A method and system for constructing a lightweight three-dimensional digital display model

Abstract

This application belongs to the technical field of lightweight structural 3D digital display model construction, specifically involving a method and system for constructing a lightweight structural 3D digital display model. The method includes: a point cloud model establishment step: discretizing the structural model to establish a point cloud model; a point cloud extraction step: traversing the cross-sections of the point cloud model to extract the outer contour point cloud; a point cloud lightweighting processing step: performing lightweighting processing on the outer contour point cloud to reduce its quantity; a display model reconstruction step: reconstructing a smooth model based on the outer contour point cloud to obtain a 3D digital display model; and a display model inspection step: performing a quality inspection on the 3D digital display model.

Description

Technical Field

[0001] The present application belongs to the technical field of constructing a lightweight three-dimensional digital display model, and specifically relates to a method and a system for constructing a lightweight three-dimensional digital display model. Background Art

[0002] The static strength ground test of aircraft structure is a necessary way to verify the strength of aircraft. During the static strength ground test, strain gauges are pasted on the key parts of the structure to monitor the structural strain response. In order to better obtain the strain results, the collected strain data is usually displayed in the form of cloud maps. For this purpose, it is necessary to establish a three-dimensional digital display model in advance. The three-dimensional digital display model has the typical shape of the test structure, and a cloud map is attached to it to display the strain data. In order to meet the real-time display, the scale of the three-dimensional digital display model cannot be too large, and the complete test structure model needs to be lightweight. For this, most of the lightweight three-dimensional digital display models are manually established, which is cumbersome, time-consuming and laborious.

[0003] This application is proposed in view of the above-mentioned technical defects. Summary of the invention

[0004] The purpose of the present application is to provide a method and system for constructing a lightweight three-dimensional digital display model, so as to overcome or alleviate at least one of the known technical defects.

[0005] The technical solution of this application is:

[0006] On the one hand, a method for constructing a lightweight three-dimensional digital display model is provided, comprising:

[0007] Steps for establishing a point cloud model: discretize the structural model and establish a point cloud model;

[0008] Point cloud extraction steps: traverse the point cloud model section and extract the outer contour point cloud;

[0009] Point cloud lightweight processing steps: lightweight processing of the outer contour point cloud to reduce the number of outer contour point clouds;

[0010] Display model reconstruction step: reconstructing a smooth model based on the outer contour point cloud to obtain a three-dimensional digital display model;

[0011] Display model inspection steps: perform a quality inspection on the three-dimensional digital display model. If the three-dimensional digital display model cannot meet the display requirements, re-extract the outer contour point cloud, perform lightweight processing on the outer contour point cloud, and reconstruct the smooth model to obtain the three-dimensional digital display model for quality inspection; if the three-dimensional digital display model can meet the display requirements, save the three-dimensional digital display model in the required format.

[0012] Optionally, in the above-mentioned method for constructing a lightweight three-dimensional digital display model of a structure, in the step of establishing a point cloud model, if the structural model is a CATIA model, the .stp format file is converted into a point cloud file using CloudCompare software and saved in .txt format;

[0013] If the structural model is a Nastran model, extract the node coordinate information from the .bdf format file and save it in .txt format.

[0014] Optionally, in the above-mentioned method for constructing a lightweight three-dimensional digital display model, in the point cloud extraction step, the cross-section of the point cloud model is traversed by cross-section sampling and slicing, the entire point cloud model is scanned, the outer contour points are found, and the outer contour point cloud is extracted;

[0015] The width of the cross-sectional sampling slice is 1 mm. The angle criterion method is used for the points within the cross-sectional sampling slice to extract the outer contour point cloud and filter out the point cloud inside the structure. Specifically:

[0016] Project the points in the cross-sectional sampling slice to the middle surface of the cross-sectional sampling slice, determine whether each point is an outer contour point one by one, and extract it. For any point p, connect the adjacent points of point p with point p in a counterclockwise direction to form a series of angles , if the largest angle If it is greater than the set threshold of 90°, point p is judged to be an outer contour point.

[0017] Optionally, in the above-mentioned method for constructing a lightweight three-dimensional digital display model of a structure, in the step of lightweight processing of the point cloud, the outer contour point cloud is lightweight processed by a sampling method or a compression algorithm of a geometric structure;

[0018] Sampling methods include random sampling, grid sampling, and geometric sampling.

[0019] Optionally, in the above-mentioned method for constructing a lightweight three-dimensional digital display model, in the display model reconstruction step, CloudCompare software is used to import the outer contour point cloud, reconstruct the smooth model, and obtain the three-dimensional digital display model;

[0020] In the display model checking step, when the three-dimensional digital display model can meet the display requirements, the three-dimensional digital display model is saved in a .bdf format.

[0021] On the other hand, a lightweight three-dimensional digital display model construction system is provided to implement the lightweight three-dimensional digital display model construction method, comprising:

[0022] Point cloud model building module, used to discretize the structural model and build a point cloud model;

[0023] Point cloud extraction module, used to traverse the cross section of the point cloud model and extract the outer contour point cloud;

[0024] Point cloud lightweight processing module, used to perform lightweight processing on the outer contour point cloud to reduce the number of outer contour point clouds;

[0025] A display model reconstruction module is used to reconstruct a smooth model based on the outer contour point cloud to obtain a three-dimensional digital display model;

[0026] The display model inspection module is used to perform quality inspection on the three-dimensional digital display model. If the three-dimensional digital display model cannot meet the display requirements, the outer contour point cloud is re-extracted, the outer contour point cloud is lightweight processed, and the smoothing model is reconstructed to obtain the three-dimensional digital display model for quality inspection; if the three-dimensional digital display model can meet the display requirements, the three-dimensional digital display model is saved in the required format.

[0027] Optionally, in the above-mentioned structural lightweight three-dimensional digital display model building system, in the point cloud model building module, if the structural model is a CATIA model, the .stp format file is converted into a point cloud file using CloudCompare software and saved in .txt format;

[0028] If the structural model is a Nastran model, extract the node coordinate information from the .bdf format file and save it in .txt format.

[0029] Optionally, in the above-mentioned structural lightweight three-dimensional digital display model construction system, in the point cloud extraction module, the cross-section of the point cloud model is traversed by cross-section sampling slices, the entire point cloud model is scanned, the outer contour points are found, and the outer contour point cloud is extracted;

[0030] The width of the cross-sectional sampling slice is 1 mm. The angle criterion method is used for the points within the cross-sectional sampling slice to extract the outer contour point cloud and filter out the point cloud inside the structure. Specifically:

[0031] Project the points in the cross-sectional sampling slice to the middle surface of the cross-sectional sampling slice, determine whether each point is an outer contour point one by one, and extract it. For any point p, connect the adjacent points of point p with point p in a counterclockwise direction to form a series of angles , if the largest angle If it is greater than the set threshold of 90°, point p is judged to be an outer contour point.

[0032] Optionally, in the above-mentioned structural lightweight three-dimensional digital display model construction system, in the point cloud lightweight processing module, the outer contour point cloud is lightweight processed by a sampling method or a geometric structure compression algorithm;

[0033] Sampling methods include random sampling, grid sampling, and geometric sampling.

[0034] Optionally, in the above-mentioned structural lightweight three-dimensional digital display model construction system, in the display model reconstruction module, CloudCompare software is used to import the outer contour point cloud, reconstruct the smooth model, and obtain the three-dimensional digital display model;

[0035] In the display model checking module, when the three-dimensional digital display model can meet the display requirements, the three-dimensional digital display model is saved in .bdf format.

[0036] This application has at least the following beneficial technical effects:

[0037] A method and system for constructing a lightweight three-dimensional digital display model of a structure are provided. By discretizing the structural model, a point cloud model is established, and then the outer contour point cloud is extracted, lightweight processing is performed, and a smooth model is reconstructed. The three-dimensional digital display model can be constructed conveniently and quickly with high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of a method for constructing a structurally lightweight three-dimensional digital display model provided in an embodiment of the present application;

[0039] Figure 2 is a schematic diagram of a point cloud model provided in an embodiment of the present application;

[0040] Figure 3 is a schematic diagram of an outer contour point cloud provided in an embodiment of the present application;

[0041] Figure 4 It is a schematic diagram of a structurally lightweight three-dimensional digital display model building system provided in an embodiment of the present application.

[0042] In order to better illustrate the present embodiment, some contents of the drawings may be omitted, enlarged or reduced, which is only used for illustrative purposes and should not be construed as limiting the present application. DETAILED DESCRIPTION

[0043] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0044] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application should be the common meanings understood by those skilled in the art in the field to which this application belongs. The term "include" used in the description of this application means that the concepts appearing before the term include the concepts listed after the term and their equivalents, without excluding other related concepts.

[0045] A method for constructing a lightweight three-dimensional digital display model, such as Figure 1 shown.

[0046] Steps to establish the point cloud model: discretize the structural model and establish the point cloud model, such as Figure 2 shown.

[0047] If the structural model is a CATIA model, use CloudCompare software to convert the .stp format file into a point cloud file and save it in .txt format.

[0048] If the structural model is a Nastran model, the coordinate information of the nodes in the .bdf format file is extracted and saved in a .txt format. The coordinate information of the nodes in the .bdf format file can be extracted by programming.

[0049] Point cloud extraction steps: traverse the point cloud model section and extract the outer contour point cloud, such as Figure 3 shown.

[0050] Use cross-section sampling and slicing to traverse the cross-section of the point cloud model, scan the entire point cloud model, find the outer contour points, and extract the outer contour point cloud.

[0051] The width of the cross-sectional sampling slice is usually 1 mm. The angle criterion method is used for the points in the cross-sectional sampling slice to extract the outer contour point cloud and filter out the point cloud inside the structure. The specific reference is as follows:

[0052] Project the points in the cross-sectional sampling slice to the middle surface of the cross-sectional sampling slice, determine whether each point is an outer contour point one by one, and extract it. For any point p, connect the adjacent points of point p with point p in a counterclockwise direction to form a series of angles. , if the largest angle If the angle is greater than the set threshold, the point p is judged to be an outer contour point, otherwise the point p is judged to be a point inside the structure. The set threshold can usually be 90°.

[0053] Point cloud lightweight processing steps: lightweight processing of the outer contour point cloud to reduce the number of outer contour point clouds.

[0054] The outer contour point cloud is lightweighted through sampling method or geometric structure compression algorithm.

[0055] Sampling methods include random sampling, grid sampling, and geometric sampling. The geometric sampling method determines the sampling density through geometric information such as slope, which can better retain local features. The grid sampling method divides the three-dimensional space into three-dimensional grids, and each grid retains a point replacement. Its sampling efficiency is high and the distribution is uniform.

[0056] Display model reconstruction step: Based on the outer contour point cloud, reconstruct the smooth model to obtain a three-dimensional digital display model.

[0057] Use CloudCompare software to import the outer contour point cloud, reconstruct the smooth model, and obtain the three-dimensional digital display model.

[0058] Display model inspection steps: perform a quality inspection on the three-dimensional digital display model. If the three-dimensional digital display model cannot meet the display requirements, adjust the relevant parameters, re-extract the outer contour point cloud, perform lightweight processing on the outer contour point cloud, and reconstruct the smoothing model to obtain the three-dimensional digital display model for quality inspection; if the three-dimensional digital display model can meet the display requirements, save the three-dimensional digital display model in the required format for output and application.

[0059] The 3D digital display model can usually be saved in .bdf format.

[0060] A lightweight three-dimensional digital display model construction system is used to implement the lightweight three-dimensional digital display model construction method, such as Figure 4 shown.

[0061] The point cloud model building module is used to discretize the structural model and build a point cloud model.

[0062] If the structural model is a CATIA model, use CloudCompare software to convert the .stp format file into a point cloud file and save it in .txt format.

[0063] If the structural model is a Nastran model, extract the node coordinate information from the .bdf format file and save it in .txt format.

[0064] The point cloud extraction module is used to traverse the cross section of the point cloud model and extract the outer contour point cloud.

[0065] Use cross-section sampling and slicing to traverse the cross-section of the point cloud model, scan the entire point cloud model, find the outer contour points, and extract the outer contour point cloud.

[0066] The width of the cross-sectional sampling slice is usually 1 mm. The angle criterion method is used for the points in the cross-sectional sampling slice to extract the outer contour point cloud and filter out the point cloud inside the structure. The specific reference is as follows:

[0067] Project the points in the cross-sectional sampling slice to the middle surface of the cross-sectional sampling slice, determine whether each point is an outer contour point one by one, and extract it. For any point p, connect the adjacent points of point p with point p in a counterclockwise direction to form a series of angles. , if the largest angle If the angle is greater than the set threshold, the point p is judged to be an outer contour point, otherwise the point p is judged to be a point inside the structure. The set threshold can usually be 90°.

[0068] The point cloud lightweight processing module is used to perform lightweight processing on the outer contour point cloud to reduce the number of outer contour point clouds.

[0069] The outer contour point cloud is lightweighted through sampling method or geometric structure compression algorithm.

[0070] Sampling methods include random sampling, grid sampling, and geometric sampling. The geometric sampling method determines the sampling density through geometric information such as slope, which can better retain local features. The grid sampling method divides the three-dimensional space into three-dimensional grids, and each grid retains a point replacement. Its sampling efficiency is high and the distribution is uniform.

[0071] The display model reconstruction module reconstructs the smooth model based on the outer contour point cloud to obtain a three-dimensional digital display model.

[0072] Use CloudCompare software to import the outer contour point cloud, reconstruct the smooth model, and obtain the three-dimensional digital display model.

[0073] The display model inspection module is used to perform quality inspection on the three-dimensional digital display model. If the three-dimensional digital display model cannot meet the display requirements, the relevant parameters are adjusted, the outer contour point cloud is re-extracted, the outer contour point cloud is lightweight processed, and the smoothing model is reconstructed to obtain the three-dimensional digital display model for quality inspection; if the three-dimensional digital display model can meet the display requirements, the three-dimensional digital display model is saved in the required format for output and application.

[0074] The 3D digital display model can usually be saved in .bdf format.

[0075] The method and system for constructing a lightweight three-dimensional digital display model of a structure disclosed in the above-mentioned embodiment discretizes the structural model, establishes a point cloud model, and then extracts the outer contour point cloud, performs lightweight processing, and reconstructs a smooth model. It can easily and quickly construct a three-dimensional digital display model and support the display of strain data of static strength ground tests of aircraft structures.

[0076] In addition, technicians in the field should also be able to realize that the various modules and units of the lightweight three-dimensional digital display model construction system disclosed in the embodiments of the present application can be implemented by electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, this application generally describes them according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Technicians in the field can choose to adopt different methods to implement the described functions for each specific application and its actual constraints, but such implementation should not be considered to be beyond the scope of this application.

[0077] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A method for constructing a lightweight three-dimensional digital display model, characterized in that: include: Steps for establishing a point cloud model: discretize the structural model and establish a point cloud model; Point cloud extraction steps: traverse the point cloud model section and extract the outer contour point cloud; Point cloud lightweight processing steps: lightweight processing of the outer contour point cloud to reduce the number of outer contour point clouds; Display model reconstruction step: reconstructing a smooth model based on the outer contour point cloud to obtain a three-dimensional digital display model; Display model inspection step: perform a quality inspection on the three-dimensional digital display model. If the three-dimensional digital display model cannot meet the display requirements, re-extract the outer contour point cloud, perform lightweight processing on the outer contour point cloud, and reconstruct the smoothing model to obtain the three-dimensional digital display model for quality inspection; if the three-dimensional digital display model can meet the display requirements, save the three-dimensional digital display model in a required format; In the step of establishing the point cloud model, if the structural model is a CATIA model, use CloudCompare software to convert the .stp format file into a point cloud file and save it in .txt format; If the structural model is a Nastran model, extract the node coordinate information in the .bdf format file and save it in .txt format; In the point cloud extraction step, the cross-section of the point cloud model is traversed by cross-section sampling and slicing, the entire point cloud model is scanned, the outer contour points are found, and the outer contour point cloud is extracted; The width of the cross-sectional sampling slice is 1 mm. The angle criterion method is used for the points within the cross-sectional sampling slice to extract the outer contour point cloud and filter out the point cloud inside the structure. Specifically: Project the points in the cross-sectional sampling slice to the middle surface of the cross-sectional sampling slice, determine whether each point is an outer contour point one by one, and extract it. For any point p, connect the adjacent points of point p with point p in a counterclockwise direction to form a series of angles θ1, θ2, ..., θ n , if the largest angle θ max If it is greater than the set threshold of 90°, point p is judged to be an outer contour point.

2. The method for constructing a lightweight three-dimensional digital display model according to claim 1, characterized in that: In the point cloud lightweight processing step, the outer contour point cloud is lightweighted by using a sampling method or a geometric structure compression algorithm; Sampling methods include random sampling, grid sampling, and geometric sampling.

3. The method for constructing a lightweight three-dimensional digital display model according to claim 2, characterized in that: In the display model reconstruction step, CloudCompare software is used to import the outer contour point cloud, reconstruct the smooth model, and obtain the three-dimensional digital display model; In the display model checking step, when the three-dimensional digital display model can meet the display requirements, the three-dimensional digital display model is saved in a .bdf format.

4. A lightweight three-dimensional digital display model construction system, used to implement the lightweight three-dimensional digital display model construction method of claim 1, characterized in that: include: Point cloud model building module, used to discretize the structural model and build a point cloud model; Point cloud extraction module, used to traverse the cross section of the point cloud model and extract the outer contour point cloud; Point cloud lightweight processing module, used to perform lightweight processing on the outer contour point cloud to reduce the number of outer contour point clouds; A display model reconstruction module is used to reconstruct a smooth model based on the outer contour point cloud to obtain a three-dimensional digital display model; The display model inspection module is used to perform a quality inspection on the three-dimensional digital display model. If the three-dimensional digital display model cannot meet the display requirements, the outer contour point cloud is re-extracted, the outer contour point cloud is lightweight processed, and a smoothing model is reconstructed to obtain the three-dimensional digital display model for quality inspection; if the three-dimensional digital display model can meet the display requirements, the three-dimensional digital display model is saved in a required format; In the point cloud model building module, if the structural model is a CATIA model, use CloudCompare software to convert the .stp format file into a point cloud file and save it in .txt format; If the structural model is a Nastran model, extract the node coordinate information in the .bdf format file and save it in .txt format; In the point cloud extraction module, the cross-section sampling slices are used to traverse the cross-section of the point cloud model, scan the entire point cloud model, find the outer contour points, and extract the outer contour point cloud; The width of the cross-sectional sampling slice is 1 mm. The angle criterion method is used for the points within the cross-sectional sampling slice to extract the outer contour point cloud and filter out the point cloud inside the structure. Specifically: Project the points in the cross-sectional sampling slice to the middle surface of the cross-sectional sampling slice, determine whether each point is an outer contour point one by one, and extract it. For any point p, connect the adjacent points of point p with point p in a counterclockwise direction to form a series of angles θ1, θ2, ..., θ n , if the largest angle θ max If it is greater than the set threshold of 90°, point p is judged to be an outer contour point.

5. The lightweight three-dimensional digital display model building system according to claim 4 is characterized in that: In the point cloud lightweight processing module, the outer contour point cloud is lightweighted by using sampling method or geometric structure compression algorithm; Sampling methods include random sampling, grid sampling, and geometric sampling.

6. The lightweight three-dimensional digital display model building system according to claim 5, characterized in that: In the display model reconstruction module, CloudCompare software is used to import the outer contour point cloud, reconstruct the smooth model, and obtain the three-dimensional digital display model; In the display model checking module, when the three-dimensional digital display model can meet the display requirements, the three-dimensional digital display model is saved in .bdf format.

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