Method and apparatus for three-dimensional subsurface space visualization, computer, storage medium

Abstract

The application relates to the technical field of three-dimensional visualization, and discloses a method for three-dimensional underground space visualization, which comprises the following steps: in a three-dimensional scene, acquiring terrain boundary sampling points and building structure boundary sampling points of an underground space; acquiring an outer boundary line at a section of the underground space according to the terrain boundary sampling points, and acquiring a building structure boundary line according to the building structure boundary sampling points of the underground space; acquiring the section of the underground space according to the outer boundary line at the section and the building structure boundary line; and loading and displaying the section of the underground space through a preset three-dimensional engine. The method improves the effect of three-dimensional visualization and display of the underground space. The application also discloses a device for three-dimensional underground space visualization, a computer and a storage medium.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of three-dimensional visualization, for example to a method and device for three-dimensional underground space visualization, a computer and a storage medium. BACKGROUND

[0002] With the continuous progress and development of modern city construction, the utilization and development of urban underground space are paid more and more attention, but since the subjects involved in the urban underground space are often hidden, it is more difficult to display the underground space structure than the ground structure. At present, the ground is hidden or semi-transparent to display and analyze the urban underground space.

[0003] In the process of implementing the embodiments of the present disclosure, it is found that at least the following problems exist in the related art:

[0004] In the prior art, the underground space is displayed by hiding or semi-transparency of the ground, which results in unclear scene elements and obvious split of ground and underground elements, thereby leading to poor display effect of the underground space. SUMMARY

[0005] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an overall description of the application, nor is it intended to identify key / important elements or delineate the scope of the embodiments. It is only a prelude to the detailed description that follows.

[0006] The embodiments of the present disclosure provide a method and device for three-dimensional underground space visualization, a computer and a storage medium, so as to improve the display effect of the underground space.

[0007] In some embodiments, the method for three-dimensional underground space visualization comprises: in a three-dimensional scene, acquiring a terrain boundary sampling point and a building structure boundary sampling point of the underground space;

[0008] According to the terrain boundary sampling point, an outer boundary line at a section of the underground space is acquired, and according to the building structure boundary sampling point, a building structure boundary line is acquired;

[0009] According to the outer boundary line at the section and the building structure boundary line, the section of the underground space is acquired;

[0010] The section of the underground space is loaded and displayed by a preset three-dimensional engine.

[0011] In some embodiments, the device for three-dimensional underground space visualization comprises: a sampling point acquisition module configured to acquire a terrain boundary sampling point and a building structure boundary sampling point of the underground space in a three-dimensional scene;

[0012] a boundary line obtaining module configured to obtain an outer boundary line at a section of the underground space according to the terrain boundary sampling points, and obtain a building boundary line according to the building boundary sampling points of the underground space;

[0013] a section obtaining module configured to obtain the section of the underground space according to the outer boundary line at the section and the building boundary line;

[0014] a display module configured to load and display the section of the underground space by a preset three-dimensional engine.

[0015] In some embodiments, the device for three-dimensional underground space visualization comprises a processor and a memory storing program instructions, the processor is configured to execute the method for three-dimensional underground space visualization as described above when running the program instructions.

[0016] In some embodiments, the computer comprises the device for three-dimensional underground space visualization as described above.

[0017] In some embodiments, the storage medium stores program instructions, the program instructions execute the method for three-dimensional underground space visualization as described above when running.

[0018] The method and device for three-dimensional underground space visualization, the computer, and the storage medium provided by the embodiments of the present disclosure can achieve the following technical effects: the outer boundary line at the section of the underground space and the building boundary line can be obtained through the terrain boundary sampling points and the building boundary sampling points of the underground space obtained in the three-dimensional scene; then, the section of the underground space can be obtained according to the outer boundary line at the section and the building boundary line; and finally, the section of the underground space can be loaded and displayed by a preset three-dimensional engine. The three-dimensional visualization display of the underground space is realized, and the scene elements displayed by the way of excavation section are clearer. Meanwhile, the outer boundary line at the section is obtained through the terrain boundary sampling points, and the section of the underground space is obtained according to the outer boundary line at the section and the building boundary line. The relationship between the aboveground building and the building of the underground space is considered, the display of the aboveground and underground elements is more coherent, and thus the display effect of the underground space is improved.

[0019] The general description above and the following description below are exemplary and explanatory only and are not intended to be limiting. BRIEF DESCRIPTION OF DRAWINGS

[0020] One or more embodiments are illustrated by way of example in the figures that are not intended to be limiting of the embodiments as disclosed herein. Like numbers refer to like elements throughout the description, some of which elements are not labeled in each figure in the interest of clarity. Not all elements of the embodiments are called out in the description below, as some of these elements are matters of design choice and are treated as equivalents.

[0021] Figure 1 is a schematic diagram of a method for three-dimensional underground space visualization provided by an embodiment of the present disclosure;

[0022] Figure 2(a) is a schematic diagram of a lowest point filling method according to an embodiment of the present disclosure;

[0023] Figure 2(b) is a schematic diagram of a highest point filling method according to an embodiment of the present disclosure;

[0024] Figure 2(c) is a schematic diagram of a linear interpolation method according to an embodiment of the present disclosure;

[0025] Figure 3 is a schematic diagram of a device for three-dimensional underground space visualization provided by an embodiment of the present disclosure;

[0026] Figure 4 is a schematic diagram of a device for three-dimensional underground space visualization provided by another embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] In order to enable a more detailed understanding of the features and technical content of the embodiments of the present disclosure, the implementation of the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings, which are for reference only and do not limit the embodiments of the present disclosure. In the following technical description, in order to facilitate explanation, a plurality of details are provided to provide a full understanding of the disclosed embodiments. However, one or more embodiments can still be implemented without these details. In other cases, well-known structures and devices can be simplified to facilitate the drawings.

[0028] The terms "first", "second", and the like in the specification and claims of the embodiments of the present disclosure and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present disclosure described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0029] Unless otherwise specified, the term "a plurality of" means two or more.

[0030] In the embodiments of the present disclosure, the character " / " represents an "or" relationship between the objects before and after it. For example, A / B means: A or B.

[0031] The term "and / or" is a description of the relationship between the objects, which means that there can be three relationships. For example, A and / or B means: A or B, or, A and B, the three relationships.

[0032] The term "corresponding" can refer to an association or binding relationship. A and B correspond to each other means that there is an association or binding relationship between A and B.

[0033] The embodiment of the present disclosure is applied to a display scene of underground space. Firstly, underground building elements such as terrain boundaries, underground garages, underground rail transit stations, tunnels and air defense caverns are extracted in a city three-dimensional scene; then, based on a ray detection module interface of a three-dimensional visualization engine, terrain boundary sampling points and underground space building boundary sampling points are identified according to a preset scanning line density interval parameter and a dynamic real-time underground space profile position. Next, clustering analysis is performed on the underground space building boundary sampling points, and building boundary discrete points of different buildings are classified and identified. And the terrain boundary sampling points and the classified building boundary discrete points are used to generate an outer boundary line and a building boundary line at the underground space section; finally, according to the outer boundary line and the building boundary line at the section, a triangular subdivision algorithm is used to construct a geometric grid and set a texture coordinate, and a complete underground space section is formed. The section of the underground space is loaded and displayed by a preset three-dimensional engine. The scheme can quickly and accurately extract the underground space section at any position in the city three-dimensional scene in real time, and the multi-section enclosure forms a closed underground space, effectively solving the problem that the traditional hidden or semi-transparent method is difficult to express the complex underground space relationship, and the real-time dynamic excavation effect can better exhibit the visualization effect of the city underground space structure.

[0034] In combination Figure 1 As shown in the drawings, the embodiment of the present disclosure provides a method for three-dimensional underground space visualization, comprising:

[0035] Step S101, in a three-dimensional scene, terrain boundary sampling points and underground space building boundary sampling points are obtained.

[0036] Step S102, an outer boundary line at the section of the underground space is obtained according to the terrain boundary sampling points, and a building boundary line is obtained according to the underground space building boundary sampling points.

[0037] Step S103, the section of the underground space is obtained according to the outer boundary line at the section and the building boundary line.

[0038] Step S104, the section of the underground space is loaded and displayed by a preset three-dimensional engine.

[0039] The method for three-dimensional underground space visualization provided in the embodiments of the present disclosure can obtain the outer boundary line and the building boundary line of the underground space at the section by obtaining the terrain boundary sampling points and the building boundary sampling points of the underground space in the three-dimensional scene, and then obtain the section of the underground space according to the outer boundary line and the building boundary line, and then load and display the section of the underground space by the preset three-dimensional engine. The three-dimensional visualization of the underground space is realized, and the scene elements of the display can be made more clear by the way of excavation section. Meanwhile, the outer boundary line at the section is obtained by the terrain boundary sampling points, and the section of the underground space is obtained according to the outer boundary line and the building boundary line. The relationship between the aboveground building and the building of the underground space is considered, the display of the aboveground and underground elements is made more coherent, and thus the display effect of the underground space is improved.

[0040] Optionally, the terrain boundary sampling points and the building boundary sampling points of the underground space are obtained in the three-dimensional scene, including: identifying the three-dimensional terrain elements and the building elements of the underground space in the three-dimensional scene; performing ray detection on the three-dimensional terrain elements to obtain the terrain boundary sampling points; and performing ray detection on the building elements of the underground space to obtain the building boundary sampling points of the underground space.

[0041] Optionally, the three-dimensional terrain elements and the building elements of the underground space are identified, including: identifying the three-dimensional terrain elements and the building elements of the underground space in the three-dimensional scene by using the three-dimensional engine.

[0042] The 3DMax (3D Studio Max, three-dimensional modeling software) model results are imported into the editor of the UE4 (Unreal Engine 4) three-dimensional engine, the three-dimensional terrain elements and the building elements of the underground space in the three-dimensional scene are classified by using the UE4 three-dimensional engine, and are marked respectively. For example, terrain represents the three-dimensional terrain elements, and underground represents the building elements of the underground space. The building of the underground space includes underground pipe corridors, underground garages, underground rail transit stations, tunnels and underground shelters, etc.

[0043] Two world coordinate point positions are selected arbitrarily in the UE4 scene as the start position and the end position of the underground space section to be obtained, so that the end position and the section depth of the underground space section can be set in the three-dimensional world coordinate system in real time.

[0044] The C++ interface of the KismetSystem module of the UE4 is used to encapsulate the LineTraceMultiForObjects (ray detection interface) to perform ray detection on the three-dimensional terrain elements to obtain the terrain boundary sampling points. The KismetSystem is a kind of visual scripting system.

[0045] Specifically, all terrain sampling points and position coordinates of the ray intersecting with the three-dimensional scene are obtained according to the preset ray position and direction. A set of terrain boundary sampling points is obtained according to a preset scanning line density interval parameter. And the elevation information of the terrain boundary sampling points is obtained.

[0046] The elevation of the terrain boundary sampling point is obtained by calculating Pi.RealHeight=Min{LineTrace(Pi.X,Pi.Y,terrain).Z}. Wherein, Pi.RealHeight is the elevation information of the i th terrain boundary sampling point; Pi.X is the horizontal coordinate value of the i th terrain boundary sampling point, and Pi.Y is the vertical coordinate value of the i th terrain boundary sampling point. I=0,1,2,3……n, n is an integer. LineTrace() represents obtaining the coordinate information of all terrain boundary sampling points intersected by the ray and the three-dimensional scene. Terrain represents a three-dimensional terrain element. Min{} represents obtaining the sampling point information with the minimum elevation from multiple sampling points, and Z represents the elevation value of the terrain boundary sampling point.

[0047] The three-dimensional coordinate information of the terrain boundary sampling point is obtained by calculating The three-dimensional coordinate information of the terrain boundary sampling point is obtained by calculating

[0048] Optionally, after obtaining the terrain boundary sampling points, it further includes: in the case that the elevation of the terrain boundary sampling point is invalid, determining that the terrain corresponding to the terrain boundary sampling point is a hollow.

[0049] In the case that the elevation of the terrain boundary sampling point is invalid, the elevation value is empty. In the case that the terrain is a hollow, the terrain boundary sampling points corresponding to the terrain hollow are supplemented in a difference mode. In this way, the continuity of the terrain boundary can be ensured, thereby improving the display effect of the terrain space.

[0050] Specifically, the interpolation method includes one or more of the following: minimum point filling method, maximum point filling method, and linear interpolation method. For example, Figure 2(a) shows a schematic diagram of the minimum point filling method. Figure 2(b) shows a schematic diagram of the maximum point filling method. Figure 2(c) shows a schematic diagram of the linear interpolation method.

[0051] Optionally, ray detection is performed on the building elements of the underground space to obtain the building boundary sampling points of the underground space. This includes: using the blueprint script function of the UE4 3D engine, the ray detection interface, to perform ray detection on the opposite side according to the boundaries of the underground space cross section in the four directions of up, down, left and right, to scan the boundary points of all buildings in the cross section area, and obtain the building boundary sampling points of all underground spaces.

[0052] Alternatively, by calculating A = {A} 上→下 A 右→左 A 下→上 A 左→右 Obtain the set of sampling points for the boundaries of structures in the underground space. Where A is the set of sampling points for the boundaries of structures in the underground space. 上→下 A is the set of sampling points obtained by ray detection from the upper boundary of the underground space section to be acquired; 右→左 A is the set of sampling points obtained by ray detection from the right boundary of the underground space section to be acquired; 下→上 A is the set of sampling points obtained by ray detection from the lower boundary of the underground space section to be acquired; 左→右 This is the set of sampling points obtained by ray detection from the left boundary of the underground space section to be acquired.

[0053] Optionally, by calculating A 上→下 ={LineTrace(P j上 P j下 ,underground)}, obtain A 上→下 , where A 上→下 P represents the set of sampling points obtained from ray detection of the upper boundary of the underground space section to be acquired. j上 This indicates the ray origin at the upper boundary, which is a pre-set extreme value. P j下 This indicates the endpoint of the ray at the upper boundary, which is a pre-set minimum value. "Underground" represents underground structural elements.

[0054] Optionally, by calculating A 右→左 ={LineTrace(P j右 P j左 ,underground)}, obtain A右→左 wherein A 右→左 is a set of sampling points obtained from the right boundary of the underground space section to be acquired by ray detection. j右 represents the ray start point on the right boundary, which is a pre-set extreme right value. j左 represents the ray end point on the right boundary, which is a pre-set extreme left value.

[0055] Optionally, A 下→上 is obtained by calculating A j′下 = {LineTrace(P j′上 , P 下→上 , underground)}, wherein A 下→上 is a set of sampling points obtained from the lower boundary of the underground space section to be acquired by ray detection. j′下 represents the ray start point on the lower boundary, which is a pre-set extreme low value. j′上 represents the ray end point on the lower boundary, which is a pre-set extreme high value.

[0056] Optionally, A 左→右 is obtained by calculating A j′左 = {LineTrace(P j′右 , P 左→右 , underground)}, wherein A 左→右 is a set of sampling points obtained from the left boundary of the underground space section to be acquired by ray detection. j′左 represents the ray start point on the left boundary, which is a pre-set extreme left value. j′右 represents the ray end point on the left boundary, which is a pre-set extreme right value.

[0057] Preferably, the scan line density interval parameter is set to 0.1 m. In this way, the sampling accuracy is guaranteed, and the scanning program time efficiency is also guaranteed.

[0058] Optionally, the building boundary line of the underground space is acquired according to the building boundary sampling points of the underground space, including: classifying the building boundary sampling points of the underground space according to building types to acquire a set of building island discrete points of at least one building. The convex hull algorithm is used to respectively perform boundary line extraction processing on each set of building island discrete points to obtain the building boundary line of each building in the underground space.

[0059] Optionally, the building structure boundary sampling points of the underground space are classified according to the building structure types, and a building structure island discrete point set of at least one building structure is obtained, including: using a DBSCAN (Density-Based Spatial Clustering of Applications with Noise) clustering algorithm, classifying the building structure boundary sampling points of the underground space according to the building structure types, and obtaining the building structure island discrete point set of at least one building structure.

[0060] In some embodiments, in order to reduce the calculation amount of the three-dimensional engine, the three-dimensional building structure island discrete point space coordinates are projected and converted into two-dimensional discrete point coordinates, and the three-dimensional terrain boundary sampling point space coordinates are converted into two-dimensional sampling point coordinates. The three-dimensional space coordinates are converted into two-dimensional coordinates by using a mathematical calculation function library of UE4, for example, in a left-handed coordinate system, rotating around a target rotation axis n by a rotation angle θ to obtain a quaternion q (x, y, z, w). Wherein x, y, z are the imaginary parts of the four elements, that is, the three-dimensional coordinate values. w is the real part of the quaternion.

[0061] Optionally, the four elements are obtained by calculating

[0062] obtain four elements. Wherein q (x, y, z, w) is a quaternion, n is a target rotation axis, and θ is a rotation angle. represents the rotation value of the target rotation axis n in the x-axis component direction, represents the rotation value of the target rotation axis n in the y-axis component direction, represents the rotation value of the target rotation axis n in the z-axis component direction.

[0063] The three-dimensional coordinate values are converted into two-dimensional coordinate values by a rotation matrix.

[0064] The rotation matrix is

[0065] In this way, the three-dimensional building structure island discrete point space coordinates and the three-dimensional terrain boundary sampling point space coordinates are converted into two-dimensional discrete point coordinates. The calculation amount of the three-dimensional engine can be reduced.

[0066] Optionally, the building structure boundary sampling points of the underground space are classified according to the building structure types by using a DBSCAN clustering algorithm, including: setting initialization parameter values in advance, for example, setting a field radius and a minimum number of building structure boundary sampling points in the field in advance. Wherein Radius represents the field radius, and MinPts represents the minimum number of building structure boundary sampling points in the field. A field set A of each clustering vertex in a building structure boundary sampling point set A of the underground space is obtained PoIn a recursive manner, the data is clustered in a depth-first manner, and the clustering operation is performed on the points in the field of each clustering vertex to complete the classification analysis of all the building boundary sampling points and form a plurality of building island discrete point sets.

[0067] Optionally, the distance between each clustering vertex and each sampling point is calculated by A set of fields of each clustering vertex is obtained Po A set of fields of the oth clustering vertex, o being a positive integer, P o The oth clustering vertex. P j The jth sampling point in the set of building boundary sampling points A of the underground space. Dist2D(P o ,P j ) represents the two-dimensional space distance between the oth clustering vertex and the jth sampling point in the building boundary of the underground space. If P o The number of building boundary sampling points in the field set corresponding to the clustering vertex is greater than MinPts, and P o The clustering vertex is a core point.

[0068] In some embodiments, the field radius can be set to 10 m, and the minimum number of building boundary sampling points in the field can be set to 20. In this way, the main structure of the underground building can be identified, and the noise sampling points can be filtered.

[0069] Optionally, a convex hull algorithm is used to extract the boundary line of each building island discrete point set to obtain the building boundary line of each building in the underground space, including: for each building island discrete point set, the following operations are performed in turn: setting the first discrete point in each set as a base point; forming vectors with the base point from the other discrete points except the base point, and sorting the vectors in descending order according to the cosine value of the angle between each vector and the horizontal coordinate, sequentially deleting the vectors not on the convex hull, backtracking the vectors with opposite rotation directions, obtaining the vectors connected in the first place in turn, and adding all the vectors connected in the first place in turn to convert them into coordinate values to form the building boundary line of each building. Optionally, the rotation direction is determined by the cross product. Since each building island discrete point is a two-dimensional coordinate, the building boundary line of each building is also a two-dimensional building boundary line. This reduces the calculation amount of the three-dimensional engine, improves the rate of visual display of the underground space section, and improves the effect of visual display of the underground space section.

[0070] Optionally, the outer boundary line at the section of the underground space is obtained according to the terrain boundary sampling points, including: using a convex hull algorithm to extract the boundary line of the terrain boundary sampling points to obtain the outer boundary line at the section of the underground space.

[0071] Optionally, the terrain boundary sampling points are subjected to a boundary line extraction processing by using a convex hull algorithm to obtain the outer boundary line of the underground space at the section, including: setting the first discrete point in the terrain boundary sampling point set as a base point; forming a vector with the base point and other discrete points except the base point, and sorting the vectors from small to large according to the included angle between the vectors and the horizontal coordinates, sequentially deleting the vectors not on the convex hull, backtracking the vectors in the opposite rotation direction, obtaining the vectors sequentially connected at the beginning, and sequentially accumulating all the vectors connected at the beginning to convert into coordinate values to form the outer boundary line of the underground space at the section. Since the terrain boundary sampling points are two-dimensional coordinates, the outer boundary line of the underground space at the section is also the outer boundary line at the section. The calculation amount of the three-dimensional engine is reduced, the rate of visual display of the underground space section is improved, and the effect of visual display of the underground space section is improved.

[0072] Optionally, according to the outer boundary line at the section and the building boundary line, the underground space section is obtained, including: performing a geometric mesh construction processing on the outer boundary line at the section and the building boundary line by using a triangulation algorithm to obtain vertex data and vertex sequence of a geometric mesh corresponding to the underground space section; obtaining texture coordinates corresponding to the vertex data of the geometric mesh; and drawing the underground space section according to the vertex data, the vertex sequence and the corresponding texture coordinates of the geometric mesh.

[0073] In some optional embodiments, the two-dimensional outer boundary line at the section and the two-dimensional building boundary line are added to a triangulation tool by using an OpenGL (Open Graphics Library) library to construct the vertex data and the vertex sequence of the geometric mesh corresponding to the underground space section to be obtained. The UV texture coordinates corresponding to the vertex data of the geometric mesh are calculated by using the underground space section material of UE4.

[0074] The texture coordinates corresponding to the vertex data of each geometric mesh are calculated in the two-dimensional discrete point space.

[0075] Optionally, the texture coordinates (U, V) corresponding to the vertex P of the geometric mesh are obtained by calculating s s .X represents the X coordinate of the vertex of the geometric mesh, P s .Y represents the Y coordinate of the vertex of the geometric mesh. MinX represents the minimum value of the X component of the vertex of the geometric mesh, MaxX represents the maximum value of the X component of the vertex of the geometric mesh. MinY represents the minimum value of the Y component of the vertex of the geometric mesh, and MaxY represents the maximum value of the Y component of the vertex of the geometric mesh. U represents the U component coordinate value of the two-dimensional texture, and V represents the V component coordinate value of the two-dimensional texture. Wherein, MinX = Min{P s ​​Xs = 0, 1, …, Numpnt}, MaxX = Max{P s Xs = 0, 1, …, Numpnt}. Numpnt represents the total number of vertices of the geometric mesh.

[0076] Optionally, the vertex data of the geometric mesh is converted from two-dimensional coordinates to three-dimensional coordinates by using the inverse matrix of the rotation matrix T, to obtain a three-dimensional geometric mesh.

[0077] Optionally, the vertex data of the three-dimensional geometric mesh is obtained by calculating The vertex data of the three-dimensional geometric mesh is obtained. Wherein, T -1 is the inverse matrix of the rotation matrix T. Boundarty2D.X represents the X coordinate value of the vertex of the two-dimensional geometric mesh; Boundarty2D.Y represents the Y coordinate value of the vertex of the two-dimensional geometric mesh; AverageZ represents the stored three-dimensional coordinate Z value in the process of three-dimensional projection to two-dimensional; Boundarty3D represents the vertex coordinate of the three-dimensional geometric mesh.

[0078] Optionally, the cross section of the underground space is drawn according to the vertex data of the geometric mesh, the vertex sequence and the corresponding texture coordinates, comprising: drawing the three-dimensional geometric mesh of the cross section of the underground space to be obtained by using the three-dimensional vertex data and the vertex sequence by the three-dimensional engine, and setting the corresponding material texture for the geometric mesh according to the corresponding texture coordinates of each vertex, so as to obtain the cross section of the underground space.

[0079] In some embodiments, in the urban three-dimensional scene, the position where the underground space excavation analysis needs to be performed is selected at will, a plurality of underground space cross sections are created, for example, 5 cross sections (4 vertical cross sections of the excavation pit and 1 horizontal cross section of the bottom of the pit), and a closed underground space is enclosed. The building sampling points of the underground space excavation position can be obtained in real time, and the cross section of the excavation position is obtained, so as to realize the effect of real-time dynamic visualization of the underground space.

[0080] In some embodiments, in the UE4 three-dimensional engine, the three-dimensional scene real-time dynamic excavation analysis is performed based on UMG (UMG-Unreal Motion Graphics interface control), the UI (UI-User Interface) tool adjusts the display and hiding of the cutting box by setting the center point of the excavation pit, the direction of the pit in the world coordinate, and the length, width and height parameters of the pit, which improves the visualization effect. Through dynamic adjustment of the parameters of the visualization tool, the cross section parameters are modified in real time, the underground space of the urban three-dimensional scene can be quickly and intuitively visualized, the clarity of the scene elements during the underground space display is improved, and the effect of the underground space visualization display is improved.

[0081] The embodiment of the present disclosure realizes the visual display of the underground space by integrating the classification of the underground space element entity, the ray detection, the discrete point aggregation, the island identification, the discrete point boundary line extraction, and the triangular mesh construction, can intuitively display the relationship between the underground space building and the aboveground building and the topological relationship of the underground space itself. The embodiment of the present disclosure solves the problems of the traditional expression method, such as the unclear scene elements, the too obvious split of the aboveground and underground elements, and the like, and improves the effect of the visual display of the underground space.

[0082] In combination with Figure 3 As shown in the drawings, the embodiment of the present disclosure provides a device for three-dimensional underground space visualization, which comprises a sampling point acquisition module 301, a boundary line acquisition module 302, a cross section acquisition module 303, and a display module 304. The sampling point acquisition module 301 is configured to acquire the terrain boundary sampling points and the building boundary sampling points of the underground space in a three-dimensional scene. The boundary line acquisition module 302 is configured to acquire the outer boundary line at the cross section of the underground space according to the terrain boundary sampling points, and acquire the building boundary line according to the building boundary sampling points of the underground space. The cross section acquisition module 303 is configured to acquire the cross section of the underground space according to the outer boundary line at the cross section and the building boundary line. The display module 304 is configured to load and display the cross section of the underground space through a preset three-dimensional engine.

[0083] The device for three-dimensional underground space visualization provided by the embodiment of the present disclosure can acquire the outer boundary line at the cross section of the underground space and the building boundary line through the terrain boundary sampling points and the building boundary sampling points of the underground space acquired in the three-dimensional scene, and then acquire the cross section of the underground space according to the outer boundary line at the cross section and the building boundary line, and then load and display the cross section of the underground space through a preset three-dimensional engine. The device realizes the three-dimensional visual display of the underground space, and can make the scene elements displayed more clearly through the excavation of the cross section. At the same time, the outer boundary line at the cross section is acquired through the terrain boundary sampling points, and the cross section of the underground space is acquired according to the outer boundary line at the cross section and the building boundary line. The relationship between the aboveground building and the underground building is considered, the display of the aboveground and underground elements is more coherent, and thus the display effect of the underground space is improved.

[0084] In combination with Figure 4As shown, the apparatus for three-dimensional underground space visualization provided by the embodiments of the present disclosure includes a processor 400 and a memory 401 storing program instructions. Optionally, the apparatus can further include a communication interface 402 and a bus 403. The processor 400, the communication interface 402 and the memory 401 can communicate with each other through the bus 403. The communication interface 402 can be used for information transmission. The processor 400 can invoke the program instructions in the memory 401 to execute the method for three-dimensional underground space visualization of the above-mentioned embodiments.

[0085] In addition, the program instructions in the memory 401 can be implemented in the form of software functional units and sold or used as independent products, which can be stored in a computer readable storage medium.

[0086] The memory 401 as a computer readable storage medium can be used to store software programs, computer executable programs, such as program instructions / modules corresponding to the method in the embodiments of the present disclosure. The processor 100 executes the program instructions / modules stored in the memory 401, thereby performing functional applications and data processing, i.e. implementing the method for three-dimensional underground space visualization in the above-mentioned embodiments.

[0087] The memory 401 can include a program storage area and a data storage area. The program storage area can store an operating system and at least one application required by a function; the data storage area can store data created according to the use of the terminal device, etc. In addition, the memory 401 can include a high-speed random access memory, and can also include a non-volatile memory.

[0088] The embodiments of the present disclosure provide a computer including the apparatus for three-dimensional underground space visualization as described above.

[0089] The embodiments of the present disclosure provide a storage medium storing program instructions, which, when executed, perform the method for three-dimensional underground space visualization as described above.

[0090] The embodiments of the present disclosure provide a computer program product including a computer program stored on a computer readable storage medium, the computer program including program instructions, which, when executed by a computer, cause the computer to perform the method for three-dimensional underground space visualization as described above.

[0091] The above-mentioned computer readable storage medium can be a transitory computer readable storage medium or a non-transitory computer readable storage medium.

[0092] The technical solutions of the embodiments of the present disclosure can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes one or more instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method disclosed in the embodiments of the present disclosure. The aforementioned storage medium can be a non-transitory storage medium, including: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes, and can also be a transitory storage medium.

[0093] The above description and drawings sufficiently illustrate the embodiments of the present disclosure to enable one skilled in the art to practice them. Other embodiments can include structural, logical, electrical, process, and other changes. The embodiments represent only a few of the possible variations. Individual components and functions are optional unless explicitly required, and the order of operations can be changed. Parts and features of some embodiments can be included in or replace parts and features of other embodiments. Also, the words used in this application are used only to describe the embodiments and not to limit the claims. As used in the description of the embodiments and the claims, unless the context clearly requires otherwise, the singular forms "a," "an," and "the" are intended to include the plural forms as well. Similarly, the term "and / or" as used in this application refers to any and all possible combinations of one or more associated listed items. In addition, when used in this application, the term "comprise" and its variations "comprises" and / or comprises" and the like mean the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Without more limitations, the element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, or device including the stated element. In this document, each embodiment focuses on the differences from other embodiments, and the same or similar parts between embodiments can be referred to each other. For the method, product, etc. disclosed in the embodiments, if it corresponds to the method part disclosed in the embodiments, the relevant part can be referred to the description of the method part.

[0094] Those skilled in the art can understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods for each specific application to realize the described functions, but such implementation should not be considered beyond the scope of the embodiments of the present disclosure. The skilled person can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0095] In the embodiments disclosed herein, the disclosed methods, products (including but not limited to devices, equipment, etc.) can be implemented in other ways. For example, the above-described device embodiments are only schematic, for example, the division of the units can only be a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms. The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to implement the embodiments. In addition, each functional unit in the embodiments of the present disclosure can be integrated in one processing unit, or each unit can be a physically independent unit, or two or more units can be integrated in one unit.

[0096] The computer program instructions can also be loaded onto a computer, other programmable data processing apparatus, or other processing device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other processing device to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

Claims

1. A method for three-dimensional subsurface space visualization, characterized by, The method comprises the following steps: acquiring terrain boundary sampling points and building boundary sampling points of the underground space in a three-dimensional scene; acquiring an outer boundary line at a section of the underground space according to the terrain boundary sampling points, and acquiring a building boundary line according to the building boundary sampling points of the underground space; acquiring the section of the underground space according to the outer boundary line at the section and the building boundary line; loading and displaying the section of the underground space by a preset three-dimensional engine; wherein, after acquiring the terrain boundary sampling points, further comprising: determining that the terrain corresponding to the terrain boundary sampling points is a hollow in the case that the elevation of the terrain boundary sampling points is invalid; and supplementing the terrain boundary sampling points corresponding to the terrain hollow in a difference mode in the case that the terrain is a hollow; acquiring the outer boundary line at the section of the underground space according to the terrain boundary sampling points comprises: performing boundary line extraction processing on the terrain boundary sampling points by using a convex hull algorithm to obtain the outer boundary line at the section of the underground space; acquiring the section of the underground space according to the outer boundary line at the section and the building boundary line comprises: performing geometric mesh construction processing on the outer boundary line at the section and the building boundary line by using a triangulation algorithm to obtain vertex data and vertex sequence of a geometric mesh corresponding to the section of the underground space; acquiring texture coordinates corresponding to the vertex data; and drawing the section of the underground space according to the vertex data, the vertex sequence and the corresponding texture coordinates of the geometric mesh.

2. The method of claim 1, wherein, In a three-dimensional scene, terrain boundary sampling points and building boundary sampling points of the underground space are acquired, comprising: In the three-dimensional scene, three-dimensional terrain elements and building elements of the underground space are identified; ray detection is performed on the three-dimensional terrain elements to acquire the terrain boundary sampling points; ray detection is performed on the building elements of the underground space to acquire the building boundary sampling points of the underground space.

3. The method of claim 1, wherein, According to the building boundary sampling points of the underground space, the building boundary line of the underground space is acquired, comprising: The building boundary sampling points of the underground space are classified according to building types to acquire at least one building island discrete point set of the building; a convex hull algorithm is used to perform boundary line extraction processing on each building island discrete point set to obtain a building boundary line of each building in the underground space.

4. An apparatus for three-dimensional subsurface space visualization, characterized by The method comprises the following steps: a sampling point acquisition module is configured to acquire terrain boundary sampling points and building boundary sampling points of the underground space in a three-dimensional scene; a boundary line acquisition module is configured to acquire an outer boundary line at a section of the underground space according to the terrain boundary sampling points, and acquire a building boundary line according to the building boundary sampling points of the underground space; a section acquisition module is configured to acquire the section of the underground space according to the outer boundary line at the section and the building boundary line; a display module is configured to load and display the section of the underground space by a preset three-dimensional engine. In the method, after the terrain boundary sampling points are acquired, the following steps are further included: determining that a terrain corresponding to the terrain boundary sampling point is a hollow in a case that an elevation of the terrain boundary sampling point is invalid; and supplementing the terrain boundary sampling points corresponding to the terrain hollow in a difference manner in a case that the terrain is the hollow. The boundary line acquisition module is configured to acquire the outer boundary line at the section of the underground space according to the terrain boundary sampling points by using a convex hull algorithm to perform a boundary line extraction process on the terrain boundary sampling points. The section acquisition module is configured to acquire the section of the underground space according to the outer boundary line at the section and the building boundary line by using a triangulation algorithm to perform a geometric mesh construction process on the outer boundary line at the section and the building boundary line, to obtain vertex data and a vertex sequence of a geometric mesh corresponding to the section of the underground space, to acquire texture coordinates corresponding to the vertex data, and to draw the section of the underground space according to the vertex data, the vertex sequence, and the corresponding texture coordinates.

5. An apparatus for three-dimensional subsurface space visualization, comprising a processor and a memory having stored program instructions, characterized in that, The processor is configured to execute the method for visualizing a three-dimensional underground space according to any one of claims 1 to 3 when the program instructions are executed.

6. A computer, characterized by The device for visualizing a three-dimensional underground space according to claim 4 or 5.

7. A storage medium storing program instructions, characterized in that, The program instructions are configured to execute the method for visualizing a three-dimensional underground space according to any one of claims 1 to 3 when executed.

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