vertex Mapping: Normalize the model vertices and map them to the local coordinate system established in Step 2;

[0011] Step 4, Deformation Control: The control vertices are displayed using a graphical interface. Deformation is controlled by modifying the absolute coordinates of the control vertices or adjusting the relative offsets. The FFD free deformation technology algorithm is used to recalculate the position of the model vertices in real time based on the new coordinates of the control vertices, and outputs the deformed STL or NAS file.

[0012] Step 5, Verification and Packaging: Verify the accuracy of the STL or NAS file using CST / HFSS, and package the program into an EXE executable file based on QT.

[0013] Furthermore, step 1, before reading the model STL / NAS file, also includes: importing the model file through a graphical interface.

[0014] Furthermore, in step 1, a parameter with a value of 0 was added to the STL file during parsing.

[0015] Furthermore, step 2 specifically includes the following sub-steps:

[0016] Step 2.1: Find the minimum parallelepiped control mesh that encloses the target model by finding the extreme values ​​of the coordinates of each model vertex, and obtain the coordinates of 27 control vertices;

[0017] Step 2.2: Construct a local coordinate system based on the control grid.

[0018] Furthermore, the FFD free deformation technology algorithm is as follows:

[0019]

[0020] Where P(i,j,k) are the new coordinates of the frame control points, and l, m, and n are the number of grids divided on the S, T, and U coordinate axes, respectively.

[0021] This invention also provides a rapid deformation modeling system for flexible devices based on the FFD algorithm, used to implement a rapid deformation modeling method for flexible devices based on the FFD algorithm. The system includes: a file parser, a control mesh construction module, a vertex mapping module, a deformation control module, a verification and encapsulation module, and an interactive interface module. The file parser is used to parse STL / NAS files, store data, and output files. The control mesh construction module is used to generate bounding boxes and construct a local coordinate system based on the data parsed by the file parser. The vertex mapping module is used to obtain the normalized coordinates of the file vertices in the local coordinate system. The deformation control module is used to calculate the model vertex coordinates based on the new coordinates of the control vertices using the FFD algorithm, based on user operations, to achieve smooth deformation. The verification and encapsulation module is used to verify the accuracy of the deformed model file and encapsulate it into an EXE executable file. The interactive interface module is used to display the system's interactive interface, import files, collect user control actions, and display the deformation results.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] 1. This invention is based on FFD free deformation technology, which can achieve smooth deformation of complex 3D models through 27 control vertices. Compared with the traditional "destruction and reconstruction" modeling method, it greatly reduces the manual operation time and provides efficient and unified basic model support for rapid electromagnetic calculation.

[0024] 2. The present invention strictly maintains the topological integrity of the geometric model during deformation, avoids the generation of singularities and non-manifold structures, ensures that the deformed model can be directly used for electromagnetic simulation calculations, and guarantees the reliability of the calculation results.

[0025] 3. The parametric modeling method adopted in this invention lays the foundation for subsequent optimization design. It can drive complex geometric changes with a small number of parameters, realize simulation-driven design, and has important application value in filter optimization, antenna performance improvement and other aspects.

[0026] 4. This invention supports the parsing and processing of STL and NAS format files, and can be directly and seamlessly integrated with mainstream electromagnetic simulation software such as CST and HFSS, avoiding data loss problems caused by format conversion and ensuring efficient integration of geometric models and simulation environments.

[0027] 5. Users can drag and drop to import data through the graphical interface developed by QT and interactively adjust the control vertex coordinates for visual editing. The EXE executable file packaged by the present invention can run directly without QT, which greatly reduces the threshold for use and allows non-professional users to get started quickly.

[0028] 6. The present invention is particularly suitable for rapid geometric modeling of flexible microwave materials and devices under bending, stretching and other deformation states. It can meet the rapid modeling needs of various flexible microwave devices such as flexible antennas, wearable devices, and conformal antennas, and provides strong technical support for the research and development of emerging fields such as body area networks and smart clothing. Attached Figure Description

[0029] Figure 1 A schematic diagram of the process for rapid deformation modeling method of flexible devices based on FFD algorithm provided by the present invention;

[0030] Figure 2 A diagram illustrating the model parameter settings;

[0031] Figure 3 This is a schematic diagram of the import interface;

[0032] Figure 4 To modify the interface diagram;

[0033] Figure 5 This is a schematic diagram of the patch antenna before deformation.

[0034] Figure 6 This is a schematic diagram of the patch antenna after deformation. Detailed Implementation

[0035] The technical solutions provided by the present invention will be described in detail below with reference to specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0036] This invention provides a method for rapid deformation modeling of flexible devices based on the FFD algorithm, such as... Figure 1 As shown, it includes the following steps:

[0037] Step 1, Model Analysis: A graphical interface is developed using QT, supporting drag-and-drop file import, visual editing of vertices, and real-time preview of deformation results. Users import models by entering file paths in a graphical dialog box or by dragging and dropping. An STL / NAS file parser is developed based on C++ to read mesh vertex, facet, and element data, constructing the topology of the geometric model. STL files focus on parsing triangular facet information, while NAS files additionally handle node indices and quadrilateral elements, adapting to the multi-material partitioning requirements of electromagnetic simulation.

[0038] like Figure 2As shown, the model parsing module is implemented using Visual Studio and developed in C++ as an STL / NAS file parser. It extracts vertices and triangular faces by recognizing specific tags in the txt file. The file parser supports triangular face data from STL files and node (i.e., vertex) and element index structures from NAS files. Since the additional material properties of NAS files are difficult to unify with STL files, a parameter with a value of 0 was added to the class design to unify them, ensuring topological consistency of the model before and after deformation. The file parser completes the parsing of .stl and .nas mesh files, implementing file reading, data storage, and post-deformation output in C++.

[0039] Step 2: Control Mesh Construction: Based on the vertex-related data extracted in Step 1 using C++ encapsulated functions, a parallelepiped control mesh enclosing the target model is automatically generated, and the normalized coordinates of the model vertices in the local parametric coordinate system are calculated. This includes the following steps:

[0040] Step 2.1: Find the minimum parallelepiped control mesh that encloses the target model by finding the extreme values ​​of the (x,y,z) coordinates of each vertex, and obtain the coordinates of 27 control vertices.

[0041] Step 2.2: Construct a local coordinate system using this bounding box.

[0042] Step 3, Vertex Mapping: Normalize the extracted file vertices to obtain the normalized coordinates (s, t, u) of the model vertices in the local parametric coordinate system.

[0043] Step 4, Deformation Control: After system parsing, 27 control vertices are displayed in the graphical interface for user interaction. Users can click to modify absolute coordinates or double-click to adjust relative coordinates (offsets). The system calculates vertex weights using the Bernstein basis function through the FFD algorithm. Based on the new coordinates of the control vertices and the local coordinates (s,t,u) of the geometric model vertices, the world coordinates of the model vertices are recalculated in real time, mapping the vertices after position changes, thereby achieving smooth deformation and outputting a deformed STL or NAS file. Specifically, this includes the following steps:

[0044] Step 4.1: Move the control points of the deformable frame. The FFD algorithm uses the local coordinates (s, t, u) of the vertices of the geometric model, the world coordinates of the control points, and Bernstein polynomials to calculate the world coordinates of each vertex of the geometric model. The calculation formula is as follows:

[0045]

[0046] Where P(i,j,k) are the new coordinates of the frame control points, and l, m, and n are the number of grids divided on the S, T, and U coordinate axes, respectively.

[0047] The form of the nth-order Bernstein fundamental polynomial is:

[0048]

[0049] Where x represents the normalized parameter value, and v represents the integer index, satisfying 0≤v≤n, indicating which term in the polynomial it is.

[0050] Step 4.2: Call the save function to save the changed vertex information separately, saving them as STL files and NAS files respectively, in the same format as the original parsed file.

[0051] Step 5, Verification and Packaging: The deformed model can be saved in STL or NAS format, and its accuracy can be verified using CST / HFSS. Finally, the program is packaged into an EXE executable file based on QT, allowing it to run independently of the QT environment. Users can directly run the program to perform flexible device deformation operations without installing the QT environment.

[0052] The undeformed model of the flexible patch antenna after modeling using the method of this invention is shown in the figure below. Figure 5 As shown in the diagram, the deformed shape is as follows: Figure 6 As shown.

[0053] This invention also provides a rapid deformation modeling system for flexible devices based on the FFD algorithm, comprising: a file parser, a control mesh construction module, a vertex mapping module, a deformation control module, a verification and encapsulation module, and an interactive interface module. The file parser parses STL / NAS files, stores data, and outputs the file, specifically implementing step 1 of the rapid deformation modeling method for flexible devices based on the FFD algorithm. The control mesh construction module generates bounding boxes and constructs a local coordinate system based on the data parsed by the file parser, specifically implementing step 2. The vertex mapping module obtains the normalized coordinates of the file vertices in the local coordinate system, specifically implementing step 3. The deformation control module calculates the model vertex coordinates based on the new coordinates of the control vertices using the FFD algorithm according to user operations, achieving smooth deformation, specifically implementing step 4. The verification and encapsulation module verifies the accuracy of the deformed model file and encapsulates it into an EXE executable file, specifically implementing step 5.

[0054] The interactive interface module is used to display the system's interactive interface, import files, collect user control actions, and display the transformation results. Specifically, it uses QT's built-in interface file design dialog box, input boxes, buttons, labels, primary interfaces, secondary interfaces, etc., such as... Figure 3 , Figure 4 As shown, the program written in C++ has been ported, and functions such as confirm, cancel, save, and input have been linked through linker functions. The ability to drag and drop files directly into the dialog box has also been added, and new files can be added at any time without closing and restarting the program, making it convenient and fast.

[0055] It should be noted that the above content merely illustrates the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, various improvements and modifications can be made without departing from the principle of the present invention, and all such improvements and modifications fall within the scope of protection of the claims of the present invention.

Claims

1. A method for rapid deformation modeling of flexible devices based on the FFD algorithm, characterized in that, Includes the following steps: Step 1, Model Analysis: Read the model STL / NAS file and analyze the vertex, triangle facet, and quadrilateral cell data in the file; Step 2, Control Mesh Construction: Generate the bounding box of the target model based on vertex data, establish a local coordinate system and obtain the coordinates of the control vertices; Step 3, Vertex Mapping: Normalize the model vertices and map them to the local coordinate system established in Step 2; Step 4, Deformation Control: The control vertices are displayed using a graphical interface. Deformation is controlled by modifying the absolute coordinates of the control vertices or adjusting the relative offsets. The FFD free deformation technology algorithm is used to recalculate the position of the model vertices in real time based on the new coordinates of the control vertices, and outputs the deformed STL or NAS file. Step 5, Verification and Packaging: Verify the accuracy of the STL or NAS file using CST / HFSS, and package the program into an EXE executable file based on QT.

2. The method for rapid deformation modeling of flexible devices based on FFD algorithm according to claim 1, characterized in that, Step 1, before reading the model STL / NAS file, also includes: importing the model file through a graphical interface.

3. The method for rapid deformation modeling of flexible devices based on FFD algorithm according to claim 1, characterized in that, In step 1, a parameter with a value of 0 was added to the STL file during parsing.

4. The method for rapid deformation modeling of flexible devices based on FFD algorithm according to claim 1, characterized in that, Step 2 specifically includes the following sub-steps: Step 2.1: Find the minimum parallelepiped control mesh that encloses the target model by finding the extreme values ​​of the coordinates of each model vertex, and obtain the coordinates of 27 control vertices; Step 2.2: Construct a local coordinate system based on the control grid.

5. The method for rapid deformation modeling of flexible devices based on FFD algorithm according to claim 1, characterized in that, The FFD free deformation technology algorithm is as follows: ， Where P(i,j,k) are the new coordinates of the frame control points, and l, m, and n are the number of grids divided on the S, T, and U coordinate axes, respectively.

6. A rapid deformation modeling system for flexible devices based on the FFD algorithm, characterized in that, The method for rapid deformation modeling of flexible devices based on the FFD algorithm as described in any one of claims 1-5 includes: a file parser, a control mesh construction module, a vertex mapping module, a deformation control module, a verification and encapsulation module, and an interactive interface module. The file parser is used to parse STL / NAS files, store data, and output files. The control mesh construction module is used to generate bounding boxes and construct a local coordinate system based on the data parsed by the file parser. The vertex mapping module is used to obtain the normalized coordinates of the file vertices in the local coordinate system. The deformation control module is used to calculate the model vertex coordinates based on the new coordinates of the control vertices using the FFD algorithm, based on user operations, to achieve smooth deformation. The verification and encapsulation module is used to verify the accuracy of the deformed model file and encapsulate it into an EXE executable file. The interactive interface module is used to display the system's interactive interface, import files, collect user control actions, and display the deformation results.

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