A layered block three-dimensional model node merging method, device and electronic device

Abstract

This application relates to a method, apparatus, electronic device, and storage medium for merging nodes in a layered and segmented 3D model. The method includes obtaining the root nodes to be merged; determining the overall bounding box to be merged and its major axis, width axis, and height axis based on the root nodes; dividing the overall bounding box along the major and width axes to obtain segmented grids; obtaining the segmentation vertices formed by the segmented grids along the major and width axes; constructing a 3D mesh scene including a preset number of root nodes; extending vertex rays from the segmented vertices along the height axis; and determining the target multi-level of detail based on the segmented vertices, the 3D mesh scene, and the vertex rays, and merging the root nodes to be merged into the target level root nodes. This application solves the problem of maintaining rendering quality while reducing the number of nodes required to initially display the entire layered and segmented 3D model, improving the loading speed and display smoothness of layered and segmented 3D models such as oblique photogrammetry models.

Description

Technical Field

[0001] This application relates to the field of layered and segmented 3D models, and in particular to a method, apparatus, electronic device, and storage medium for merging nodes in a layered and segmented 3D model. Background Technology

[0002] Oblique photogrammetry is a cutting-edge technology that has emerged in the international surveying and mapping field in recent years. It overturns the limitations of traditional orthophotos, which can only be taken from a vertical angle. By mounting multiple sensors on the same flight platform, it simultaneously acquires images from five different angles—one vertical and four oblique—bringing users into a realistic and intuitive world that conforms to human vision. However, if the oblique photogrammetry area is large or the data volume is large, the initial display of the entire layered and segmented 3D model requires loading many nodes, resulting in slow loading speeds and choppy display. Current technologies also support merging root nodes in oblique photogrammetry, but this can only merge a limited number of levels, and the resulting new levels are coarse, with poor detail preservation and poor rendering quality.

[0003] Currently, no effective solution has been proposed for the problem of how to maintain rendering quality while reducing the number of nodes required to initially display the entire layered and segmented 3D model, such as an oblique photogrammetry model. Summary of the Invention

[0004] This application provides a method, apparatus, electronic device, and storage medium for merging nodes in a layered and segmented 3D model, to at least solve the problem in related technologies of how to maintain rendering quality while reducing the number of nodes required to initially display the entire layered and segmented 3D model, such as an oblique photogrammetry model.

[0005] In a first aspect, embodiments of this application provide a method for merging nodes in a hierarchical and block-based three-dimensional model.

[0006] In some embodiments, the method includes the following steps:

[0007] Obtain the root node to be merged, determine the bounding box of the root node to be merged, determine the overall bounding box to be merged based on the bounding box to be merged, and determine the major axis direction, width axis direction and height axis direction of the overall bounding box to be merged.

[0008] The bounding box to be merged is divided into segments along the major axis and the width axis to obtain segments. The segments formed by the segments along the major axis and the width axis are obtained. A three-dimensional mesh scene including a preset number of root nodes is constructed. Vertex rays emanating from the segments extend along the height axis.

[0009] Based on the segmented vertices, the 3D mesh scene, and the vertex rays, the target multi-level of detail is determined, and based on the target multi-level of detail, the root nodes to be merged are merged into the target level root nodes.

[0010] In some embodiments, determining the target multi-level of detail (MLD) based on the segmented vertices, the 3D mesh scene, and the vertex rays, and merging the root nodes to be merged into the target level root nodes based on the target MLD, includes:

[0011] Based on the segmented vertices, the 3D mesh scene, and the vertex rays, determine the lightweight mesh model and the diffuse texture of the lightweight mesh model;

[0012] The lightweight mesh model and the diffuse map are determined as the target multi-level of detail. Based on the target multi-level of detail, the root nodes to be merged are merged into the target level root nodes.

[0013] In some embodiments, determining the lightweight mesh model and the diffuse map of the lightweight mesh model based on the segmented vertices, the 3D mesh scene, and the vertex rays includes:

[0014] Based on the segmented vertices, the 3D mesh scene, and the vertex rays, determine the lightweight 3D mesh surface data and the lightweight 3D mesh vertex data;

[0015] Based on the lightweight 3D mesh vertex data, the corresponding UV coordinate data is determined, and based on the UV coordinate data, the lightweight mesh model is determined.

[0016] The lightweight mesh model is imported into the 3D mesh scene to obtain the diffuse texture of the lightweight mesh model.

[0017] In some embodiments, determining the lightweight 3D mesh surface data and lightweight 3D mesh vertex data based on the segmented vertices, the 3D mesh scene, and the vertex rays includes:

[0018] Obtain the three-dimensional intersection point formed by the intersection of the vertex ray and the three-dimensional mesh scene, and the three-dimensional intersection point formed by the intersection of the segmented vertex and the three-dimensional mesh scene. Connect two adjacent three-dimensional intersection points, and connect adjacent three-dimensional intersection points and the segmented vertex to obtain three-dimensional mesh surface data and three-dimensional mesh vertex data.

[0019] The three-dimensional mesh surface data and the three-dimensional mesh vertex data are reduced in size to determine lightweight three-dimensional mesh surface data and lightweight three-dimensional mesh vertex data.

[0020] In some embodiments, determining the target multi-level of detail (MLD) based on the segmented vertices, the 3D mesh scene, and the vertex rays, and merging the root nodes to be merged into the target level root nodes based on the target MLD, includes:

[0021] The target's multi-level of detail is determined based on the segmented vertices, the 3D mesh scene, and the vertex rays;

[0022] An initial target oblique photography file is created, and the 3D mesh model data and 3D mesh texture data corresponding to the multi-detail levels of the target are stored in the initial target oblique photography file to obtain a new level target oblique photography file. The new level target oblique photography file is determined as the root node of the target level.

[0023] In some embodiments, obtaining the root node to be merged, determining the bounding box of the root node to be merged, determining the overall bounding box to be merged based on the bounding box, and determining the major axis direction, width axis direction, and height axis direction of the overall bounding box to be merged include:

[0024] Obtain the root node to be merged, determine the bounding box of the root node to be merged, determine the overall bounding box to be merged based on the bounding box to be merged, and determine the major axis direction, width axis direction and height axis direction of the overall bounding box to be merged, wherein the thickness of the overall bounding box to be merged is the smallest in the height axis direction.

[0025] In some embodiments, obtaining the root node to be merged, determining the bounding box of the root node to be merged, determining the overall bounding box to be merged based on the bounding box, and determining the major axis direction, width axis direction, and height axis direction of the overall bounding box to be merged include:

[0026] Obtain the root node to be merged, determine the bounding box of the root node to be merged, and add all the bounding boxes to be merged to obtain the overall bounding box to be merged.

[0027] Determine the major axis, width axis, and height axis of the overall bounding box to be merged.

[0028] Secondly, embodiments of this application provide a device for merging nodes in a layered and segmented three-dimensional model.

[0029] In some embodiments, the device can be a tilted photogrammetry model node merging device, including a high-axis direction determination module, a vertex ray extension module, and a root node merging module:

[0030] The high axis direction determination module is used to obtain the root node to be merged, determine the bounding box to be merged of the root node to be merged, determine the overall bounding box to be merged based on the bounding box to be merged, and determine the major axis direction, width axis direction and high axis direction of the overall bounding box to be merged.

[0031] The vertex ray extension module is used to divide the bounding box to be merged into a segmented grid in the long axis direction and the wide axis direction to obtain the segmented vertices formed by the segmented grid in the long axis direction and the wide axis direction, construct a three-dimensional mesh scene including a preset number of root nodes, and extend vertex rays emanating from the segmented vertices along the high axis direction.

[0032] The root node merging module is used to determine the target multi-level of detail based on the segmented vertices, the 3D mesh scene, and the vertex rays, and to merge the root nodes to be merged into the target level root nodes based on the target multi-level of detail.

[0033] Thirdly, embodiments of this application provide an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the layered and block-based three-dimensional model node merging method as described in the first aspect above.

[0034] Fourthly, embodiments of this application provide a storage medium storing a computer program that, when executed by a processor, implements the layered and block-based 3D model node merging method described in the first aspect above.

[0035] Compared to related technologies, the present application provides a method, apparatus, electronic device, and storage medium for merging nodes in a layered and segmented 3D model. This method involves obtaining the root node to be merged, determining its bounding box, and then determining the overall bounding box to be merged along its major axis, width axis, and height axis. The overall bounding box is then divided along the major and width axes to obtain segmented grids. The segmented vertices formed by these grids along the major and width axes are obtained. A 3D mesh scene including a preset number of root nodes is constructed. Vertex rays emanating from the segmented vertices extend along the height axis. A target level of detail (MLD) is determined based on the segmented vertices, the 3D mesh scene, and the vertex rays. Finally, the root nodes to be merged are merged into the target level root node based on the target MLD. This solves the problem of maintaining rendering quality while reducing the number of nodes required to initially display the entire layered and segmented 3D model, thus improving the loading speed and display smoothness of layered and segmented 3D models such as oblique photogrammetry models.

[0036] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0037] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0038] Figure 1 This is a hardware structure block diagram of the terminal of the layered and block-based 3D model node merging method according to an embodiment of this application;

[0039] Figure 2 This is a flowchart of a method for merging nodes in a layered and segmented 3D model according to an embodiment of this application;

[0040] Figure 3 This is a structural block diagram of a layered and segmented three-dimensional model node merging device according to an embodiment of this application. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application. Furthermore, it is understood that although the efforts made in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, modifications to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0042] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0043] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application means two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The terms “first,” “second,” “third,” etc., used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0044] The method embodiments provided in this example can be executed on a terminal, computer, or similar computing device. Taking running on a terminal as an example, Figure 1 This is a hardware structure block diagram of the terminal for the hierarchical and block-based 3D model node merging method according to an embodiment of the present invention. For example... Figure 1 As shown, a terminal may include one or more ( Figure 1 Only one is shown in the diagram. A processor 102 (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data are also shown. Optionally, the terminal may further include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the terminal described above. For example, the terminal may also include components that are more... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0045] The memory 104 can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the layered and segmented 3D model node merging method in this embodiment of the invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, thereby implementing the above-described method. The memory 104 may include high-speed random access memory and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor 102, and these remote memories can be connected to the terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0046] The transmission device 106 is used to receive or send data via a network. Specific examples of the network described above may include a wireless network provided by the terminal's communication provider. In one example, the transmission device 106 includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device 106 may be a Radio Frequency (RF) module used for wireless communication with the Internet.

[0047] This embodiment provides a method for merging nodes in a hierarchical and block-based 3D model. Figure 2 This is a flowchart of a layered and block-based 3D model node merging method according to an embodiment of this application, such as... Figure 2 As shown, the process includes the following steps:

[0048] Step S201: Obtain the root node to be merged, determine the bounding box to be merged of the root node to be merged, determine the overall bounding box to be merged based on the bounding box to be merged, and determine the major axis direction, width axis direction and height axis direction of the overall bounding box to be merged.

[0049] Obtain all root node files, traverse and load each root node file to find the 3D mesh model of each root node file, select a preset number of root nodes to be merged, and obtain the overall bounding box of the preset number of root nodes based on the bounding box of each root node to be merged. The overall bounding box has three axes: length, width, and height.

[0050] Step S202: Divide the bounding box to be merged into a segmented grid along the long axis and the wide axis to obtain the segmented vertices formed by the segmented grid along the long axis and the wide axis, construct a three-dimensional mesh scene including a preset number of root nodes, and extend vertex rays emanating from the segmented vertices along the high axis.

[0051] The bounding box to be merged is divided into CN*KN subdivisions along the length and width axes. CN and KN are set as needed to obtain the length and width axis positions of the subdivision vertices of each subdivision. A 3D mesh scene containing a preset number of root nodes is constructed. The preset number is consistent with the number of root nodes to be merged each time. Vertex rays are emitted along the height axis at the length and width positions of each subdivision vertex.

[0052] Step S203: Determine the target multi-level of detail based on the segmented vertices, the 3D mesh scene, and the vertex rays; and merge the root nodes to be merged into the target level root nodes based on the target multi-level of detail.

[0053] Levels of Detail (LOD) technology refers to allocating rendering resources based on the position and importance of nodes in an object model within the display environment. This reduces the face count and detail of less important objects, resulting in more efficient rendering computations. The original root node refers to the root node of the initially merged layered and segmented 3D model. By traversing and loading each original root node file, the LOD range and LOD calculation method for each root node file can be found. Based on the number of original root node files, the number of root nodes to be merged each time, and the final required number of target root nodes, the final number of newly generated levels can be calculated. Based on the obtained LOD ranges of all original root nodes, a suitable initial value for the LOD range of the new levels can be obtained. Using this initial value and the number L of new levels, the LOD range of each newly generated level can then be obtained.

[0054] Through the above steps, this embodiment of the application obtains the root node to be merged, determines the bounding box of the root node to be merged, and determines the overall bounding box to be merged and its major axis, width axis and height axis based on the bounding box to be merged. The overall bounding box to be merged is divided in the major axis and width axis to obtain the segmented grid. The segmented vertices formed by the segmented grid in the major axis and width axis are obtained. A three-dimensional mesh scene including a preset number of root nodes is constructed. Vertex rays emanating from the segmented vertices extend along the height axis. The target multi-level of detail is determined based on the segmented vertices, the three-dimensional mesh scene and the vertex rays. Based on the target multi-level of detail, the root nodes to be merged are merged into the target level root nodes. This solves the problem of how to maintain the rendering effect while reducing the number of nodes required to initially display the entire layered and blocky three-dimensional model, and improves the loading speed and display smoothness of layered and blocky three-dimensional models such as oblique photogrammetry models.

[0055] In some embodiments, step S203 includes:

[0056] Step S213: Determine the lightweight mesh model and the diffuse texture of the lightweight mesh model based on the segmented vertices, the 3D mesh scene, and the vertex rays.

[0057] Based on the segmented vertices, the 3D mesh scene, and the vertex rays, a lightweight mesh model is determined, imported into the 3D mesh scene, and a diffuse texture of the lightweight mesh model is baked.

[0058] Step S223: Determine the lightweight mesh model and the diffuse map as the target multi-level of detail, and merge the root nodes to be merged into the target level root nodes according to the target multi-level of detail.

[0059] Lightweight mesh data and diffuse maps are generated as 3D mesh model data and 3D mesh texture data for LOD, and the root nodes to be merged are merged into the target level root nodes based on these data.

[0060] In some embodiments, step S213 includes:

[0061] Step S233: Determine lightweight 3D mesh surface data and lightweight 3D mesh vertex data based on the segmented vertices, the 3D mesh scene, and the vertex rays.

[0062] Step S243: Determine the corresponding UV coordinate data based on the lightweight 3D mesh vertex data, and determine the lightweight mesh model based on the UV coordinate data.

[0063] Step S253: Import the lightweight mesh model into the 3D mesh scene to obtain the diffuse texture of the lightweight mesh model.

[0064] In some embodiments, step S233 includes:

[0065] Step S263: Obtain the three-dimensional intersection point formed by the intersection of the vertex ray and the three-dimensional mesh scene, and the three-dimensional intersection point formed by the intersection of the segmented vertex and the three-dimensional mesh scene; connect two adjacent three-dimensional intersection points, and connect adjacent three-dimensional intersection points and the segmented vertex to obtain three-dimensional mesh surface data and three-dimensional mesh vertex data.

[0066] The points where vertex rays intersect with the 3D mesh scene are defined as 3D intersection points, and the points where each segmented vertex intersects with the 3D mesh scene are also defined as 3D intersection points. Traversing these 3D intersection points and segmented vertices, each 3D intersection point is connected to its adjacent 3D intersection point or adjacent segmented vertex to generate 3D mesh surface data. All connected 3D intersection points and segmented vertices form the 3D mesh vertex data.

[0067] Step S273: Reduce the number of faces in the three-dimensional mesh surface data and the three-dimensional mesh vertex data to determine lightweight three-dimensional mesh surface data and lightweight three-dimensional mesh vertex data.

[0068] The 3D mesh surface data and 3D mesh vertex data are subjected to face reduction and lightweighting processing to generate lightweight 3D mesh surface data and lightweight 3D mesh vertex data. For each lightweight 3D mesh vertex data, corresponding UV coordinate data is generated. Based on the UV coordinate data, a lightweight mesh model is determined, and the lightweight mesh model is imported into the 3D mesh scene to bake a diffuse texture map of the lightweight mesh model. In some embodiments, step S203 includes:

[0069] Step S283: Determine the target multi-level of detail based on the segmented vertices, the 3D mesh scene, and the vertex rays.

[0070] Step S293: Create an initial target oblique photography file, store the 3D mesh model data and 3D mesh texture data corresponding to the multi-detail levels of the target into the initial target oblique photography file to obtain a new level target oblique photography file, and determine the new level target oblique photography file as the target level root node.

[0071] Lightweight mesh data and diffuse map are used as the target multi-level of detail. A new oblique photogrammetry file is created as the initial target oblique photogrammetry file. The generated lightweight mesh data and generated diffuse map are written into the initial target oblique photogrammetry file as the target multi-level of detail 3D mesh model data and 3D mesh texture data. At this point, the oblique photogrammetry file after the data has been written is a new level node, namely the target level root node.

[0072] In some embodiments, step S201 includes:

[0073] Step S211: Obtain the root node to be merged, determine the bounding box to be merged of the root node to be merged, determine the overall bounding box to be merged based on the bounding box to be merged, and determine the major axis direction, width axis direction and height axis direction of the overall bounding box to be merged, wherein the thickness of the overall bounding box to be merged is the smallest in the height axis direction.

[0074] In some embodiments, step S201 includes:

[0075] Step S221: Obtain the root node to be merged, determine the bounding box to be merged of the root node to be merged, and add all the bounding boxes to be merged to obtain the overall bounding box to be merged.

[0076] Step S231: Determine the major axis direction, width axis direction, and height axis direction of the overall bounding box to be merged.

[0077] Obtain all root node files, traverse and load each root node file to find the 3D mesh model of each root node file, select a preset number of root nodes to be merged, determine the bounding boxes of the root nodes to be merged, add all the bounding boxes to be merged to obtain the overall bounding box to be merged. The overall bounding box to be merged includes three axes. Based on this overall bounding box to be merged, find the axis with the shortest length, that is, the axis with the smallest thickness of the overall bounding box to be merged. Take the axis with the shortest length as the height axis direction of the overall bounding box to be merged, and the other two axes are the major axis direction and the width axis direction.

[0078] The method described in this application can be repeated until the number of root nodes in the newly generated levels is less than or equal to the final target number of root nodes. Therefore, this application can support the infinite merging of root nodes upwards in a layered, block-based 3D model, such as an oblique photogrammetry model, until only one root node remains. Infinite merging of root nodes upwards means that, for example, if the original layered, block-based 3D model has 3000 root nodes, and we set the process to merge 10 root nodes into one new level node each time, this application will first merge to create a new level with 300 root nodes, then another new level with 30 root nodes, then another new level with 3 root nodes, and finally another new level with 1 root node. The final merged level with one root node becomes the new root node of the entire layered, block-based 3D model. Furthermore, in this application, all the newly merged layers have advantages such as clear details, good rendering effects, and distinct layers. The merging method of the root nodes is very free and flexible, and the number of root nodes to be merged in each merge operation, the total number of layers to be merged, and the final number of root nodes required can be flexibly configured.

[0079] It should be noted that the steps shown in the above process or in the flowchart of the accompanying figures can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0080] This embodiment also provides a layered and segmented 3D model node merging device, which is used to implement the above embodiments and preferred embodiments, and will not be repeated as already described. As used below, the terms "module," "unit," "subunit," etc., can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0081] Figure 3 This is a structural block diagram of a layered and segmented three-dimensional model node merging device according to an embodiment of this application, as shown below. Figure 3 As shown, the device includes a high-axis direction determination module 10, a vertex ray extension module 20, and a root node merging module 30.

[0082] The high axis direction determination module 10 is used to obtain the root node to be merged, determine the bounding box to be merged of the root node to be merged, determine the overall bounding box to be merged based on the bounding box to be merged, and determine the major axis direction, width axis direction and high axis direction of the overall bounding box to be merged.

[0083] The vertex ray extension module 20 is used to divide the bounding box to be merged into a segmented grid in the long axis direction and the wide axis direction to obtain the segmented vertices formed by the segmented grid in the long axis direction and the wide axis direction, construct a three-dimensional mesh scene including a preset number of root nodes, and extend vertex rays emanating from the segmented vertices along the high axis direction.

[0084] The root node merging module 30 is used to determine the target multi-level of detail based on the segmented vertices, the 3D mesh scene, and the vertex rays, and to merge the root nodes to be merged into the target level root nodes based on the target multi-level of detail.

[0085] It should be noted that the above modules can be functional modules or program modules, and can be implemented through software or hardware. For modules implemented through hardware, the above modules can reside in the same processor; or the above modules can be located in different processors in any combination.

[0086] This embodiment also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to perform the steps in any of the above method embodiments.

[0087] Optionally, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor and the input / output device is connected to the processor.

[0088] Optionally, in this embodiment, the processor can be configured to perform the following steps via a computer program:

[0089] Obtain the root node to be merged, determine the bounding box of the root node to be merged, determine the overall bounding box to be merged based on the bounding box to be merged, and determine the major axis direction, width axis direction and height axis direction of the overall bounding box to be merged.

[0090] The bounding box to be merged is divided into segments along the major axis and the width axis to obtain segments. The segments formed by the segments along the major axis and the width axis are obtained. A three-dimensional mesh scene including a preset number of root nodes is constructed. Vertex rays emanating from the segments extend along the height axis.

[0091] Based on the segmented vertices, the 3D mesh scene, and the vertex rays, the target multi-level of detail is determined, and based on the target multi-level of detail, the root nodes to be merged are merged into the target level root nodes.

[0092] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and will not be repeated here.

[0093] Furthermore, in conjunction with the layered and block-based 3D model node merging method in the above embodiments, this application embodiment can provide a storage medium for implementation. This storage medium stores a computer program; when executed by a processor, the computer program implements any of the layered and block-based 3D model node merging methods in the above embodiments.

[0094] Those skilled in the art should understand that the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0096] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for merging nodes in a layered and segmented 3D model. Its features are, Includes the following steps: Obtain the root node to be merged, determine the bounding box of the root node to be merged, determine the overall bounding box to be merged based on the bounding box to be merged, and determine the major axis direction, width axis direction and height axis direction of the overall bounding box to be merged. The bounding box to be merged is divided into segments along the major axis and the width axis to obtain segments. The segments formed by the segments along the major axis and the width axis are obtained. A three-dimensional mesh scene including a preset number of root nodes is constructed. Vertex rays emanating from the segments extend along the height axis. Based on the segmented vertices, the 3D mesh scene, and the vertex rays, the target multi-level of detail is determined, and based on the target multi-level of detail, the root nodes to be merged are merged into the target level root nodes; The step of determining the target multi-level of detail (MLD) based on the segmented vertices, the 3D mesh scene, and the vertex rays, and merging the root nodes to be merged into the target level root nodes based on the target MLD, includes: Based on the segmented vertices, the 3D mesh scene, and the vertex rays, determine the target's multi-level of detail; An initial target oblique photography file is created, and the 3D mesh model data and 3D mesh texture data corresponding to the multi-detail levels of the target are stored in the initial target oblique photography file to obtain a new level target oblique photography file. The new level target oblique photography file is determined as the root node of the target level.

2. The method for merging nodes in a layered and segmented 3D model according to claim 1, characterized in that, The step of determining the target multi-level of detail (MLD) based on the segmented vertices, the 3D mesh scene, and the vertex rays, and merging the root nodes to be merged into the target level root nodes based on the target MLD, includes: Based on the segmented vertices, the 3D mesh scene, and the vertex rays, determine the lightweight mesh model and the diffuse texture of the lightweight mesh model; The lightweight mesh model and the diffuse map are determined as the target multi-level of detail. Based on the target multi-level of detail, the root nodes to be merged are merged into the target level root nodes.

3. The method for merging nodes in a layered and segmented 3D model according to claim 2, characterized in that, The step of determining the lightweight mesh model and the diffuse map of the lightweight mesh model based on the segmented vertices, the 3D mesh scene, and the vertex rays includes: Based on the segmented vertices, the 3D mesh scene, and the vertex rays, determine the lightweight 3D mesh surface data and the lightweight 3D mesh vertex data; Based on the lightweight 3D mesh vertex data, the corresponding UV coordinate data is determined, and based on the UV coordinate data, the lightweight mesh model is determined. The lightweight mesh model is imported into the 3D mesh scene to obtain the diffuse texture of the lightweight mesh model.

4. The method for merging nodes in a layered and segmented 3D model according to claim 3, characterized in that, The step of determining lightweight 3D mesh surface data and lightweight 3D mesh vertex data based on the segmented vertices, the 3D mesh scene, and the vertex rays includes: Obtain the three-dimensional intersection point formed by the intersection of the vertex ray and the three-dimensional mesh scene, and the three-dimensional intersection point formed by the intersection of the segmented vertex and the three-dimensional mesh scene. Connect two adjacent three-dimensional intersection points, and connect adjacent three-dimensional intersection points and the segmented vertex to obtain three-dimensional mesh surface data and three-dimensional mesh vertex data. The three-dimensional mesh surface data and the three-dimensional mesh vertex data are reduced in size to determine lightweight three-dimensional mesh surface data and lightweight three-dimensional mesh vertex data.

5. The method for merging nodes in a layered and segmented three-dimensional model according to any one of claims 1 to 4, characterized in that, The steps of obtaining the root node to be merged, determining the bounding box of the root node to be merged, determining the overall bounding box to be merged based on the bounding box, and determining the major axis, width axis, and height axis of the overall bounding box to be merged include: Obtain the root node to be merged, determine the bounding box of the root node to be merged, determine the overall bounding box to be merged based on the bounding box to be merged, and determine the major axis direction, width axis direction and height axis direction of the overall bounding box to be merged, wherein the thickness of the overall bounding box to be merged is the smallest in the height axis direction.

6. The method for merging nodes in a layered and segmented 3D model according to claim 5, characterized in that, The steps of obtaining the root node to be merged, determining the bounding box of the root node to be merged, determining the overall bounding box to be merged based on the bounding box, and determining the major axis, width axis, and height axis of the overall bounding box to be merged include: Obtain the root node to be merged, determine the bounding box of the root node to be merged, and add all the bounding boxes to be merged to obtain the overall bounding box to be merged. Determine the major axis, width axis, and height axis of the overall bounding box to be merged.

7. A device for merging nodes in a layered and segmented three-dimensional model, characterized in that, Includes a high-axis direction determination module, a vertex ray extension module, and a root node merging module: The high axis direction determination module is used to obtain the root node to be merged, determine the bounding box to be merged of the root node to be merged, determine the overall bounding box to be merged based on the bounding box to be merged, and determine the major axis direction, width axis direction and high axis direction of the overall bounding box to be merged. The vertex ray extension module is used to divide the bounding box to be merged into a segmented grid in the long axis direction and the wide axis direction to obtain the segmented vertices formed by the segmented grid in the long axis direction and the wide axis direction, construct a three-dimensional mesh scene including a preset number of root nodes, and extend vertex rays emanating from the segmented vertices along the high axis direction. The root node merging module is used to determine the target multi-level of detail based on the segmented vertices, the 3D mesh scene, and the vertex rays, and to merge the root nodes to be merged into the target level root nodes based on the target multi-level of detail. The step of determining the target multi-level of detail (MLD) based on the segmented vertices, the 3D mesh scene, and the vertex rays, and merging the root nodes to be merged into the target level root nodes based on the target MLD, includes: Based on the segmented vertices, the 3D mesh scene, and the vertex rays, determine the target's multi-level of detail; An initial target oblique photography file is created, and the 3D mesh model data and 3D mesh texture data corresponding to the multi-detail levels of the target are stored in the initial target oblique photography file to obtain a new level target oblique photography file. The new level target oblique photography file is determined as the root node of the target level.

8. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and the processor is configured to run the computer program to perform the hierarchical block 3D model node merging method according to any one of claims 1 to 6.

9. A storage medium, characterized in that, The storage medium stores a computer program, wherein the computer program is configured to execute the hierarchical block 3D model node merging method according to any one of claims 1 to 6 when running.

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