Method for generating karst cave 3D printing digital model, storage medium and equipment

Abstract

The invention relates to a method for generating a karst cave 3D printing digital model, a storage medium and equipment, and the generation method comprises the following steps: analyzing a seismic data file in an SEGY format; arranging and storing X and Y coordinates, trace gathers (CDP) and seismic attribute data of a specified main measuring line seismic interpretation profile (Inline) and a tie line seismic interpretation profile (Xline) corresponding to each seismic data point in an index mode; generating a corresponding orthogonal grid model on the basis of the seismic data points; searching and extracting a karst cave in the orthogonal grid model according to the seismic data information of the orthogonal grid model and each grid unit, then identifying all boundary surfaces participating in forming a karst cave boundary, and processing the boundary surfaces to obtain a karst cave contour represented by a triangular grid; and outputting and storing the three-dimensional contour of the karst cave oil reservoir model obtained in the step 3.4 according to an STL file format. The STL model is constructed by identifying and analyzing the seismic data in the SEGY format, and a new tool is provided for smooth development of a 3D printing physical model.

Description

Technical Field

[0001] The present invention relates to the field of karst cave model generation, and particularly to a method, a storage medium and a device for generating a 3D printing digital model of a karst cave. Background Art

[0002] Some fracture-cavity type reservoirs are composed of fracture-cavity bodies with different sizes and shapes. There is complex multi-fluid-state coupled flow in the reservoir, and it is necessary to study the multi-phase flow laws of oil, gas and water in the reservoir by means of physical experiment methods. Due to the particularity of the reservoir space, conventional sand filling methods and cementing methods cannot be used to make physical models of fracture-cavity type reservoirs, and the organic glass etching method (chemical etching and laser engraving method) also has many disadvantages, which limits the development of physical experiment simulation.

[0003] In recent years, 3D printing technology has developed rapidly, and applying 3D printing technology to physical model experiments of fracture-cavity reservoirs has obvious advantages. Compared with traditional physical model preparation methods such as organic glass, 3D printed physical models can print transparent models similar to the spatial morphology of real reservoirs according to the size ratio and shape characteristics of real fracture-cavities through computer control.

[0004] The STL file format is the standard file format for 3D printing digital models. Almost all rapid prototyping machines can receive the STL file format for printing. However, at present, there is a lack of a reliable digital model parameter source for the preparation of 3D printed physical models.

[0005] Three-dimensional seismic is an important link in the process of geophysical exploration. By arranging grid-shaped or circular data acquisition points on the ground, seismic wave information reflected by underground strata is collected, and after various processes, a three-dimensional data volume file is formed. The standard data format of seismic data is the SEGY format. SEGY format seismic data is generally organized in units of seismic traces, and it is one of the standard tape data formats proposed by SE6 (Society of Exploration Geophysicists). It is one of the most common formats for seismic data in the petroleum exploration industry.

[0006] The karst cave bodies in fracture-cavity reservoirs are generally identified and characterized through seismic data interpretation, and a three-dimensional geological model is constructed in geological modeling software represented by Petrel. This process involves the cooperation of multiple professional software, has a high use threshold and inconvenient operation, and the operation method to obtain accurate modeling results is complex and costly, which brings great inconvenience to the development of 3D printed physical model experiments. Summary of the Invention

[0007] The present invention solves the problem that there is currently no suitable method to convert seismic data in SEGY format into a digital model for 3D printing of a karst cave model, which is not convenient for conducting 3D printing physical model experiments based on SEGY format seismic data. The present invention provides a method, a storage medium and a device for generating a digital model for 3D printing of a karst cave to solve this technical problem. By directly constructing an STL model by identifying and analyzing SEGY format seismic data, the steps of generating a digital model for 3D printing of a karst cave are simplified, providing a new tool for the smooth development of 3D printing physical models, with simple operation and low cost.

[0008] To solve the above technical problems, the technical solution of the present invention is as follows:

[0009] A method for generating a digital model for 3D printing of a karst cave, comprising the following steps:

[0010] S1. Analyze the SEGY format seismic data file, read the seismic data information including the X and Y coordinates, the common depth point (CDP) and the seismic attribute data of the specified main survey line seismic interpretation profile (Inline) and the connecting line seismic interpretation profile (Xline), determine each seismic data point with (Inline, Xline) as the index, and store the seismic data information corresponding to each seismic data point separately;

[0011] S2. Generate a grid based on the X and Y coordinates of each seismic data point to obtain an orthogonal grid model, and respectively associate the seismic data information of each seismic data point with the corresponding grid;

[0012] S3. Find the same type of connected regions according to the orthogonal grid model and the seismic data information of each grid unit to extract the karst caves in the orthogonal grid model, then identify all the boundary surfaces of each grid participating in forming the karst cave boundary, and perform triangulation on the boundary surfaces to obtain a karst cave contour represented by triangular meshes;

[0013] S4. Output and save the three-dimensional contour of the obtained karst cave reservoir model as a 3D printing digital model file in STL file format.

[0014] Preferably, in step S2, the steps of generating the orthogonal grid model include:

[0015] S2-1. Since the seismic data is based on a regularly distributed dot matrix, first calculate the step sizes along the three main directions of the three-dimensional dot matrix:

[0016]

[0017]

[0018]

[0019] Among them, P(i, j) represents the planar coordinates of the seismic gather with Inline number i and Xline number j, and Sample(i, j, k) represents the depth of the k-th point on the seismic gather;

[0020] S2-2. Take the coordinates of each seismic data point as the center point P C (i, j, k) of the grid cell, and establish an orthogonal grid model according to the step lengths in three main directions and The number of grids of the orthogonal grid model in three dimensions is: N Inline ×N Xline ×N Sample ;

[0021] S2-3. Assign the seismic attribute data of each seismic data point to the corresponding grid cell as the attribute of the grid cell.

[0022] Preferably, in step S2-2, after establishing the orthogonal grid model, for any grid (i, j, k) among them, the coordinates of its 8 vertices are:

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031] Preferably, the specific steps to obtain the contour of the karst cave characterized by triangular meshes in step S3 include:

[0032] S3-1. Select a certain seismic attribute data of the grid cell, and set the karst cave threshold value A according to the difference between the seismic attribute data of the karst cave and the formation. C , compare the selected seismic attribute data of each grid cell with the karst cave threshold value A C , screen the grid cells that reach the karst cave threshold value A C , and mark them as active grid cells, and mark the remaining grid cells as inactive grid cells;

[0033] S3-2. Set any active grid as the target active grid, search for the faces adjacent to the target active grid and non-active grids, and mark the adjacent faces of the target active grid and non-active grids as boundary faces. According to the positional relationship between the boundary faces and the coordinates of the grid cells (i, j, k), mark each boundary face as i-, i+, j-, j+, k- and k+ respectively.

[0034] S3-3. Traverse all active grids to obtain all adjacent faces, and then perform triangulation on the adjacent faces to obtain a karst cave contour represented by triangular meshes.

[0035] Preferably, between step S3 and step S4, optimize the karst cave contour to achieve a smooth transition of the surface shape. The method for optimizing the karst cave contour includes:

[0036] A1. Name the eight vertices of the active grid as P1 to P8 in sequence, and initialize the adjacent point set of the karst cave boundary surface. Then, for any point P, the adjacent point set includes all points that form a contour line with point P, denoted as Adj(P).

[0037] A2. Obtain the weight function ω of any adjacent point P of point P i of, and the weight function ω i adopts a Laplace smoothing function based on curvature: i In the two triangular meshes formed by the connection of P

[0038]

[0039] and P, α and β are the angles opposite to the connection line of P i and P in the two triangular meshes respectively; i and P connection line;

[0040] A3. For any vertex P in the point structure set S, obtain the adjacent point set Adj(P) of this vertex P. Assume that there are n points in the point set, and find the temporary point P * :

[0041]

[0042] Subsequently, assign the calculated P * to point P;

[0043] A4. Perform the above operations on all vertices to complete the smoothing operation;

[0044] Preferably, when optimizing the karst cave contour, repeat steps A1 to A4 at least twice.

[0045] Preferably, for any adjacent face obtained in step S3-3, assume that the coordinates of its four vertices are {P fi1 , Ffi2 , P fi3 , P fi4}, and the two triangular patches obtained after triangulating the adjacent surfaces respectively have three vertices. The vertex coordinates of the two triangular patches are respectively represented as f i1 = {P fi1 , P fi2 , F fi4} and f i2 = {F fi1 , P fi3 , F fi4}.

[0046] Preferably, in the STL file obtained in step S4, the STL file includes the geometric information of each triangular patch given line by line, and each line starts with a keyword associated with the geometric information of that line. The information unit facet of the triangular patch in the STL file is a triangular patch with a vector direction.

[0047] A computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, they are used to implement the above method for generating a 3D printing digital model of a karst cave.

[0048] A computer device includes a processor and a memory. The memory stores a computer program, and the computer program is loaded and executed by the processor to implement the above method for generating a 3D printing digital model of a karst cave.

[0049] The beneficial technical effects of the technical solution of the present invention are as follows:

[0050] (1) In this solution, an STL model is constructed by identifying and parsing SEGY format seismic data files. An orthogonal grid model is generated based on the coordinates of the parsed seismic data points, and the seismic attribute data of each data point is respectively assigned to each grid. Subsequently, by comparing the seismic attribute data of each grid, active grids and inactive grids, that is, the grid cells where karst caves are located, can be screened out. Then, by organizing the adjacent surfaces of the active grids and inactive grids, the overall contour of the karst cave can be obtained. The contour matches the actual contour. After saving it as an STL format 3D printing digital model file according to the STL file format, an accurate 3D printing digital model file can be obtained, providing a tool for the smooth development of 3D printing physical models, simplifying the steps of generating a 3D printing digital model of a karst cave, and providing a new tool for the smooth development of 3D printing physical models, with simple operation and low cost.

[0051] (2) Before outputting the three-dimensional contour of the karst reservoir model in the STL file format, optimize the karst contour to achieve a smooth transition of the surface shape, which can better match the contour of the real karst cave, improve the generation accuracy of the 3D printing digital model of the karst cave model, and further help improve the accuracy of the 3D printing physical model experiment. Description of the Drawings

[0052] Figure 1 The flowchart of the method for generating a 3D printing digital model of a karst cave in an embodiment of the present invention is shown;

[0053] Figure 2 The example diagram of the file header information of the SEGY format file in an embodiment of the present invention is shown;

[0054] Figure 3 The schematic diagram of the seismic data dot matrix step size in an embodiment of the present invention is shown;

[0055] Figure 4 The schematic diagram of the position of the active grid and its adjacent non-active grids in an embodiment of the present invention is shown;

[0056] Figure 5 The schematic diagram of the triangular division of the boundary surface in an embodiment of the present invention is shown;

[0057] Figure 6 The schematic diagram of point P and its adjacent point set in an embodiment of the present invention is shown;

[0058] Figure 7 The schematic diagram of the positional relationship between α, β and point P in an embodiment of the present invention is shown;

[0059] Figure 8 The diagram of the positional relationship between point P* and point P during the smoothing operation in an embodiment of the present invention is shown;

[0060] Figure 9 The schematic diagram of the seismic data volume of the fracture-vug reservoir in an embodiment of the present invention is shown;

[0061] Figure 10 The schematic diagram of the processed orthogonal grid and attributes in an embodiment of the present invention is shown;

[0062] Figure 11 The schematic diagram of extracting part of the karst cave grid in an embodiment of the present invention is shown;

[0063] Figure 12 The schematic diagram of constructing the three-dimensional contour of the karst cave model in an embodiment of the present invention is shown;

[0064] Figure 13 The schematic diagram of optimizing the three-dimensional contour in an embodiment of the present invention is shown;

[0065] Figure 14The figure shows the comparison diagram between the karst cave model extracted in the embodiment of the present invention and seismic data;

[0066] Figure 15 The figure shows the schematic diagram of the 3D printed digital model in the embodiment of the present invention. Detailed implementation manners

[0067] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further elaborates in detail on the method, storage medium and device for generating a 3D printed digital model of a karst cave proposed by the present invention in combination with the accompanying drawings and specific implementation manners. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are in a very simplified form and all use non-precise scales, only for the purpose of facilitating and clearly assisting in explaining the objectives of the implementation manners of the present invention. In order to make the objectives, features and advantages of the present invention more obvious and understandable, please refer to the accompanying drawings. It should be noted that the structures, scales, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have any technical substance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the objectives that can be achieved, should still fall within the scope covered by the technical content disclosed by the present invention.

[0068] The following will combine the attached Figures 1 to 15 and specific embodiments to elaborate in detail on the technical solutions of a method, storage medium and device for generating a 3D printed digital model of a karst cave of the present invention.

[0069] Embodiment

[0070] As Figures 1 to 15 shown, a method for generating a 3D printed digital model of a karst cave in this embodiment includes the following steps:

[0071] S1. Analyze the SEGY format seismic data file, read the seismic data information including the X and Y coordinates, common depth point (CDP) and seismic attribute data of the specified main survey line seismic interpretation profile (Inline) and cross-line seismic interpretation profile (Xline), determine each seismic data point with (Inline, Xline) as the index, and store the seismic data information corresponding to each seismic data point respectively.

[0072] The first 3200-byte file header of the SEGY file contains the text information of 40 records, each record consisting of 80 bytes of characters, providing an information description for directly reading the seismic data of this line in the SEGY file.

[0073] Since there is no fixed format standard for the file header information, the SEGY files obtained by different seismic acquisition and processing software may contain different information. Therefore, it is necessary to first read and interpret the information therein, including the storage locations of information such as Inline, Xline, X coordinate, Y coordinate, etc. In addition, the seismic attribute data referred to in this embodiment may include one or more of test information such as amplitude, frequency, phase, energy, waveform, wave impedance, and wave velocity.

[0074] S2. Generate a grid based on the X and Y coordinates of each seismic data point to obtain an orthogonal grid model, and respectively associate the seismic data information of each seismic data point with the corresponding grid. The specific steps are as follows:

[0075] S2-1. Since the seismic data is based on a regular distribution lattice, first confirm the step sizes along the three main directions of the three-dimensional lattice:

[0076]

[0077]

[0078]

[0079] Among them, P(i, j) represents the planar coordinates of the trace gather with Inline number i and Xline number j, Sample(i, j, k) represents the depth of the k-th point on the trace gather, and the resolution along the longitudinal direction is consistent, that is, the step vector can be calculated using 1 and 0

[0080] S2-2. Take the coordinates of each seismic data point as the center point P C (i, j, k) of the grid unit, and establish an orthogonal grid model according to the step sizes and along the three main directions. The number of grids of the orthogonal grid model in the three dimensions is: N Inline ×N Xline ×N Sample , after establishing the orthogonal grid model in this step, for any grid (i, j, k) therein, its 8 vertex coordinates are:

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089] S2-3. Assign the seismic attribute data of each seismic data point to the corresponding grid cells as the attributes of the grid cells, and record the attribute name as Amplitude.

[0090] S3. Search for similar connected regions according to the orthogonal grid model and the seismic data information of each grid cell to extract the solution caves in the orthogonal grid model. Then identify all the boundary surfaces of each grid that participate in forming the boundary of the solution cave, and perform triangulation on the boundary surfaces to obtain the solution cave contour represented by triangular meshes. The specific method includes:

[0091] S3-1. Select a certain seismic attribute data of the grid cell, and set the solution cave threshold A according to the difference between the seismic attribute data in the solution cave and the formation. C , compare the selected seismic attribute data of each grid cell with the solution cave threshold A C , and screen out the grid cells that reach the solution cave threshold A C , record them as ACTNUM = 1, and mark the remaining grid points as inactive grids, denoted as ACTNUM = 0;

[0092] S3-2. Set any active grid as the target active grid, search for the adjacent faces of the target active grid and the inactive grids, and mark the adjacent faces of the target active grid and the inactive grids as boundary surfaces. According to the position relationship between the boundary surfaces and the coordinates of the grid cell (i, j, k) where they are located, mark each boundary surface as i-, i+, j-, j+, k- and k+ respectively;

[0093] S3-3. Traverse all active grids to obtain all adjacent faces, and then obtain the solution cave contour represented by triangular meshes.

[0094] After completing step S3, the obtained solution cave contours are mostly "stepped" or "angular". The solution cave contours should be optimized to achieve a smooth transition of the curved surface shape, making the solution cave contours more approximate to the actual solution caves. The specific steps include:

[0095] A1. Name the eight vertices of the active grid as P1 to P8 in sequence, and initialize the adjacent point set of the solution cave boundary surface. Then for any point P, the adjacent point set includes all the points that form the contour line together with point P, denoted as Adj(P);

[0096] A2. Calculate the weight function ω of any adjacent point P i of point P i, different weight functions correspond to different smoothing algorithms. Here, a Laplace smoothing function based on curvature is adopted. Compared with the central smoothing function, it can ensure that the original geometric shape can still be roughly maintained after multiple iterations of smoothing:

[0097]

[0098] In the two triangular meshes formed by the connection of P i and P, α and β are the angles opposite to the connection line of P i in the two triangular meshes respectively;

[0099] A3. For any vertex P in the point structure set S, obtain the adjacent point set Adj(P) of this vertex P. Assume that there are n points in the point set, and find the temporary point P * :

[0100]

[0101] Subsequently, assign the calculated P * to the point P;

[0102] A4. Repeat the above operations for all vertices, and then a smoothing operation can be completed;

[0103] A5. Repeat steps A1 to A4 at least twice.

[0104] S4. Output the three-dimensional contour of the obtained karst reservoir model in the STL file format and save it as a 3D printing digital model file.

[0105] In the STL file of the 3D printing digital model, the STL file includes the geometric information of each triangular facet given line by line. Each line starts with 1 or 2 keywords. The information unit facet of the triangular facet in the STL file is a triangular facet with a vector direction.

[0106] The first line of the entire STL file gives the file path and file name. Moreover, each facet in the STL file consists of 7 lines of data. Facetnormal is the normal vector coordinates of the triangular facet pointing to the outside of the entity. Outerloop indicates that the subsequent 3 lines of data are the 3 vertex coordinates of the triangular facet respectively, and the 3 vertices are arranged counterclockwise along the normal vector direction pointing to the outside of the entity.

[0107] In this embodiment, an STL model is constructed by identifying and parsing SEGY format seismic data files. Then, an orthogonal grid model is generated based on the coordinates of the parsed seismic data points, and the seismic attribute data of each data point is assigned to each grid respectively. Subsequently, by analyzing and comparing the seismic attribute data of each grid, active grids, i.e., the grid cells where the karst caves are located, can be screened out. Then, by sorting out the adjacent surfaces of the active grids and the inactive grids, the overall contour of the karst cave can be obtained. The contour matches the actual contour. After saving it as an STL format 3D printing digital model file according to the STL file format, an accurate 3D printing digital model file can be obtained, providing a tool for the smooth implementation of 3D printing the physical model, simplifying the steps of generating the 3D printing digital model of the karst cave, providing a new tool for the smooth implementation of 3D printing the physical model, with simple operation and low cost.

[0108] In addition, this embodiment also discloses a computer-readable storage medium and a computer device. The computer-readable storage medium stores computer-executable instructions, which are used to implement the above method for generating a 3D printing digital model of a karst cave when executed by a processor. The computer device includes a processor and a memory. The memory stores a computer program, and the computer program is loaded and executed by the processor to implement the above method for generating a 3D printing digital model of a karst cave.

[0109] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0110] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be subject to the appended claims.

Claims

1. A method for generating a 3D printed digital model of a karst cave, characterized in that, Including the following steps: S1. Parse the SEGY format seismic data file, read the seismic data information including the X and Y coordinates, CDP (Common Depth Point) and seismic attribute data of the specified main survey line seismic interpretation profile (Inline) and cross-line seismic interpretation profile (Xline), determine each seismic data point with (Inline, Xline) as the index, and store the seismic data information corresponding to each seismic data point separately; S2. Generate a grid based on the X and Y coordinates of each seismic data point to obtain an orthogonal grid model, and associate the seismic data information of each seismic data point with the corresponding grid respectively; S3. Search for similar connected regions according to the orthogonal grid model and the seismic data information of each grid cell to extract the karst caves in the orthogonal grid model, then identify all the boundary surfaces of each grid participating in the formation of the karst cave boundary, and perform triangulation on the boundary surfaces to obtain the karst cave contour represented by triangular meshes; S4. Output and save the three-dimensional contour of the obtained karst cave reservoir model in the STL file format as a 3D printing digital model file.

2. A method for generating a 3D printed digital model of a karst cave as described in claim 1, characterized in that, In step S2, the steps of generating the orthogonal grid model include: S2-1. Since the seismic data is based on a regular distribution lattice, first calculate the step sizes along the three main directions of the three-dimensional lattice: Where P(i,j) represents the planar coordinates of the CDP with Inline number i and Xline number j, and Sample(i,j,k) represents the depth of the k-th point on the CDP; S2-2. Take the coordinates of each seismic data point as the center point P of the grid cell C (i, j, k), and establish an orthogonal grid model according to the step sizes in the three main directions and . The number of grids of the orthogonal grid model in the three dimensions is: N Inline ×N Xline ×N Sample ; S2-3. Assign the seismic attribute data of each seismic data point to the corresponding grid cell as the attribute of the grid cell.

3. A method for generating a 3D printed digital model of a karst cave as described in claim 2, characterized in that, In step S2-2, after establishing the orthogonal grid model, for any grid (i,j,k) among them, its eight vertex coordinates are:

4. A method for generating a 3D printed digital model of a karst cave as described in claim 2, characterized in that, The specific steps of obtaining the karst cave contour represented by triangular meshes in step S3 include: S3-1. Select a certain seismic attribute data of the grid unit, and set the karst cave threshold value A according to the difference between the seismic attribute data of the karst cave and the formation C , and compare the seismic attribute data selected from each grid unit with the karst cave threshold value A C , screen the grid units that reach the karst cave threshold value A C , and mark them as active grid units, and mark the remaining grid units as inactive grid units; S3-2. Set any active grid as the target active grid, search for the faces adjacent to the target active grid and non-active grids, and mark the adjacent faces of the target active grid and non-active grids as boundary surfaces. According to the position relationship between the boundary surfaces and the coordinates of the grid cell (i,j,k) where they are located, mark each boundary surface as i-, i+, j-, j+, k- and k+ respectively; S3-3. Traverse all active grids to obtain all adjacent faces, and then perform triangulation on the adjacent faces to obtain the karst cave contour represented by triangular meshes.

5. A method for generating a 3D printed digital model of a karst cave as described in claim 4, characterized in that, Between step S3 and step S4, optimize the karst cave contour to achieve a smooth transition of the surface shape. The method for optimizing the karst cave contour includes: A1. Name the eight vertices of the active grid as P1 to P8 in sequence, and initialize the adjacent point set of the karst cave boundary surface. Then for any point P, the adjacent point set includes all the points that form the contour line with point P, denoted as Adj(P); A2. Obtain any adjacent point P of point P i with weight function ω i wherein the weight function ω i adopts a Laplace smoothing function based on curvature: At P i In the two triangular meshes formed by the connection lines with P, α and β are respectively the angles opposite to P in the two triangular meshes i in the connection lines with P; A3. For any vertex P in the point structure set S, obtain the adjacent point set Adj(P) of this vertex P. Assume there are n points in the point set, and find the temporary point P * : Subsequently, assign the calculated P * to point P; A4. Perform the above operations on all vertices to complete the smoothing operation.

6. A method for generating a 3D printed digital model of a karst cave as described in claim 5, characterized in that, When optimizing the karst cave contour, repeat steps A1 to A4 at least twice.

7. A method for generating a 3D printed digital model of a karst cave as described in claim 4, characterized in that, For any adjacent face obtained in step S3-3, assume that the coordinates of its four vertices are {P fi1 , P fi2 , P fi3 , P fi4}. After triangulating the adjacent face, the two triangular patches obtained each have three vertices. The vertex coordinates of the two triangular patches are respectively represented as f i1 = {P fi1 , P fi2 , P fi4} and f i2 = {P fi1 , P fi3 , P fi4}.

8. A method for generating a 3D printed digital model of a karst cave as described in claim 7, characterized in that, In the STL file obtained in step S4, the STL file includes geometric information of each triangular facet given line by line, and keywords associated with the geometric information of each line are noted at the beginning of each line. The information unit facet of the triangular facets in the STL file is a triangular facet with a vector direction.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which are used to implement the method for generating a 3D printed digital model of a karst cave as described in any one of claims 1 to 8 when executed by a processor.

10. A computer device, characterized in that, The computer device includes a processor and a memory. The memory stores a computer program, and the computer program is loaded and executed by the processor to implement the method for generating a 3D printed digital model of a karst cave as described in any one of claims 1 to 8.

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