A Digital Twin Ground Crack Virtual-Reality Domain Mapping Method

Abstract

The present invention discloses a method for mapping virtual and real domains of digital twin ground cracks, including: constructing a virtual scene ground model, triangulating it using the Delaunay triangulation algorithm to construct a set of ground crack cutting planes, using the set of cutting planes to cut the ground model by three-dimensional model space Boolean operations, constructing an offset bone array, performing skin binding between the bone array and the ground model based on skinning technology to generate the ground model information after virtual space cracks, recording the vertex information and spatial structure information of the ground model before and after cracks, exporting it as a GLTF format file, parsing the GLTF file, and constructing the mapping between the ground crack twin domain and the entity domain. This method provides a method for connecting the mapping interface between the entity domain ground and the twin domain ground, enabling the transmission and manifestation of sensor or geological analysis data in the real scene in the virtual space.

Description

Technical Field

[0001] The present invention relates to the technical field of digital twins, and more specifically, to a method for mapping the virtual and real domains of ground cracks in digital twins. Background Art

[0002] Digital twin is a simulation process that makes full use of physical models and sensor data, integrates multiple disciplines, multiple physical quantities, and multiple scales, and completes mapping in a virtual space, so as to reflect the entire life cycle process of the corresponding entity.

[0003] Taking geological disasters such as ground subsidence or ground deformation caused by geological changes as the main body, in the application fields of national land geological disasters, mine geological disasters, national energy (such as natural gas plants, gas gathering plants, water treatment plants), the losses caused by natural disasters caused by geological changes to human lives and national property are immeasurable. In recent years, with the rise of digital twin technology, whether it can play a role in bringing forth new ideas and taking a unique path in the prevention and protection work in the field of geological disasters has gradually attracted the attention of the country.

[0004] At present, the problems existing in the virtual-real domain mapping of ground cracks are as follows: First, the characteristic structure of real ground cracks cannot be fitted and simulated in the virtual space. Second, the vertex sets of the regions with the characteristic structure of real ground cracks in the virtual space are unevenly distributed, and the force points of the regions cannot be offset. Third, the data in the real scene where the cracks change cannot be transmitted and reflected in the virtual scene, and the parameter interface for simulating the state change of ground cracks in the virtual scene cannot be fitted. Summary of the Invention

[0005] The embodiments of the present invention provide a method for mapping the virtual and real domains of ground cracks in digital twins, including:

[0006] Constructing an initial ground model of the virtual scene based on the physical scene;

[0007] Triangulating the region to be cracked in the initial ground model using the Delaunay triangulation algorithm to construct a ground grid model with Delaunay triangular network characteristics;

[0008] Generating a set of cutting planes for the cracked region based on the fractal noise FractalNoises algorithm;

[0009] Using the set of cutting planes and the ground grid model with Delaunay triangular network characteristics to perform spatial Boolean operation cutting in sequence to generate a ground grid model with real crack cutting planes and Delaunay triangular network characteristics;

[0010] Construct an offset bone array for the ground mesh model with real crack sections and Delaunay triangulation characteristics, and bind the bone array to the ground model based on skinning technology to generate a virtual space cracked ground mesh model with skinning information;

[0011] Based on the 3D model Morph deformation algorithm, the vertex information and spatial structure information of the ground mesh model with real crack sections and Delaunay triangulation characteristics and the ground mesh model after the virtual space crack with skin information are recorded and exported into GLTF format files;

[0012] The GLTF file is parsed based on WebGL to construct the mapping between the ground crack twin domain and the entity domain.

[0013] Furthermore, the steps of constructing a ground mesh model with Delaunay triangulation characteristics include:

[0014] Get the initial vertex set P of the initial ground model init_Ground G ;

[0015] Construct a general Delaunay triangulation algorithm in the d-dimensional Euclidean space Ed - a point-by-point insertion algorithm to process the initial ground model, generating a ground mesh model end_Ground with Delaunay triangulation characteristics and its corresponding new vertex set Q G .

[0016] Furthermore, the step of generating a set of cross-section planes of the crack area based on the fractal noise algorithm includes:

[0017] Generate a uniformly subdivided plane mesh model init_CuttingPlane;

[0018] The vertex set P contained in the plane mesh model init_CuttingPlane C For each vertex coordinate x, y, and z, the FractalNoises algorithm is used to offset the three coordinate axes of x, y, and z in Euclidean space.

[0019] Generate the offset vertex set Q C Corresponding to the ground crack cutting plane end_CuttingPlane;

[0020] Construct a cutting plane set end_CuttingPlane_Group consisting of multiple cutting planes.

[0021] Furthermore, the steps of generating a ground mesh model having a true crack section and Delaunay triangulation characteristics include:

[0022] Use the mesh models in the end_CuttingPlane_Group of cutting planes to perform 3D model space Boolean operations on the ground mesh model end_Ground with Delaunay triangulation characteristics;

[0023] Generate a ground mesh model finalCracks_Ground with real crack cross-sections and Delaunay triangulation characteristics according to the results of the 3D model space Boolean operations.

[0024] Furthermore, the steps of generating the ground model after generating virtual space cracks include:

[0025] Construct an offset bone array Bone set within the area range of the ground mesh model finalCracks_Ground with real crack cross-sections and Delaunay triangulation characteristics;

[0026] Use the bone array Bone set for skinning and bone binding to generate a ground mesh model skinCracks_Ground with skin information.

[0027] Furthermore, the steps of recording the vertex information and spatial structure information of the ground mesh model with real crack cross-sections and Delaunay triangulation characteristics and the ground mesh model after virtual space cracks with skin information based on the 3D model Morph deformation algorithm include:

[0028] For the ground mesh model with real crack cross-sections and Delaunay triangulation characteristics, that is, the ground mesh model finalCracks_Ground before cracks, sort the vertex information and spatial structure information A - H starting with the prefix CracksStart_;

[0029] For the ground mesh model after virtual space cracks with skin information, that is, the ground mesh model Cracks01_Ground after cracks, sort the vertex information and spatial structure information A' - H' starting with the prefix CracksEnd_;

[0030] Based on the 3D model Morph deformation algorithm, record the vertex information and spatial structure information of the ground model before and after cracks.

[0031] Furthermore, the steps of constructing the mapping between the ground crack twin domain and the entity domain based on WebGL parsing of GLTF files include:

[0032] Parse the GLTF format file storing information in WebGL;

[0033] Index according to the name attribute;

[0034] Obtain the vertex information and spatial structure information CracksStart_A, CracksStart_B, …, CracksStart_H of the ground grid model with multiple main crack textures, and map them to 0 respectively;

[0035] Obtain the vertex information and spatial structure information CracksEnd_A’, CracksEnd_B’, …, CracksEnd_H’ of the ground grid model after cracking, and map them to 1 respectively;

[0036] The change from the interval of 0 to 1 is the process of the ground grid model changing from intact to cracked, that is, the mapping interface of the virtual and real domains of the ground crack;

[0037] Perform arbitrary assignments in the interval of 0 to 1 on the grid object that has completed the mapping interval of the virtual and real domains of the ground crack, or perform continuous assignments within the interval on the time axis, to obtain the state or process of the digital twin ground crack virtual and real domain mapping.

[0038] The embodiment of the present invention provides a method for mapping the virtual and real domains of a digital twin ground crack. Compared with the prior art, its beneficial effects are as follows:

[0039] 1. The ground crack characteristics fitted and simulated in the twin domain are more excellent.

[0040] 2. The ground grid model structure with crack characteristics in the twin domain is more stable.

[0041] 3. It provides a mapping interface for connecting the ground in the physical domain and the ground in the twin domain in the application fields related to geology and geological disasters in the digital twin field.

[0042] 4. It enables the transfer and manifestation of entities such as sensors or geological analysis data in the physical domain in the twin domain.

[0043] 5. It provides an efficient and feasible solution for the result diagnosis and prediction in the subsequent stages of the application fields related to geology and geological disasters in the digital twin field. Description of the Drawings

[0044] Figure 1 It is the implementation flowchart provided by the present invention;

[0045] Figure 2 It is the virtual scene ground model constructed based on the physical scene provided by the present invention. The area that needs to generate cracks is triangulated into uniform triangular faces using the Delaunay triangulation algorithm;

[0046] Figure 3The present invention provides a method for constructing the before and after results of a ground crack section based on the Fractal Noises algorithm.

[0047] FIG4 is a schematic diagram of using a cutting plane to cut through a ground model according to the present invention, wherein FIG4(a) is a schematic diagram of using a cutting plane to cut through an area of the ground model where a crack is to be generated using a Boolean operation in a three-dimensional model space, and FIG4(b) is a diagram of the ground crack generated by the Boolean operation in the three-dimensional model space and the result of an offset test in a virtual scene;

[0048] FIG5 is a schematic diagram of creating a skeleton array and identifying and naming the offset ground model provided by the present invention, wherein FIG5(a) shows the creation of an offset skeleton array for the cut-off ground model based on skinning technology after multiple spatial Boolean sectioning of the ground model, and FIG5(b) shows the offset ground model generated by offsetting the local bones of the offset skeleton array and identifying and naming it;

[0049] Figure 6 The present invention provides a 3D model based Morph deformation algorithm that records vertex information and spatial structure information before and after the ground model cracks;

[0050] Figure 7 The present invention provides a method for parsing GLTF files based on WebGL to obtain vertex information and spatial structure information of the stored ground mesh, and to construct a mapping between the ground crack twin domain and the entity domain. DETAILED DESCRIPTION

[0051] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0052] See also Figures 1 to 7 , an embodiment of the present invention provides a digital twin ground crack virtual-real domain mapping method, the method comprising:

[0053] Construct an initial ground model of the virtual scene based on the physical scene; triangulate the area to be cracked in the initial ground model using the Delaunay triangulation algorithm to construct a ground grid model with Delaunay triangular network characteristics; construct a ground crack cutting plane set based on the fractal noises algorithm; use the cutting plane set to perform a 3D grid model space Boolean operation cutting on the area to be cracked in the ground grid model with Delaunay triangular network characteristics to obtain a ground grid model with multiple main crack textures; construct an offset bone array based on the ground grid model with multiple main crack textures and perform skin binding between the bone array and the ground model based on the skinning technology to generate a ground model after virtual space cracks; based on the 3D model Morph deformation algorithm, record the vertex information and spatial structure information of the ground grid model with multiple main crack textures and the ground model after cracks, and export a GLTF format file; based on WebGL, parse the GLTF file, obtain the vertex information and spatial structure information storing the ground grid, and construct the mapping between the ground crack twin domain and the entity domain.

[0054] Example:

[0055] 1.1 For the virtual scene ground model constructed based on the physical scene, triangulate the area where cracks need to be generated into uniform triangular faces using the Delaunay triangulation algorithm.

[0056] For any digital ground model grid, it contains the vertex information that makes up the model, that is, the initial vertex set PG (or scatter point set) of the initial ground model init_Ground. Figure 2 In, for the digital ground model based on the scatter point set, by using the general algorithm for constructing Delaunay triangulation in the d-dimensional Euclidean space Ed - the point-by-point insertion algorithm, a ground grid model end_Ground with Delaunay triangular network characteristics can be generated while maintaining the original ground model structure, and its corresponding new vertex set QG.

[0057] That is, in the Delaunay triangular network formed by the vertex set QG contained in the ground model end_Ground after triangulation, there will be no other points within the circumcircle of any triangle (empty circle property); no matter where the construction starts from the area, the same result will be obtained eventually (uniqueness); when adding, deleting, or moving a vertex, only the adjacent triangles will be affected (local property).

[0058] These three properties provide the stability of the ground model spatial structure for the subsequent cutting calculation of ground cracks and sufficient vertex subdivision for vertex offset under the subsequent ground model structure.

[0059] 1.2 Constructing a Ground Crack Section Set Based on the Fractal Noises Algorithm

[0060] To construct the spatial morphology of cracks in the ground model, it is necessary to fit and simulate the cross-section of geological cracks in the real environment. Fractal Noises is a random algorithm commonly used in computer graphics to simulate self-similar processes in nature.

[0061] Figure 3 In the code, a uniformly subdivided cutting plane (init_CuttingPlane) is used to offset the coordinates (x, y, z) of each vertex in the vertex set PC contained in its model mesh along the x, y, and z axes in Euclidean space using the Fractal Noises algorithm. This generates the model mesh (end_CuttingPlane) corresponding to the offset vertex set QC, i.e., the ground crack cut surface. This cut surface mesh exhibits the self-similar morphological characteristics of real-world ground cracks. Real ground cracks often produce multiple main crack textures, and similarly, a cut surface set (end_CuttingPlane_Group) composed of multiple cut surfaces can be constructed.

[0062] 1.3 Use the cutting plane set to perform three-dimensional mesh model space Boolean operation cutting on the area where cracks need to be generated in the ground model

[0063] In the process of Boolean operations on 3D mesh models, the complex spatial structure of the multiple mesh models being operated on, or the spatial polygonal edges of the mesh models, are often the cause of errors in the results of spatial Boolean operations, especially for complex data. This can manifest as holes or missing vertex information in the mesh model after operation. However, for ground meshes with Delaunay triangulation characteristics, the structural stability of the meshes makes the results of spatial Boolean operations more accurate.

[0064] In 1.1 and 1.2, a ground mesh model end_Ground with Delaunay triangulation characteristics and a set of cutting planes end_CuttingPlane_Group with self-similar forms of ground cracks in the real scene were respectively constructed. In Figure 4(a), a spatial Boolean operation was performed on the ground mesh model using the cutting plane to obtain a ground mesh model cracks_Ground with real crack sections and Delaunay triangulation characteristics. In Figure 4(b), the test result diagrams before and after offsetting the cracked ground mesh model cracks_Ground obtained by the spatial Boolean operation are shown. The ground model end_Ground and the set of cutting planes end_CuttingPlane_Group were successively subjected to spatial Boolean operation cutting to obtain a ground mesh model finalCracks_Ground with multiple main crack textures.

[0065] 1.4 Construct an offset bone array for the ground model after cutting, and perform skinning binding between the bone array and the ground model based on skinning technology to generate the ground model information after generating virtual space cracks

[0066] In the real scene, when cracks or collapses occur in the ground geology, the structure of the physical entity's crack or collapse area undergoes extrusion or fracture. If the evolution of the change process of the physical entity's ground needs to be carried out in the virtual space, then the ground model in the virtual space needs to have approximate characteristics to the real ground in the physical entity when cracks occur, that is, the offset of the vertex structure in the crack area of the ground mesh in the virtual space.

[0067] In Figure 5(a), based on skinning technology, an offset bone array Bone set was constructed for the finalCracks_Ground ground mesh model after cutting and skinning binding was performed to obtain the skinned ground mesh model skinCracks_Ground.

[0068] In Figure 5(b), the local bones in the bone array Bone set are offset to obtain the ground mesh model Cracks01_Ground in the state after cracks, and then the corresponding ground mesh model will generate the form of cracks due to the offset of the bones. That is, the offset in the x and y axes in the Euclidean space corresponds to the cracks or extrusion of the real ground, and the offset in the z axis in the Euclidean space corresponds to the collapse or fracture of the real ground.

[0069] Specifically, in reality, in application scenarios such as geological monitoring, a sensor array (such as displacement sensors, etc.) will be deployed in the ground area to be monitored. Here, let the array set be S, and the offset values of the points where the sensors are located in the real space (x, y, z) due to geological changes will be returned. Then, the spatial positions of the offset bone arrays in the virtual space correspond to the spatial positions of the sensors in the real scenario; for two points that are far apart in the real sensor array, they will be segmented and subdivided in the virtual space.

[0070] Then, the set of offset bone arrays Bone in the virtual space is greater than or equal to S, and the spatial positions of the offset bones in the virtual space are the spatial positions of the sensors in the real scenario. When Bone is greater than S, the excess part is the equidistant segmentation points of two adjacent points in the S set array.

[0071] Specifically, the ground grid model skinCracks_Ground obtained in 1.4 can be stored and exported using the GLTF model format according to the requirements of the actual application scenario (such as performing virtual-real domain mapping of digital twin ground cracks based on the sensor points). In this step, the GLTF format file can also be directly parsed in WebGL in 1.6 to extract the information of the offset bone array. At this time, the virtual-real domain mapping relationship is the mapping between the spatial coordinates of the offset bone array and the position coordinates of the sensor array. This method also belongs to the scope protected by the present invention.

[0072] 1.5 Based on the 3D model Morph deformation algorithm, record the vertex information and spatial structure information of the ground model before and after the crack, and store and export the GLTF format file after naming and identification.

[0073] Figure 6 In this process, for the ground grid model finalCracks_Ground before the crack, start with the prefix CracksStart_ and sort from A to H. For the ground grid model after the crack, start with the prefix CracksEnd_ and sort from A' to H'. Based on the 3D model Morph deformation algorithm, record the vertex information and spatial structure information of the ground model before and after the crack, and store and export the information using the GLTF model format.

[0074] Specifically, the information stored in the GLTF file in 1.4 is the information of the offset bone array, the ground grid model, and its skin information. The information stored in the GLTF file in 1.5 is the vertex information and spatial structure information of the ground grid model in the states before and after the crack.

[0075] Specifically, the real-world instantiation listed in Patent 1.5 of this patent is the state before and after the crack of the single-stage ground model. In the actual application scenario, there will be a multi-stage evolution process of ground cracks. The multi-stage ground crack states can also be stored and recorded, and parsed and mapped to the virtual-real domain interval in 1.6. The virtual-real domain mapping of multi-stage ground cracks also belongs to the protection scope of the present invention.

[0076] 1.6 Parse the GLTF file based on WebGL to obtain the vertex information and spatial structure information of the stored ground grid, and construct the mapping between the ground crack twin domain and the entity domain

[0077] Parse the GLTF file storing information in WebGL to obtain the vertex information and spatial structure information of the ground grid. Index through the name attribute of the ground grid model (i.e., the naming identifier in 1.5) to obtain the vertex information and spatial structure information before the crack of the ground grid model {CracksStart_A, CracksStart_B, …, CracksStart_H}, which are respectively mapped to 0; obtain the vertex information and spatial structure information after the crack of the ground grid model {CracksEnd_A’, CracksEnd_B’, …, CracksEnd_H’}, which are respectively mapped to 1. Then the change from 0 to 1 in the interval [0,1] is the process of the ground grid model changing from intact to cracked, that is, the mapping interface of the ground crack virtual-real domain interval.

[0078] Figure 7 In, perform any assignment within the 0-1 interval on the grid object that has completed the ground crack virtual-real domain mapping interval, or perform continuous assignment within the interval on the time axis, and the state or process of the digital twin ground crack virtual-real domain mapping can be obtained.

[0079] The above discloses only several specific embodiments of the present invention. Those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the present invention. However, the embodiments of the present invention are not limited thereto, and any changes that can be thought of by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A digital twin ground crack virtual-real domain mapping method, characterized in that Including: Construct an initial ground model of the virtual scene based on the physical scene; Triangulate the area where cracks are to be generated in the initial ground model using the Delaunay triangulation algorithm to construct a ground grid model with Delaunay triangulation characteristics; Generate a uniformly subdivided plane grid model init_CuttingPlane; for each vertex coordinate x, y, z in the vertex set PC included in the plane grid model init_CuttingPlane, use the Fractal Noises algorithm to perform offsets in the x, y, and z coordinate axes in Euclidean space; generate the corresponding ground crack cutting plane end_CuttingPlane for the offset vertex set QC; construct a cutting plane set end_CuttingPlane_Group composed of multiple cutting planes; Use the cutting plane set to perform spatial Boolean operation cutting with the ground grid model with Delaunay triangulation characteristics in sequence to generate a ground grid model with real crack cut surfaces and Delaunay triangulation characteristics; Construct an offset bone array for the ground grid model with real crack cut surfaces and Delaunay triangulation characteristics, and perform skin binding between the bone array and the ground model based on skinning technology to generate a ground grid model with skin information after virtual space cracks; Based on the 3D model Morph deformation algorithm, record the vertex information and spatial structure information of the ground grid model with real crack cut surfaces and Delaunay triangulation characteristics and the ground grid model with skin information after virtual space cracks, and export GLTF format files; Based on WebGL, parse the GLTF file to construct the mapping between the ground crack twin domain and the entity domain.

2. The digital twin ground crack virtual-real domain mapping method according to claim 1, characterized in that, The steps of constructing the ground grid model with Delaunay triangulation characteristics include: Obtain the initial vertex set P of the initial ground model init_Ground G ; Construct a Delaunay triangulation in the d-dimensional Euclidean space Ed. The general point-by-point insertion algorithm processes the initial ground model to generate a ground grid model end_Ground with the characteristics of a Delaunay triangular mesh and its corresponding new vertex set Q G .

3. The digital twin ground crack virtual-real domain mapping method according to claim 2, characterized in that The steps of generating the ground grid model with real crack cut surfaces and Delaunay triangulation characteristics include: Use the grid models in the cutting plane set end_CuttingPlane_Group respectively to perform 3D model spatial Boolean operations on the ground grid model end_Ground with Delaunay triangulation characteristics; Generate a ground grid model finalCracks_Ground with real crack cut surfaces and Delaunay triangulation characteristics according to the results of the 3D model spatial Boolean operations.

4. The digital twin ground crack virtual-real domain mapping method according to claim 3, characterized in that The steps of generating the ground grid model with skin information after virtual space cracks include: Construct a set of offset bone arrays Bone in the area range of the ground grid model finalCracks_Ground with real crack cut surfaces and Delaunay triangulation characteristics; Use the set of bone arrays Bone to perform skin and bone binding to generate a ground grid model skinCracks_Ground with skin information.

5. A digital twin ground crack virtual-real domain mapping method according to claim 4, characterized in that, The steps of recording the vertex information and spatial structure information of the ground grid model with a real crack section and Delaunay triangulation characteristics and the ground grid model with skin information after virtual space cracks based on the 3D model Morph deformation algorithm include: For the ground grid model with a real crack section and Delaunay triangulation characteristics, that is, the ground grid model before cracks finalCracks_Ground, sort the vertex information and spatial structure information A-H starting with the prefix CracksStart_. For the ground grid model with skin information after virtual space cracks, that is, the ground grid model after cracks Cracks01_Ground, sort the vertex information and spatial structure information A'-H' starting with the prefix CracksEnd_. Based on the 3D model Morph deformation algorithm, record the vertex information and spatial structure information of the ground model before and after cracks.

6. The digital twin ground crack virtual-real domain mapping method according to claim 5, wherein, The steps of parsing the GLTF file based on WebGL to construct the mapping between the ground crack twin domain and the entity domain include: Parse the GLTF format file storing information in WebGL; Index according to the name attribute; Obtain the vertex information and spatial structure information CracksStart_A, CracksStart_B,..., CracksStart_H of the ground grid model with multiple main crack textures, and map them to 0 respectively; Obtain the vertex information and spatial structure information CracksEnd_A', CracksEnd_B',..., CracksEnd_H' of the ground grid model after cracks, and map them to 1 respectively; The change in the interval from 0 to 1 is the process of the ground grid model changing from intact to cracked, that is, the mapping interface of the ground crack virtual-real domain interval; Assign any value in the interval from 0 to 1 to the grid object that has completed the virtual-real domain mapping interval of the ground crack, or perform continuous assignment within the interval on the time axis to obtain the state or process of the digital twin ground crack virtual-real domain mapping.

Images