Fusion method of BIM design terrain and GIS live-action texture

Abstract

The invention relates to the field of BIM model visualization, in particular to a BIM design terrain and GIS live-action texture fusion method, BIM design terrain and GIS live-action texture data are processed respectively, when GIS live-action texture data changes, data updating can be achieved only by replacing slice data, and the convenience of data updating is improved; according to the method, the relation between the image slice nodes of the GIS live-action texture data and the space coordinates of the BIM design terrain is established through the coordinate system transformation matrix, so that coordinate transformation between the image slice nodes and the space coordinates of the BIM design terrain is facilitated, the space coordinates of the BIM design terrain correspond to the texture coordinates of the GIS live-action texture data, and finally fusion of the BIM design terrain and the GIS live-action texture data is realized.

Description

Technical Field

[0001] This invention relates to the field of BIM model visualization, specifically to a method for fusing BIM-designed terrain with GIS real-world textures. Background Technology

[0002] BIM-designed terrain refers to a precise 3D terrain model created and managed in professional BIM design software. Through terrain editing and analysis, it enables accurate, efficient, and sustainable applications in road and route design, drainage system design, building and terrain integration, visualization, and digital delivery. GIS real-world textures can be acquired through aerial photography, satellite remote sensing, UAV photography, or laser scanning, and used to visualize real-world surface spatial information, including raster images, vector maps, and oblique photogrammetry.

[0003] Because BIM-designed terrain is generally a single-precision mesh model without texture information, there is a problem of missing real-world texture information within the design terrain's representation range when fused with multi-source heterogeneous reality models such as terrain imagery and oblique photogrammetry. This reduces the visualization effect of digital application scenarios. Since real-world textures have high resolution and large volume, directly applying textures to the design terrain would place a significant burden on model loading and rendering. Furthermore, using traditional methods of repeating single-texture mapping cannot fully reflect the true real-world texture information, offering little improvement in visualization. During geometric processing such as editing, analysis, and design, the designed terrain will exhibit noticeable slope changes.

[0004] Existing technologies primarily employ two methods: one is to use orthophotos for vertical projection mapping, which can lead to significant texture stretching and distortion in areas with large slopes or vertical sections; the other is to fuse the designed terrain with LOD (Level of Detail) real-world textures. This method involves segmenting, grading, and simplifying the designed terrain, referencing the LOD real-world texture generation organization. While this approach can solve the loading and rendering problems of large-scale real-world textures, it alters the original geometric structure of the designed terrain and creates geometric information redundancy, posing challenges to analysis and applications based on the designed terrain. Furthermore, existing technologies do not address the integration of BIM designed terrain with online electronic maps and oblique photogrammetric textures, nor do they solve the updating issues of GIS real-world textures.

[0005] In view of this, there is an urgent need for a method to integrate BIM-designed terrain with GIS real-world textures in order to alleviate or even solve the above problems. Summary of the Invention

[0006] The main objective of this invention is to provide a method for fusing BIM-designed terrain with GIS real-world textures, in order to solve the technical problems of large texture deformation and easy alteration of geometric information when fusing BIM-designed terrain with GIS real-world textures in the prior art.

[0007] To achieve the above objectives, this invention provides a method for fusing BIM-designed terrain with GIS real-world textures, comprising the following steps: S1. Obtain the triangular mesh model M and angle threshold of the BIM-designed terrain. According to the angle threshold The triangular mesh model M is divided into n projection directions D. i The triangular mesh model M i Where 0 ≤ i < n, and i is a positive integer; S2. Acquire GIS real-scene texture data and the WMTS standard; process the GIS real-scene texture data according to the WMTS standard to obtain multi-resolution image tile data W. i Among them, slice data W i The number of levels is l, and the slice side length is e; S3. Determine the triangular mesh model M. i Is it empty and slice data W? i Is it empty; if the triangular mesh model M i and slice data W i If none of them are empty, proceed to step S4; S4. Obtain the coordinate system transformation matrix and slice data W i Image slice node W in layer l ijk According to the projection direction D i Image slice node W ijk Coordinate transformation to triangular mesh model M i The coordinates in the coordinate system; where 0 ≤ j ≤ n k k is the level of the image slice node, n k The number of nodes in the image slice; S5, Based on the slice data W i Along the projection direction D i The triangular mesh model M i The mesh is divided into sub-triangular meshes, resulting in model C. ij ; S6, Traversal C ij For each vertex P, the projected coordinates of vertex P are obtained according to the coordinate system transformation matrix. Based on the projected coordinates of vertex P, the position of vertex P in the slice data W is determined. i The corresponding texture coordinates are used to ultimately achieve the fusion of BIM-designed terrain and GIS real-world texture data.

[0008] Furthermore, step S1 specifically includes the following steps: By traversing all the triangular faces of the triangular mesh model M, the angle between the normal and the horizontal direction of each triangular face is obtained. The angle between the normal and the positive X-axis According to the angle threshold Angle and included angle The triangular mesh model M is divided into n projection directions D. i The triangular mesh model M i .

[0009] Further, the step of using the angle threshold Angle and included angle The triangular mesh model M is divided into n projection directions D. i The triangular mesh model M i Specifically, it includes the following steps: Extract all > The triangular facets form a triangular mesh model M0; extract and or The triangular facets form a triangular mesh model M1; extract and The triangular facets form a triangular mesh model M2; extract and The triangular facets form a triangular mesh model M3; extract and The triangular facets form a triangular mesh model M4; wherein, the projection direction D0 of the triangular mesh model M0 is the positive Z-axis, the projection direction D1 of the triangular mesh model M1 is the positive X-axis, the projection direction D2 of the triangular mesh model M2 is the negative Y-axis, the projection direction D3 of the triangular mesh model M3 is the negative X-axis, and the projection direction D4 of the triangular mesh model M4 is the positive Y-axis.

[0010] Furthermore, step S1 also includes the following steps: Obtain the BIM design terrain and determine whether the geographic coordinate system information contained in the BIM design terrain is correct. If it is correct, parse the BIM design terrain into a triangular mesh model M. If it is incorrect, first correct the geographic coordinate system information, and then parse the BIM design terrain into a triangular mesh model M.

[0011] Furthermore, step S2 also includes the following steps: For GIS real-scene texture data in the form of oblique photogrammetry: acquire the oblique photogrammetry model, extract the precision 'a' and the triangular mesh model 'M'. i Perpendicular to the projection direction D i The range of plane coordinate values ​​is used to construct raster data; Obtain the center point of each raster cell in the raster data, and construct a projection line D parallel to the projection direction using the center point. i The lowest intersection point between the ray and the oblique photography model is obtained; Obtain the RGB value of the lowest intersection point, and assign the RGB value of the lowest intersection point to the raster unit corresponding to the ray, thereby obtaining GIS real-scene texture data in the form of a raster image.

[0012] Furthermore, obtaining the coordinate system transformation matrix in step S4 specifically includes the following steps: Get slice data W i The coordinates of the top left corner are Resolution a k and slice data W i The index in is Thus, slice data W is obtained. i The coordinates of each pixel in the image are: Thus, the coordinate system transformation matrix is ​​determined: Projection direction D i Corresponding spatial coordinates .

[0013] Furthermore, step S6 specifically includes the following steps: Get slice data W i top left corner coordinates traversing C ij For each vertex P, the projected coordinates of vertex P are obtained according to the coordinate system transformation matrix. Using formula Obtain vertex P in slice data W i The corresponding texture coordinates Ultimately, this will achieve the fusion of BIM-designed terrain and GIS real-world texture data.

[0014] More preferably, after step S6, the following steps are also included: Subtriangular mesh model C ij Save as a new triangular mesh model MS i Obtain the sub-triangular mesh model C ij Corresponding slice data W i Texture coordinate results for each layer (UV) ijk ; Get slice data W i The file storage path for the sliced ​​data Wi File storage path and texture coordinate results UV ijk With sub-triangular mesh model C ij Establish the association, then input the triangular mesh model MS. i In the material and geometric structure data.

[0015] More preferably, the method further includes the following steps: Obtain the triangular mesh model MS i The file storage path is used to determine the triangular mesh model MS. i and slice data W i Are the file storage paths of the two the same? If not, then use the triangular mesh model MS. i Stored to the slice data W i Using the same file directory, construct and generate a triangular mesh model MS. i The JSON index file is used to obtain the final fusion result.

[0016] More preferably, the method further includes the following steps: Obtain the current GIS real-scene texture data and determine whether the current GIS real-scene texture data has changed; if so, return to step S2 to process the current GIS real-scene texture data and obtain the tile data W of the current multi-resolution image. d The slice data W in step S2 i Replace with W d Proceed to step S3.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention processes BIM-designed terrain and GIS real-world texture data separately. When the GIS real-world texture data changes, data updates can be achieved simply by replacing the tile data, improving the convenience of data updates. This invention establishes a connection between the image tile nodes of the GIS real-world texture data and the spatial coordinates of the BIM-designed terrain through a coordinate system transformation matrix, facilitating coordinate transformation between the two. This allows the spatial coordinates of the BIM-designed terrain to correspond with the texture coordinates of the GIS real-world texture data, ultimately achieving the fusion of BIM-designed terrain and GIS real-world texture data. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating a method for fusing BIM-designed terrain with GIS real-world textures in one embodiment of the present invention.

[0020] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0024] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0025] Please see Figure 1 This embodiment provides a method for fusing BIM-designed terrain with GIS real-world textures, including the following steps: S1. Obtain the triangular mesh model M and angle threshold of the BIM-designed terrain. According to the angle threshold The triangular mesh model M is divided into n projection directions D. i The triangular mesh model M i Where 0 ≤ i < n, and i is a positive integer.

[0026] Specifically, the BIM design terrain is acquired, and the accuracy of the geographic coordinate system information contained within it is determined. If correct, the BIM design terrain is parsed into a triangular mesh model M. If incorrect, the geographic coordinate system information is corrected before parsing the BIM design terrain into a triangular mesh model M. Each design platform's BIM model can be parsed using its own tools or secondary development interfaces. For example, the Bentley platform can achieve accurate and complete parsing of BIM model-related information based on MDL development.

[0027] By traversing all the triangular faces of the triangular mesh model M, the angle between the normal and the horizontal direction of each triangular face is obtained. The angle between the normal and the positive X-axis ; where the included angle Take the positive value counterclockwise, the included angle Take the positive value of the acute angle and the slope. The relationship between them is: According to the angle threshold Angle and included angle The triangular mesh model M is divided into 5 parts with projection directions D. i The triangular mesh model M i Extract all > The triangular facets form a triangular mesh model M0; extract and or The triangular facets form a triangular mesh model M1; extract and The triangular facets form a triangular mesh model M2; extract and The triangular facets form a triangular mesh model M3; extract and The triangular facets form a triangular mesh model M4; wherein, the projection direction D0 of the triangular mesh model M0 is the positive Z-axis, the projection direction D1 of the triangular mesh model M1 is the positive X-axis, the projection direction D2 of the triangular mesh model M2 is the negative Y-axis, the projection direction D3 of the triangular mesh model M3 is the negative X-axis, and the projection direction D4 of the triangular mesh model M4 is the positive Y-axis.

[0028] S2. Acquire GIS real-scene texture data and the WMTS standard; process the GIS real-scene texture data according to the WMTS standard to obtain multi-resolution image tile data W. i .

[0029] GIS real-world texture data includes various formats such as raster images, vector maps, and oblique photogrammetry. Raster and vector map forms of GIS real-world texture data can be directly tiled using the WMTS standard. However, current technologies struggle to integrate oblique photogrammetry-based GIS real-world texture data with BIM-designed terrain.

[0030] In this embodiment, for GIS real-scene texture data in the form of oblique photogrammetry: Oblique photogrammetry model is acquired, and the extraction precision 'a' and triangular mesh model 'M' are performed. i Perpendicular to the projection direction D i The range of plane coordinate values ​​is used to create raster data with a resolution of a, a width of w, a height of h, and 4 bands based on the GDAL library; wherein the range of plane coordinate values ​​is a rectangular range with a length of w and a width of h. Obtain the center point of each raster cell in the raster data, and construct a projection line D parallel to the projection direction using the center point. i The lowest intersection point between the ray and the oblique photography model is obtained; The RGB value of the lowest intersection point is obtained, and the RGB value of the lowest intersection point is assigned to the raster unit corresponding to the ray, thereby obtaining GIS real-scene texture data in the form of a raster image, which facilitates processing by the WMTS standard.

[0031] It is worth noting that for GIS real-world texture data in the form of raster images that do not conform to the WMTS standard set by OGC, third-party software or tools, such as CesiumLab, Cesium Terrain Builder, SuperMap, and ArcGIS, can be directly processed into WMTS-compliant tile data W0; wherein, the tile data W0 corresponds to the triangular mesh model M0 of the projection direction D0 in step 2.

[0032] S3. Determine the triangular mesh model M. i Is it empty and slice data W? i Is it empty; if the triangular mesh model M i and slice data W i If none of them are empty, proceed to step S4.

[0033] S4. Obtain the coordinate system transformation matrix and slice data W i Image slice node W in layer l ijk According to the projection direction D i The image slice node W is transformed using the coordinate system transformation matrix. ijk Coordinate transformation to triangular mesh model M i The coordinates in the coordinate system; where 0 ≤ j ≤ n k k is the level of the image slice node, nk The number of image tile nodes, and the tile data W. i The number of levels is l, and the slice data is W. i The side length of the slice is e.

[0034] Specifically, obtain slice data W i The coordinates of the top left corner are Resolution a k and slice data W i The index in is Thus, slice data W is obtained. i The coordinates of each pixel in the image are: Thus, the coordinate system transformation matrix is ​​determined: Projection direction D i Corresponding spatial coordinates .

[0035] Traversing C ij For each vertex P, the projected coordinates of vertex P are obtained according to the coordinate system transformation matrix. Using formula Obtain vertex P in slice data W i The corresponding texture coordinates Ultimately, this will achieve the fusion of BIM-designed terrain and GIS real-world texture data.

[0036] S5, Based on the slice data W i Along the projection direction D i The triangular mesh model M i The mesh is divided into sub-triangular meshes, resulting in model C. ij .

[0037] S6, Traversing Subtriangular Mesh Model C ij For each vertex P, the projected coordinates of vertex P are obtained according to the coordinate system transformation matrix. Based on the projected coordinates of vertex P, the position of vertex P in the slice data W is determined. i The corresponding texture coordinates are used to ultimately achieve the fusion of BIM-designed terrain and GIS real-world texture data.

[0038] In one embodiment, the sub-triangular mesh model C ij Save as a new triangular mesh model MS i Obtain the sub-triangular mesh model C ij Corresponding slice data W i Texture coordinate results for each layer (UV) ijk ; Get slice data W i The file storage path for the sliced ​​data W i File storage path and texture coordinate results UV ijkWith sub-triangular mesh model C ij Establish the association, then input the triangular mesh model MS. i In the material and geometric structure data.

[0039] Obtain the triangular mesh model MS i The file storage path is used to determine the triangular mesh model MS. i and slice data W i Are the file storage paths of the two the same? If not, then use the triangular mesh model MS. i Stored to the slice data W i Using the same file directory, construct and generate a triangular mesh model MS. i The JSON index file is used to obtain the final fusion result.

[0040] Obtain the current GIS real-scene texture data and determine whether the current GIS real-scene texture data has changed; if so, return to step S2 to process the current GIS real-scene texture data and obtain the tile data W of the current multi-resolution image. d The slice data W in step S2 i Replace with W d Proceed to step S3.

[0041] The method described in this embodiment supports the fusion processing of multi-source GIS real-world textures, including raster images, vector maps, and oblique photography. This method applies slope to the processing of BIM-designed terrain and GIS real-world textures, improving the fusion visualization effect. It separates and stores geometric files and texture files, providing a convenient and effective update mechanism for GIS real-world textures. The method uses a combination of single-precision triangular mesh models and multi-resolution textures for data organization, improving loading and rendering efficiency. This method only cuts the BIM-designed terrain; coordinates, positions, and geometric shapes remain unchanged, satisfying the requirements for accurate analysis and application based on BIM-designed terrain.

[0042] Example: Using the Bentley platform MicroStation Connect Edition Update 16 and MicroStationCONNECT Edition SDK for secondary development, the BIM design terrain results of a certain project were parsed into a triangular mesh model and output as an OBJ file. The parsed geographic coordinate system information is CGCS2000 / 3-degree Gauss-Kruger CM 108E (EPSG:4545).

[0043] The angle threshold is set to 0°. By calculating and determining the range of angles between the normal of each triangular facet and the horizontal plane and the X-axis, the OBJ model is divided into two triangular meshes, A and B, with projection directions of positive and negative axes, respectively. The extraction precision of the oblique photogrammetry was set to 10cm. The projection ranges of A and B were calculated, and TIFF raster R were created based on the GDAL library. A and R B Furthermore, it combines oblique photogrammetry to calculate and store the value of each raster unit.

[0044] Using the image tiling function of CesiumLab software (version 3.1), the service type was set to WMTS, the tile size to 256, and the R image was tiled according to the Mercator projection method. A and R B The process yielded image tiling results at six different levels. and (Since slices at levels 15 and below have only a single node, slice results at levels 0 to 14 are deleted, and only slice data at levels 15 to 20 (a total of 6 levels) are retained.) Traverse each and The sixth level raster slice result, according to the WMTS encoding rules, calculates the coordinate range of a single slice. After coordinate transformation, it is cut from the axial direction and the axial direction respectively based on the CGAL library to obtain a new triangular mesh. and ; Calculate and update and Each subgrid corresponds to and The UV coordinates of the six-level image slices are calculated, and material information is constructed to store the relative path information of the slice texture; Construct a JSON index file containing the and , and organize the merged results.

[0045] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for fusing BIM-designed terrain with GIS real-world textures, characterized in that, Includes the following steps: S1. Obtain the triangular mesh model M and angle threshold of the BIM-designed terrain. According to the angle threshold The triangular mesh model M is divided into n projection directions D. i The triangular mesh model M i Where 0 ≤ i < n, and i is a positive integer; S2. Obtain GIS real-scene texture data and the WMTS standard. Based on the WMTS standard, slice the GIS real-scene texture data to obtain multi-resolution image slice data W. i ; S3. Determine the triangular mesh model M. i Whether it is empty, and to determine the slice data W i Is it empty; if the triangular mesh model M i and slice data W i If none of them are empty, proceed to step S4; S4. Obtain the coordinate system transformation matrix and slice data W i Image slice node W ijk According to the projection direction D i The image slice node W is transformed using the coordinate system transformation matrix. ijk Coordinate transformation to triangular mesh model M i The coordinates in the coordinate system; where 0 ≤ j ≤ n k k is the level of the image slice node, n k The number of nodes in the image slice; S5, Based on the slice data W i Along the projection direction D i The triangular mesh model M i The mesh is divided into sub-triangular meshes, resulting in model C. ij ; S6, Traversing Subtriangular Mesh Model C ij For each vertex P, the projected coordinates of vertex P are obtained according to the coordinate system transformation matrix. Based on the projected coordinates of vertex P, the position of vertex P in the slice data W is determined. i The corresponding texture coordinates are used to achieve the fusion of BIM-designed terrain and GIS real-world texture data.

2. The method for fusing BIM-designed terrain and GIS real-world textures according to claim 1, characterized in that, In step S1, the angle threshold is used as described. The triangular mesh model M is divided into n projection directions D. i The triangular mesh model M i Specifically, it includes the following steps: By traversing all the triangular faces of the triangular mesh model M, the angle between the normal and the horizontal direction of each triangular face is obtained. and the angle between the normal and the positive X-axis. According to the angle threshold Angle and included angle The triangular mesh model M is divided into n projection directions D. i The triangular mesh model M i .

3. The method for fusing BIM-designed terrain and GIS real-world textures according to claim 2, characterized in that, According to the angle threshold Angle and included angle The triangular mesh model M is divided into n projection directions D. i The triangular mesh model M i Specifically, it includes the following steps: Extract all > The triangular facets form a triangular mesh model M0; extract and or The triangular facets form a triangular mesh model M1; extract and The triangular facets form a triangular mesh model M2; extract and The triangular facets form a triangular mesh model M3; extract and The triangular facets form a triangular mesh model M4; wherein, the projection direction D0 of the triangular mesh model M0 is the positive Z-axis, the projection direction D1 of the triangular mesh model M1 is the positive X-axis, the projection direction D2 of the triangular mesh model M2 is the negative Y-axis, the projection direction D3 of the triangular mesh model M3 is the negative X-axis, and the projection direction D4 of the triangular mesh model M4 is the positive Y-axis.

4. The method for fusing BIM-designed terrain and GIS real-world textures according to claim 1, characterized in that, The step S1 of obtaining the triangular mesh model M of the BIM design terrain specifically includes the following steps: Obtain the BIM design terrain and determine whether the geographic coordinate system information contained in the BIM design terrain is correct; if yes, parse the BIM design terrain into a triangular mesh model M; if no, first correct the geographic coordinate system information, and then parse the BIM design terrain into a triangular mesh model M.

5. The method for fusing BIM-designed terrain and GIS real-world textures according to claim 1, characterized in that, For GIS real-scene texture data in the form of oblique photogrammetry, step S2 further includes the following steps: For GIS real-scene texture data in the form of oblique photogrammetry: acquire the oblique photogrammetry model, extract the precision 'a' and the triangular mesh model 'M'. i Perpendicular to the projection direction D i The range of plane coordinate values ​​is used to construct raster data; Obtain the center point of each raster cell in the raster data, and construct a projection line D parallel to the projection direction using the center point. i The lowest intersection point between the ray and the oblique photography model is obtained; Obtain the RGB value of the lowest intersection point, and assign the RGB value of the lowest intersection point to the raster unit corresponding to the ray, thereby obtaining GIS real-scene texture data in the form of a raster image.

6. The method for fusing BIM-designed terrain and GIS real-world textures according to claim 1, characterized in that, Step S4, which involves obtaining the coordinate system transformation matrix, specifically includes the following steps: Get slice data W i The coordinates of the top left corner are Resolution a k and slice data W i The index in is Thus, slice data W is obtained. i The coordinates of each pixel in the image are: Thus, the coordinate system transformation matrix is ​​determined: Projection direction D i Corresponding spatial coordinates .

7. The method for fusing BIM-designed terrain and GIS real-world textures according to claim 1, characterized in that, Step S6 specifically includes the following steps: Get slice data W i top left corner coordinates traversing C ij For each vertex P, the projected coordinates of vertex P are obtained according to the coordinate system transformation matrix. Using formula Obtain vertex P in slice data W i The corresponding texture coordinates Ultimately, this achieves the fusion of BIM-designed terrain and GIS real-world texture data; among which, the tile data W i The side length of the slice is e.

8. The method for fusing BIM-designed terrain and GIS real-world textures according to claim 7, characterized in that, Step S6 is followed by the following steps: Subtriangular mesh model C ij Save as a new triangular mesh model MS i Obtain the sub-triangular mesh model C ij Corresponding slice data W i Texture coordinate results for each layer (UV) ijk ; Get slice data W i The file storage path for the sliced ​​data W i File storage path and texture coordinate results UV ijk With sub-triangular mesh model C ij Establish the association, then input the triangular mesh model MS. i In the material and geometric structure data.

9. The method for fusing BIM-designed terrain and GIS real-world textures according to claim 8, characterized in that, Step S6 is followed by the following steps: Obtain the triangular mesh model MS i The file storage path is used to determine the triangular mesh model MS. i and slice data W i Are the file storage paths of the two the same? If not, then use the triangular mesh model MS. i Stored to the slice data W i Using the same file directory, construct and generate a triangular mesh model MS. i The JSON index file is used to obtain the final fusion result.

10. The method for fusing BIM-designed terrain and GIS real-world textures according to claim 1, characterized in that, Step S6 is followed by the following steps: Obtain the current GIS real-scene texture data and determine whether the current GIS real-scene texture data has changed; if so, return to step S2 to process the current GIS real-scene texture data and obtain the tile data W of the current multi-resolution image. d The slice data W in step S2 i Replace with W d Proceed to step S3.

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