CN117807689B

CN117807689B - Building engineering data processing method and system based on BIM

Info

Publication number: CN117807689B
Application number: CN202410231509.0A
Authority: CN
Inventors: 王清文
Original assignee: Yantai University
Current assignee: Yantai University
Priority date: 2024-03-01
Filing date: 2024-03-01
Publication date: 2024-04-30
Anticipated expiration: 2044-03-01
Also published as: CN117807689A

Abstract

The invention discloses a building engineering data processing method and a system based on BIM, which firstly carry out folding operation on a BIM model based on folding errors, thereby completing geometric simplification of the BIM model, so that one-time light weight of the model can be completed on the premise of ensuring quality, and simultaneously, after one-time simplification is completed, triangular grids of the same material in the model are combined according to material information in the model, and thus, secondary simplification of the model is completed, and based on the two-time light weight of the model, the data quantity of the model can be further reduced; therefore, through the two simplified operations, the invention can greatly reduce the data quantity and the volume of the model on the basis of ensuring the quality of the model, thereby accelerating the loading speed of the model during interactive display, improving the browsing fluency and further ensuring the browsing experience of users.

Description

Building engineering data processing method and system based on BIM

Technical Field

The invention belongs to the technical field of engineering data processing, and particularly relates to a building engineering data processing method and system based on BIM.

Background

Along with the development of economic technology, various engineering constructions in China, such as railway, highway, residence, hydropower, traffic and other building engineering, have the characteristics of large construction scale, long period and wide range, have time and space differences and different engineering conditions in different positions and different construction periods, so that BIM models (Building Information Modeling and building information models) are mostly needed for carrying out mutual coordination among engineering design, construction, management and operation and maintenance, and further realize the management of the whole life cycle of the engineering.

The BIM technology has the visual advantage of 'what you see is what you get', and simultaneously has the characteristics of harmony, simulability, optimality, integrality and the like; therefore, the BIM technology is used for carrying out three-dimensional modeling on the building engineering, the data information of the whole life cycle of the engineering project can be stored in a computer to realize cooperation and sharing, and the method can be applied to project planning, engineering construction simulation, operation and maintenance management and other stages, and can effectively improve the construction level and operation and maintenance level of the whole project.

However, because the BIM model integrates various information of the building, such as information of geometry, spatial relationship, quantity, attribute and the like, the body volume of the model is huge, meanwhile, along with the continuous improvement of data acquisition precision and modeling technology, the precision of the BIM model is higher and higher, and the data volume is also increased rapidly, so that the data volume of the model is further increased; therefore, when the BIM model is actually interactively displayed, the phenomena of slow loading speed, stuck browsing process, even breakdown and the like are caused, so that the use experience of a user is extremely poor; based on the above, how to provide a BIM construction engineering data processing method with fast loading speed, smooth browsing and good user experience has become a problem to be solved urgently.

Disclosure of Invention

The invention aims to provide a building engineering data processing method and system based on BIM, which are used for solving the problems of slow model loading speed, browsing blocking and even breakdown caused by overlarge BIM model data volume in the prior art.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

In a first aspect, a building engineering data processing method based on BIM is provided, including:

acquiring a BIM model of a target building, and analyzing the BIM model to obtain material information and all triangular patches in the BIM model;

Determining a folding error influence factor of each triangular patch according to each triangular patch and the triangular patches adjacent to each triangular patch, wherein the triangular patch adjacent to any triangular patch is the triangular patch with at least one common vertex with any triangular patch in the BIM model;

Calculating the folding error of each triangular patch based on the folding error influence factor corresponding to each triangular patch, and carrying out folding operation on the BIM model according to the folding error of each triangular patch until the folding stop condition is met, so as to obtain an initial simplified BIM model;

According to the material information, performing material rendering on the initial simplified BIM model to obtain a simplified rendering BIM model;

extracting triangular grids of each component and material information corresponding to each triangular grid from the simplified rendering BIM model, and constructing a triangular grid set of the target building by utilizing the triangular grids of each component;

According to the material information of each triangular grid in the triangular grid set, carrying out grid division on the triangular grid set so as to divide the triangular grids with the same material information in the triangular grid set into the same class of clusters, and obtaining a plurality of triangular grid class clusters;

carrying out grid merging processing on the triangular grids in each triangular grid cluster to obtain merged grids corresponding to each triangular grid cluster;

and generating a light BIM model corresponding to the target building by utilizing the multiple merging grids, and performing model rendering on the light BIM model to finish light loading of the target building.

Based on the above disclosure, the present invention simplifies the model twice before loading the model to reduce the volume of the model, wherein the first simplification process is as follows: analyzing the model to obtain material information and all triangular patches in the BIM model, and calculating folding error influence factors of the triangular patches according to the triangular patches and the corresponding adjacent triangular patches; and then, based on the folding error influence factors of the triangular patches, obtaining the folding errors of the triangular patches, and based on the folding errors, performing folding operation of the BIM model, so that the first simplification of the model can be completed, and the initial simplified BIM model is obtained.

After the first simplification is completed, the second simplification can be performed, namely, firstly, the material rendering is performed on the initial simplified BIM model according to the analyzed material information, so as to obtain a simplified rendering initial model; then, extracting triangular grids of all components in the simplified rendering initial model, and forming a triangular grid set by utilizing the extracted triangular grids; then, the triangular grids belonging to the same material information can be divided into one type, and the triangular grids of the same type are combined to obtain a plurality of combined grids; therefore, the operation is equivalent to the combination of the grids of the same material in the model after one-time simplification, so that the data volume of the model can be further reduced; based on the above, a lightweight BIM model corresponding to the target building can be generated based on each merging grid; finally, the light loading of the target building can be completed by rendering the light BIM model.

Through the design, the folding operation is performed on the BIM model based on the folding error, so that the geometric simplification of the BIM model is completed, the primary light weight of the model can be completed on the premise of ensuring the quality, meanwhile, after the primary simplification is completed, the triangular grids of the same material in the model are combined according to the material information in the model, and the secondary simplification of the model is completed, so that the data size of the model can be further reduced; therefore, through the two simplified operations, the invention can greatly reduce the data quantity and the volume of the model on the basis of ensuring the quality of the model, thereby accelerating the loading speed of the model during interactive display, improving the browsing fluency and further ensuring the browsing experience of users.

In one possible design, determining the folding error impact factor of each triangular patch according to each triangular patch and the triangular patches adjacent to each triangular patch includes:

for any triangular patch, acquiring the area of each triangular patch adjacent to the any triangular patch, and calculating a neighborhood area influence factor of the any triangular patch based on the acquired area of each triangular patch;

Calculating a first normal vector of any triangular patch and a second normal vector of each triangular patch adjacent to the any triangular patch, and calculating a neighborhood curvature influence factor of the any triangular patch based on the first normal vector and each second normal vector;

Sequentially marking three vertexes of any triangular patch according to a clockwise direction, and sequentially marking three vertexes of each triangular patch adjacent to the any triangular patch to obtain a first marked triangular patch corresponding to the any triangular patch and a second marked triangular patch corresponding to each triangular patch adjacent to the any triangular patch;

Acquiring importance of each vertex in the first mark triangle patch and each second mark triangle patch, and calculating a vertex importance influence factor of any triangle patch based on the acquired importance of each vertex;

And forming the folding error influence factor of any triangular patch by using the neighborhood area influence factor, the neighborhood curvature influence factor and the vertex importance influence factor of any triangular patch.

In one possible design, calculating the neighborhood area impact factor of any triangular patch based on the obtained area of each triangular patch includes:

calculating a neighborhood area influence factor of any triangular patch according to the following formula (1) based on the area of each obtained triangular patch;

（1）

in the above-mentioned formula (1), Representing a neighborhood area impact factor of any triangle patch,/>Represents the/>, of all triangular patches adjacent to any one triangular patchArea of triangular patch,/>Representing the total number of adjacent triangular patches of the any triangular patch;

the calculating the neighborhood curvature influence factor of any triangle patch based on the first normal vector and each second normal vector includes:

Calculating a neighborhood curvature influence factor of any triangular patch according to the following formula (2);

（2）

In the above-mentioned formula (2), Representing a neighborhood curvature influence factor of said arbitrary triangle patch,/>Representing a first normal vector of said arbitrary triangle patch,/>Represents the/>, of all triangular patches adjacent to any one triangular patchSecond normal vector of triangular patches,/>Representing an inverse cosine function.

In one possible design, calculating the vertex importance influence factor of any triangle patch based on the obtained importance of each vertex includes:

according to the acquired importance of each vertex, calculating the vertex importance influence factor of any triangle patch according to the following formula (3);

（3）

In the above-mentioned formula (3), Representing the vertex importance influence factor of any triangle patch,/>Representing the importance of the vertex marked m in the first marked triangle patch,/>Representing the importance of the vertex labeled m in the ith second labeled triangular patch,/>Representing the importance of the vertex marked as e in the first marked triangle patch,/>Representing the importance of the vertex labeled e in the ith second labeled triangular patch,/>Representing the importance of the vertex marked k in the first marked triangle patch,/>Representing the importance of the vertex labeled k in the ith second labeled triangle patch,/>Representing the sum of the numbers of all the second marked triangular patches and the first marked triangular patches,/>Representing the total number of triangular patches adjacent to any one triangular patch.

In one possible design, the folding error impact factor of any triangular patch includes: the neighborhood area influence factor, neighborhood curvature influence factor and vertex importance influence factor of any triangle patch, wherein, based on the folding error influence factor corresponding to each triangle patch, the folding error of each triangle patch is calculated, including:

for any triangular patch, acquiring a plane equation of the any triangular patch, and calculating an initial error matrix of the any triangular patch based on the plane equation;

based on the initial error matrix and the folding error influence factor of any triangular patch, calculating an optimal error matrix of any triangular patch according to the following formula (4);

（4）

In the above-mentioned formula (4), Representing the optimal error matrix,/>Representing the vertex importance influence factor of any triangle patch,/>Representing a neighborhood curvature influence factor of said arbitrary triangle patch,/>Representing a neighborhood area impact factor of any triangle patch,/>Representing the initial error matrix;

and calculating the folding error of any triangular patch based on the optimal error matrix.

In one possible design, calculating the folding error of the arbitrary triangle patch based on the optimal error matrix includes:

Determining the folding point coordinates of any triangular patch by using the optimal error matrix;

and calculating the folding error of any triangular patch according to the folding point coordinates and the optimal error matrix.

In one possible design, performing a mesh merging process on the triangular meshes in each triangular mesh cluster to obtain a merged mesh corresponding to each triangular mesh cluster, where the mesh merging process includes:

For any triangular mesh cluster, constructing a bounding box of each triangular mesh in the any triangular mesh cluster;

combining the bounding boxes of all triangular grids in any triangular grid cluster to obtain a scene bounding box corresponding to the any triangular grid cluster;

Constructing an octree of any triangular mesh cluster based on the scene bounding box and the any triangular mesh cluster, wherein the octree comprises at least one leaf node, any leaf node comprises a plurality of triangular meshes, and each triangular mesh in the same leaf node is a triangular mesh with adjacent positions;

Combining triangular grids in each leaf node in the octree to obtain a plurality of combined sub-grids;

and obtaining the merging grids corresponding to any triangular grid class cluster based on the merging sub-grids.

In one possible design, constructing a bounding box of each triangle mesh in the any triangle mesh cluster includes:

For any triangular mesh in any triangular mesh cluster, combining three vertexes in any triangular mesh in pairs to obtain three vertex sets;

according to the coordinates of the two vertexes in each vertex set, calculating the correlation of the two vertexes in each vertex set;

Determining a bounding box main direction axis of any triangular mesh cluster based on coordinates of two vertexes with highest correlation;

and constructing a bounding box corresponding to any triangular mesh cluster by using the principal direction axis of the bounding box.

In one possible design, determining the principal direction axis of the bounding box of the any triangle mesh cluster based on the coordinates of the two vertices with highest correlation includes:

Constructing covariance matrixes of the two vertexes with the highest correlation according to the coordinates of the two vertexes with the highest correlation and the following formula (5);

（5）

In the above-mentioned formula (5), Representing covariance matrix,/>Representing the abscissa, ordinate and z-axis of one of the two vertices of highest relevance,/>Representing the abscissa, ordinate and z-axis coordinates of the other of the two vertices of highest relevance,/>Representing a covariance function;

diagonalizing the covariance matrix to obtain a diagonal matrix;

And calculating the eigenvectors of the diagonal matrix, and determining the principal direction axis of the bounding box of any triangular mesh cluster based on the eigenvectors.

In a second aspect, there is provided a building engineering data processing system based on BIM, comprising:

the acquisition unit is used for acquiring a BIM model of a target building, analyzing the BIM model and obtaining material information and all triangular patches in the BIM model;

The first light weight unit is used for determining folding error influence factors of all the triangular patches according to the triangular patches and the triangular patches adjacent to the triangular patches, wherein the triangular patches adjacent to any triangular patch are triangular patches with at least one common vertex with any triangular patch in the BIM model;

The first light weight unit is further used for calculating the folding error of each triangular patch based on the folding error influence factor corresponding to each triangular patch, and carrying out folding operation on the BIM model according to the folding error of each triangular patch until the folding stop condition is met, so as to obtain an initial simplified BIM model;

The rendering unit is used for rendering the material of the initial simplified BIM model according to the material information so as to obtain a simplified rendering BIM model;

The second light-weight unit is used for extracting triangular grids of each component and material information corresponding to each triangular grid from the simplified rendering BIM model, and constructing a triangular grid set of the target building by utilizing the triangular grids of each component;

The second light-weight unit is used for carrying out grid division on the triangular grid set according to the material information of each triangular grid in the triangular grid set so as to divide the triangular grids with the same material information in the triangular grid set into the same class of clusters to obtain a plurality of triangular grid class clusters;

The second light-weight unit is further used for carrying out grid merging processing on the triangular grids in each triangular grid cluster to obtain merged grids corresponding to each triangular grid cluster;

the model loading unit is used for generating a light BIM model corresponding to the target building by utilizing the multiple merging grids, and performing model rendering on the light BIM model so as to finish the light loading of the target building.

In a third aspect, a building engineering data processing device based on BIM is provided, taking the device as an electronic device, and the device includes a memory, a processor and a transceiver, which are sequentially connected in communication, where the memory is used to store a computer program, the transceiver is used to send and receive a message, and the processor is used to read the computer program, and execute the building engineering data processing method based on BIM as in the first aspect or any one of the first aspects.

In a fourth aspect, a storage medium is provided, on which instructions are stored which, when run on a computer, perform the building engineering data processing method based on BIM as in the first aspect or any one of the possible designs of the first aspect.

In a fifth aspect, there is provided a computer program product comprising instructions which, when run on a computer, cause the computer to perform the building engineering data processing method based on BIM as claimed in the first aspect or any one of the possible designs of the first aspect.

The beneficial effects are that:

(1) The invention firstly carries out folding operation on the BIM model based on folding errors, thereby completing geometric simplification of the BIM model, thus completing one-time light weight of the model on the premise of ensuring quality, and simultaneously merging triangular grids of the same material in the model according to material information in the model after completing one-time simplification, thereby completing secondary simplification of the model, and further reducing the data volume of the model based on the two-time light weight model; therefore, through the two simplified operations, the invention can greatly reduce the data quantity and the volume of the model on the basis of ensuring the quality of the model, thereby accelerating the loading speed of the model during interactive display, improving the browsing fluency and further ensuring the browsing experience of users.

Drawings

FIG. 1 is a schematic flow chart of steps of a BIM-based construction engineering data processing method according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a BIM-based construction engineering data processing system according to an embodiment of the present invention;

Fig. 3 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be briefly described below with reference to the accompanying drawings and the description of the embodiments or the prior art, and it is obvious that the following description of the structure of the drawings is only some embodiments of the present invention, and other drawings can be obtained according to these drawings without inventive effort to a person skilled in the art. It should be noted that the description of these examples is for aiding in understanding the present invention, but is not intended to limit the present invention.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments of the present invention.

It should be understood that for the term "and/or" that may appear herein, it is merely one association relationship that describes an associated object, meaning that there may be three relationships, e.g., a and/or B, may represent: a alone, B alone, and both a and B; for the term "/and" that may appear herein, which is descriptive of another associative object relationship, it means that there may be two relationships, e.g., a/and B, it may be expressed that: a alone, a alone and B alone; in addition, for the character "/" that may appear herein, it is generally indicated that the context associated object is an "or" relationship.

Examples:

Referring to fig. 1, in the building engineering data processing method based on BIM provided in this embodiment, geometric simplification is performed on a BIM model of a target building based on a folding error, so as to obtain a simplified model; then merging triangular grids of the same material in the model after the primary simplification according to the material information in the model after the primary simplification; thus, the data volume of the model can be further reduced; therefore, the method can greatly reduce the data volume of the model on the basis of ensuring the quality of the model, so that the loading speed of the model can be increased during interactive display, the browsing fluency can be improved, and the browsing experience of a user can be further ensured, and therefore, the method is very suitable for large-scale application and popularization in the field of data processing of building engineering; the method may be performed on the model display end, alternatively, the model display end may be performed by a personal computer, and it is to be understood that the foregoing execution subject is not limited to the embodiment of the present application, and accordingly, the operation steps of the method may be performed by the following steps S1 to S8.

S1, acquiring a BIM model of a target building, and analyzing the BIM model to obtain material information and all triangular patches in the BIM model; in this embodiment, the BIM model may be converted into data in an IFC format, for example, so that based on the data in the IFC format (Industry Foundation Classes, an open data model and a file format, which are mainly used for information exchange in the field of building engineering), material information and three-dimensional geometric data in the BIM model are obtained, where the three-dimensional geometric data includes all triangle patches in the BIM model; of course, the data format conversion and the extraction process of the material and geometric data are common techniques used for analyzing the BIM model, and the principle thereof is not repeated.

After the analysis of the BIM model is completed, the BIM model can be subjected to light weight treatment, wherein the embodiment is provided with two light weight processes, namely, geometric simplification of the model is performed for the first time, and the same-material triangular mesh of the model is simplified for the second time; the first light-weight process may be, but is not limited to, as shown in the following steps S2 and S3.

S2, determining folding error influence factors of all triangular patches according to all triangular patches and the triangular patches adjacent to all the triangular patches, wherein the triangular patch adjacent to any triangular patch is the triangular patch with at least one common vertex with any triangular patch in the BIM model; in the embodiment, considering the influence of geometric simplification on model quality, a folding error influence factor is introduced, which mainly comprises a neighborhood area influence factor, a neighborhood curvature influence factor and a vertex importance influence factor; in this way, the error matrix is constructed corresponding to the area of the adjacent triangular patch, the curvature of the adjacent triangular patch, and the importance of the vertex, and the folding error is calculated.

Alternatively, this embodiment takes any triangular dough sheet as an example to specifically describe the construction process of the folding influencing factor, and may be, but not limited to, the following steps S21 to S25.

S21, for any triangular patch, acquiring the area of each triangular patch adjacent to the any triangular patch, and calculating a neighborhood area influence factor of the any triangular patch based on the area of each acquired triangular patch; in this embodiment, the side length of each triangular patch may be obtained according to the vertex coordinates of each triangular patch, and then the area may be calculated according to the side length; after the area of each triangle patch adjacent to any triangle patch is obtained, the neighborhood area influence factor may be calculated, where, for example, but not limited to, the following formula (1) may be used to calculate the neighborhood area influence factor.

（1）

In the above-mentioned formula (1),Representing a neighborhood area impact factor of any triangle patch,/>Represents the/>, of all triangular patches adjacent to any one triangular patchArea of triangular patch,/>Representing the total number of triangular patches adjacent to any one triangular patch.

Based on the above formula (1), the neighbor area influence factor is substantially the average area of all adjacent triangular patches of any triangular patch; after calculating the domain area influence factor of any triangle, the neighborhood curvature influence factor may be calculated, and the calculation process may be, but is not limited to, the following step S22.

S22, calculating a first normal vector of any triangular patch and a second normal vector of each triangular patch adjacent to the any triangular patch, and calculating a neighborhood curvature influence factor of the any triangular patch based on the first normal vector and each second normal vector; in particular implementations, the neighborhood curvature impact factor of any triangular patch may be calculated, for example, but not limited to, using equation (2) below.

（2）

In the above-mentioned formula (2),Representing a neighborhood curvature influence factor of said arbitrary triangle patch,/>Representing a first normal vector of said arbitrary triangle patch,/>Represents the/>, of all triangular patches adjacent to any one triangular patchSecond normal vector of triangular patches,/>Representing an inverse cosine function.

Based on the formula (2), calculating a neighborhood curvature influence factor of any triangle patch, and then calculating a vertex importance influence factor; wherein the calculation process is as follows in step S23 and step S24.

S23, sequentially marking three vertexes of any triangular surface patch according to a clockwise direction, and sequentially marking three vertexes of each triangular surface patch adjacent to the any triangular surface patch to obtain a first marked triangular surface patch corresponding to the any triangular surface patch and a second marked triangular surface patch corresponding to each triangular surface patch adjacent to the any triangular surface patch; in specific implementation, vertex identification of the triangular patches can be performed by taking the clockwise 12-point direction as a starting point, and the identification can be but not limited to adopting numbers or letters, meanwhile, the identification of any triangular patch and each adjacent triangular patch is the same, for example, the first vertex after the clockwise 12-point direction is marked with 1, the second vertex is marked with 2, the third vertex is marked with 3, and the like; thus, the vertex mark of any triangle face sheet and the corresponding adjacent triangle face sheets can be completed, thereby obtaining a first mark triangle face sheet and a plurality of second mark triangle face sheets,

Then, the calculation of the vertex importance influence factor may be performed based on the vertex importance of each labeled triangle patch, and the calculation process may be, but not limited to, the following step S24.

S24, obtaining importance of each vertex in the first mark triangle patch and each second mark triangle patch, and calculating a vertex importance influence factor of any triangle patch based on the obtained importance of each vertex; in specific application, taking any vertex of the first label triangle patch as an example, the importance calculating process of any vertex is specifically described.

Specifically, the method comprises the following steps: (1) Calculating a first plane normal vector of a target triangular patch, wherein the target triangular patch is a second identification triangular patch connected with any vertex; (2) Calculating the average normal vector of all the first plane normal vectors, and taking the average normal vector as the normal vector of any vertex; (3) Based on the normal vector of any vertex and each first plane normal vector, calculating the importance of each target triangle patch by adopting the following formula (6); (4) The importance of any one of the vertices is calculated based on the patch importance of each target triangle patch according to the following formula (7).

（6）

In the above-mentioned formula (6),Represents the/>Patch importance of each target triangle patch,/>Representing the normal vector of any vertex,/>Represents the/>A first planar normal vector of each target triangular patch.

（7）

In the above-mentioned formula (7),Representing the importance of any vertexRepresenting an upward rounding function,/>The importance parameter is represented, the value is 0-1, and L represents the total number of the target triangle patches.

Calculating the importance of each vertex of the first label triangle patch and each vertex of the second label triangle patch based on the steps (1) - (4), and then calculating the influence factor of the importance of the vertex; wherein, for example but not limited to, according to the following formula (3), the vertex importance influence factor of any triangle patch is calculated;

（3）

In the above-mentioned formula (3), Representing the vertex importance influence factor of any triangle patch,/>Representing the importance of the vertex marked m in the first marked triangle patch,/>Representing the importance of the vertex labeled m in the ith second labeled triangular patch,/>Representing the importance of the vertex marked as e in the first marked triangle patch,/>Representing the importance of the vertex labeled e in the ith second labeled triangular patch,/>Representing the importance of the vertex marked k in the first marked triangle patch,/>Representing the importance of the vertex labeled k in the ith second labeled triangle patch,/>Representing the sum of the numbers of all the second marked triangular patches and the first marked triangular patches,/>Representing the total number of triangular patches adjacent to the any triangular patch (i.e., the total number of second identified triangular patches).

In this embodiment, the foregoing formula (3) is illustrated by way of example, assuming that the vertex identifications are numbered 1,2,3, i.e., m=1, e=2, k=3, respectively, then,Representing the importance of the vertex marked as1 in the first marked triangle patch,/>Representing the importance of the vertex labeled 1 in the ith second labeled triangular patch,/>Representing the importance of vertex marked as 2 in the first marked triangle patch,/>Representing the importance of the vertex labeled 2 in the ith second labeled triangular patch,/>Representing importance corresponding to the vertex marked as 3 in the ith second marked triangle patch; thus, the above formula is equivalent to summing the importance of the same vertices, and then averaging to obtain the vertex importance influence factor of any triangle patch.

After the vertex importance influence factor, the neighborhood area influence factor and the neighborhood curvature influence factor of any triangle patch are calculated, the three factors can be utilized to form the folding error influence factor of any triangle patch, and the construction process is shown in the following step S25.

S25, utilizing the neighborhood area influence factor, the neighborhood curvature influence factor and the vertex importance influence factor of any triangular patch to form the folding error influence factor of any triangular patch.

Therefore, three influencing factors can be introduced through the steps S21 to S25 to improve the precision of the folding error calculation, wherein the curvature can represent local characteristics, namely, the triangular patches are distributed densely, the area of the local area is small, the curvature is large, the fact that a curved surface characteristic area exists in the area of the model is indicated, the focus is reserved, namely, the larger the neighborhood curvature influencing factor is, the fact that detail characteristics exist in the area where any triangular patch exists is indicated, the weight of the area is reduced, and otherwise, the weight is required to be preferentially reduced; thus, through the design, the precision of folding errors can be improved, and the quality of the BIM model in geometric simplification is improved.

After the folding error influence factors of the triangular patches are obtained, the folding error can be calculated based on the folding error influence factors, and then the geometric weight of the model can be reduced based on the folding error; the foregoing process may be, but is not limited to, as shown in step S3 below.

S3, based on folding error influence factors corresponding to the triangular patches, calculating folding errors of the triangular patches, and carrying out folding operation on the BIM model according to the folding errors of the triangular patches until folding stop conditions are met, so as to obtain an initial simplified BIM model; in the specific implementation, a specific calculation process of the folding error is specifically described by taking any triangular dough sheet as an example, and may be, but not limited to, the following steps S31 to S33.

S31, for any triangular patch, acquiring a plane equation of the any triangular patch, and calculating an initial error matrix of the any triangular patch based on the plane equation; in this embodiment, the plane equation of any of the triangular patches described above can be defined as: wherein/> Represents the intercept in the x, y and z axes, d is a constant, and/>Then, the initial error matrix may be expressed as:

after the initial error matrix is calculated, the calculation of the optimal error matrix can be performed by combining the folding error influencing factors of any of the triangular patches, and the calculation process is as follows in step S32.

S32, calculating an optimal error matrix of any triangular patch according to the following formula (4) based on the initial error matrix and the folding error influence factor of any triangular patch.

（4）

In the above-mentioned formula (4),Representing the optimal error matrix,/>Representing the vertex importance influence factor of any triangle patch,/>Representing a neighborhood curvature influence factor of said arbitrary triangle patch,/>Representing a neighborhood area impact factor of any triangle patch,/>Representing the initial error matrix.

After calculating the optimal error matrix of any one of the triangular patches based on the above formula (4), the folding error of any one of the triangular patches can be calculated based on the optimal error matrix, and the calculation process is as follows in step S33.

S33, calculating the folding error of any triangular patch based on the optimal error matrix; in specific applications, for example, but not limited to, the optimal error matrix is utilized first to determine the coordinates of the folding points of any triangular patch; and then, according to the folding point coordinates and the optimal error matrix, calculating the folding error of any triangular patch.

In the present embodiment, the folding point coordinates are set asThen the fold point coordinates may be determined using, but not limited to, equation (8) below.

（8）

In the above formula (8), the first three rows of elements in the matrix are the first three rows of elements in the optimal error matrix, and thus, the folding point coordinates can be obtained by solving the formula (8); then, the following formula (9) can be used to calculate the folding error of any triangular patch.

（9）

In the above-mentioned formula (9),Indicating the folding error of any of the triangular panels.

Thus, the folding error of each triangular patch can be calculated through the foregoing steps S31 to S33, and then, the folding operation of the BIM model can be performed based on the folding error of each triangular patch, wherein the procedure is as follows.

The first step: sequencing all the triangular patches in the BIM according to the sequence of the folding errors from small to large; and a second step of: selecting the triangular surface patches with the first sequence as the surface patches to be folded, and performing triangular folding operation; and a third step of: repeating the first step and the second step until the folding stop condition is met; in this embodiment, the folding stop condition may be, but is not limited to, that the simplified model data amount reaches a preset value, or that the number of folded faces is equal to or less than a threshold value; of course, the triangle folding operation is a common method for light weight of the BIM model, and the principle thereof is not described again.

Thus, after the geometric weight reduction process of the BIM model is completed in the above step S3, the secondary weight reduction process may be performed, but the process is not limited to the following steps S4 to S7.

S4, according to the material information, rendering the material of the initial simplified BIM model to obtain a simplified rendering BIM model; in this embodiment, the material giving operation is equivalent to that of the initial simplified BIM model, so as to obtain a simplified rendering BIM model; then, the merging of the grids of the same material in the simplified rendering BIM model can be performed, and the processing procedure is as follows in steps S5 to S7.

S5, extracting triangular grids of all the components and material information corresponding to each triangular grid from the simplified rendering BIM model, and constructing a triangular grid set of the target building by utilizing the triangular grids of all the components; in this embodiment, one member in the simplified rendering BIM model (the member is a basic component unit of the BIM model, and may represent any building element such as a wall, a beam, a column, a door or window) is formed by one or more triangular meshes, so step S5 is equivalent to extracting the triangular meshes that form each member, and thus a triangular mesh set is constructed; then, the triangle mesh set may be clustered to complete the division of the same material mesh, where the clustering process is as follows in step S6.

S6, according to the material information of each triangular grid in the triangular grid set, carrying out grid division on the triangular grid set so as to divide the triangular grids with the same material information in the triangular grid set into the same class of clusters, and obtaining a plurality of triangular grid class clusters; in a specific implementation, triangular meshes having the same material are classified into one type, so that the merging process of the same material meshes is performed later, where the merging process is as follows in step S7.

S7, carrying out grid combination treatment on the triangular grids in each triangular grid cluster to obtain a combined grid corresponding to each triangular grid cluster; in specific applications, any triangle mesh cluster is taken as an example to specifically describe the mesh merging process, and the following steps S71 to S75 can be adopted but are not limited to the description.

S71, constructing a bounding box of each triangular mesh in any triangular mesh cluster; in this embodiment, the construction of the bounding box is performed based on the vertex coordinates of each triangular mesh in any of the triangular mesh clusters, and the process is specifically described by taking any of the triangular meshes in any of the triangular mesh clusters as an example, but the process is not limited to the following steps S71a to S71 d.

S71a, combining three vertexes in any triangular mesh class cluster in pairs to obtain three vertex sets; in this embodiment, assuming that three vertices of any triangular mesh are point a, point B, and point C in sequence, then three vertex sets are AC, AB, and BC; after the three vertex sets are obtained, the correlation between every two vertices in each vertex set is calculated, as shown in step S71 b.

S71b, calculating the correlation of the two vertexes in each vertex set according to the coordinates of the two vertexes in each vertex set; in specific application, for any vertex set, calculating the coordinate covariance of two vertices in the any vertex set to obtain the correlation of the two vertices in the any vertex set; after obtaining the correlation between the two vertices in each vertex set, the two vertices with the highest correlation may be used to determine the principal direction axis of the bounding box of any triangle mesh cluster, which is shown in step S71c below.

S71c, determining a principal direction axis of a bounding box of any triangular mesh cluster based on coordinates of two vertexes with highest correlation; in specific applications, the following steps S71c1 to S71c3 may be used, for example and without limitation, to determine the principal direction axis of the bounding box of any triangle mesh cluster.

S71c1, constructing a covariance matrix of the two vertexes with the highest correlation according to the coordinates of the two vertexes with the highest correlation and the following formula (5).

（5）

In the above-mentioned formula (5),Representing covariance matrix,/>Representing the abscissa, ordinate and z-axis of one of the two vertices of highest relevance,/>Representing the abscissa, ordinate and z-axis coordinates of the other of the two vertices of highest relevance,/>Representing the covariance function.

After calculating the covariance matrix of the two vertices with the highest correlation based on the above formula (5), the principal direction axis of the bounding box of any triangle mesh cluster can be determined based on the covariance matrix, as shown in step S71c2 and step S71c3 below.

And S71c2, diagonalizing the covariance matrix to obtain a diagonal matrix.

S71c3, calculating a feature vector of the diagonal matrix, and determining a principal direction axis of a bounding box of any triangular mesh cluster based on the feature vector; in this embodiment, the feature vector may be directly used as the bounding box main direction axis.

In addition, in the present embodiment, the covariance matrix corresponding to the formula (5) may be constructed by using the covariance of two vertices in any vertex set in the step S71b, and the maximum eigenvalue is obtained by calculating the eigenvalue, and then the maximum eigenvalue is used as the correlation metric value.

After determining the principal axis of the bounding box of any one of the triangular mesh clusters in steps S71c1 to S71c3, the bounding box of any one of the triangular mesh clusters can be constructed based on the principal axis, as shown in step S71d below.

S71d, constructing a bounding box corresponding to any triangular mesh cluster by utilizing the principal direction axis of the bounding box; in this embodiment, an OBB bounding box construction algorithm may be used to construct an OBB bounding box (Oriented Bounding Box, directed bounding box) corresponding to the arbitrary triangle mesh cluster; of course, the construction method of the OBB bounding box belongs to a common technology in the field of bounding box construction, and the principle thereof is not described in detail.

Thus, after the bounding boxes of the triangular meshes in any one of the triangular mesh clusters are constructed in the steps S71a to S71d, the bounding boxes can be combined as shown in the following step S72.

S72, merging bounding boxes of all triangular grids in any triangular grid cluster to obtain a scene bounding box corresponding to the any triangular grid cluster; after completing the merging of bounding boxes of each triangular mesh based on the aforementioned step S72, the construction of the octree corresponding to any one of the triangular mesh clusters may be performed based on the merged bounding box (i.e., scene bounding box), where the construction process may be, but is not limited to, as shown in the following step S73.

S73, constructing an octree of any triangular grid cluster based on the scene bounding box and the any triangular grid cluster, wherein the octree comprises at least one leaf node, any leaf node comprises a plurality of triangular grids, and each triangular grid in the same leaf node is a triangular grid with adjacent positions; when the method is specifically applied, the scene bounding box is used as a space range, and the octree is created in the space range, so that adjacent triangular grids in any triangular grid cluster can be divided into a subspace (namely leaf nodes) by utilizing the octree, and the combination of adjacent triangular grids with the same material quality is realized; namely, a plurality of subspaces exist in the octree, and the subspace of each triangular mesh is judged through the vertex coordinates of the triangular mesh, so that the triangular mesh belonging to the same subspace is divided into one type to be used as the mesh of a leaf node; if so, the grids which are close to each other can be combined into a large grid according to the space positions of the grids, so that the combination of grids with the same material quality is realized; in this embodiment, if there is an independent mesh in any triangle mesh cluster, that is, it is not adjacent to any mesh, it is not inserted into the octree, and it is used as a single mesh.

After the construction of the octree corresponding to any one of the triangular mesh clusters is completed based on the aforementioned step S73, mesh merging can be performed as shown in the following step S74.

S74, combining triangular grids in each leaf node in the octree to obtain a plurality of combined sub-grids; based on the step S74, the merging of adjacent grids in the grids of the same material can be completed, and then, each obtained merging sub-grid can be used as a merging grid corresponding to any triangular grid cluster, as shown in the following step S75.

S75, based on the multiple merging sub-grids, merging grids corresponding to any triangular grid class cluster are obtained.

Therefore, the merging of adjacent triangular grids in each triangular grid cluster can be completed through the steps S71-S75, so that the data volume of the model is further reduced; then, a plurality of merging grids can be utilized to generate a light BIM model of the target building; the process of generating the lightweight BIM model is shown in step S8.

S8, generating a light BIM model corresponding to the target building by utilizing a plurality of merging grids, and performing model rendering on the light BIM model to finish light loading of the target building; in this embodiment, the foregoing has described that there may be independent triangular meshes in each triangular mesh cluster, so when generating the lightweight BIM model, it is also necessary to add the independent triangular meshes, that is, to generate the lightweight BIM model of the target building by using the combined meshes (i.e., several combined sub-meshes) corresponding to each triangular mesh cluster and the remaining independent triangular meshes; in this embodiment, the principle of the conventional technology for building the BIM model based on the triangular mesh regeneration BIM model is not described in detail.

After the light weight processing of the BIM model of the target building is completed, the light weight BIM model can be loaded, the model is rendered when loaded, and output display is performed after rendering; thus, the lightweight loading of the target building can be completed.

Therefore, by the building engineering data processing method based on BIM described in detail in the steps S1 to S8, the invention firstly carries out geometric simplification on the BIM model of the target building based on folding errors to obtain a simplified model; then merging triangular grids of the same material in the model after the primary simplification according to the material information in the model after the primary simplification; thus, the data volume of the model can be further reduced; therefore, the method can greatly reduce the data volume of the model on the basis of ensuring the quality of the model, so that the model loading speed can be increased during interactive display, the browsing fluency can be improved, and the browsing experience of a user can be further ensured.

As shown in fig. 2, a second aspect of the present embodiment provides a hardware system for implementing the building engineering data processing method based on BIM in the first aspect of the present embodiment, including:

the acquisition unit is used for acquiring the BIM model of the target building, analyzing the BIM model and obtaining material information and all triangular patches in the BIM model.

The first light weight unit is used for determining folding error influence factors of all the triangular patches according to the triangular patches and the triangular patches adjacent to the triangular patches, wherein the triangular patches adjacent to any triangular patch are triangular patches with at least one common vertex with any triangular patch in the BIM model.

The first light weight unit is further used for calculating the folding error of each triangular patch based on the folding error influence factor corresponding to each triangular patch, and carrying out folding operation on the BIM model according to the folding error of each triangular patch until the folding stop condition is met, so that the initial simplified BIM model is obtained.

And the rendering unit is used for rendering the material of the initial simplified BIM model according to the material information so as to obtain a simplified rendering BIM model.

And the second light-weight unit is used for extracting triangular grids of each component and material information corresponding to each triangular grid from the simplified rendering BIM model, and constructing a triangular grid set of the target building by utilizing the triangular grids of each component.

And the second light-weight unit is used for carrying out grid division on the triangular grid set according to the material information of each triangular grid in the triangular grid set so as to divide the triangular grids with the same material information in the triangular grid set into the same class of clusters and obtain a plurality of triangular grid class clusters.

And the second light-weight unit is also used for carrying out grid merging processing on the triangular grids in each triangular grid cluster to obtain merged grids corresponding to each triangular grid cluster.

The working process, working details and technical effects of the system provided in this embodiment may refer to the first aspect of the embodiment, and are not described herein again.

As shown in fig. 3, a third aspect of the present embodiment provides a building engineering data processing apparatus based on BIM, taking the apparatus as an electronic device, including: the system comprises a memory, a processor and a transceiver which are connected in sequence in communication, wherein the memory is used for storing a computer program, the transceiver is used for receiving and transmitting messages, and the processor is used for reading the computer program and executing the building engineering data processing method based on BIM according to the first aspect of the embodiment.

By way of specific example, the Memory may include, but is not limited to, random access Memory (random access Memory, RAM), read Only Memory (ROM), flash Memory (Flash Memory), first-in-first-Out Memory (First Input First Output, FIFO) and/or first-in-last-Out Memory (FIRST IN LAST Out, FILO), and the like; in particular, the processor may include one or more processing cores, such as a 4-core processor, an 8-core processor, or the like. The processor may be implemented in at least one hardware form of DSP (DIGITAL SIGNAL Processing), FPGA (Field-Programmable gate array), PLA (Programmable Logic Array ), and may also include a main processor and a coprocessor, where the main processor is a processor for Processing data in a wake-up state, and is also called CPU (Central Processing Unit ); a coprocessor is a low-power processor for processing data in a standby state.

In some embodiments, the processor may be integrated with a GPU (Graphics Processing Unit, image processor) for rendering and drawing of content required to be displayed by the display screen, e.g., the processor may not be limited to a microprocessor of the STM32F105 family, a reduced instruction set computer (reduced instruction set computer, RISC) microprocessor, an X86 or other architecture processor, or a processor that integrates an embedded neural network processor (neural-network processing units, NPU); the transceiver may be, but is not limited to, a wireless fidelity (WIFI) wireless transceiver, a bluetooth wireless transceiver, a General Packet Radio Service (GPRS) wireless transceiver, a ZigBee wireless transceiver (low power local area network protocol based on the ieee802.15.4 standard), a 3G transceiver, a 4G transceiver, and/or a 5G transceiver, etc. In addition, the device may include, but is not limited to, a power module, a display screen, and other necessary components.

The working process, working details and technical effects of the electronic device provided in this embodiment may refer to the first aspect of the embodiment, and are not described herein again.

A fourth aspect of the present embodiment provides a storage medium storing instructions containing the building engineering data processing method based on the BIM according to the first aspect of the present embodiment, that is, the storage medium storing instructions thereon, when the instructions are executed on a computer, the building engineering data processing method based on the BIM according to the first aspect of the present embodiment is executed.

The storage medium refers to a carrier for storing data, and may include, but is not limited to, a floppy disk, an optical disk, a hard disk, a flash Memory, a flash disk, and/or a Memory Stick (Memory Stick), where the computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable devices.

The working process, working details and technical effects of the storage medium provided in this embodiment may refer to the first aspect of the embodiment, and are not described herein again.

A fifth aspect of the present embodiment provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the BIM-based construction data processing method of the first aspect of the embodiment, wherein the computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus.

Finally, it should be noted that: the foregoing description is only of the preferred embodiments of the invention and is not intended to limit the scope of the invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The building engineering data processing method based on BIM is characterized by comprising the following steps:

2. The method of claim 1, wherein determining the fold error impact factor for each triangular patch based on each triangular patch and each triangular patch adjacent to each triangular patch comprises:

3. The method of claim 2, wherein calculating a neighborhood area impact factor for any of the triangular patches based on the acquired area of each triangular patch comprises:

（1）

（2）

4. The method according to claim 2, wherein calculating the vertex importance influence factor of any one of the triangular patches based on the obtained importance of each vertex, comprises:

（3）

5. The method of claim 1, wherein the folding error impact factor for any triangular patch comprises: the neighborhood area influence factor, neighborhood curvature influence factor and vertex importance influence factor of any triangle patch, wherein, based on the folding error influence factor corresponding to each triangle patch, the folding error of each triangle patch is calculated, including:

（4）

6. The method of claim 5, wherein calculating the folding error of the arbitrary triangle patch based on the optimal error matrix comprises:

7. The method of claim 1, wherein performing mesh merging processing on the triangular meshes in each triangular mesh cluster to obtain a merged mesh corresponding to each triangular mesh cluster, comprises:

8. The method of claim 7, wherein constructing a bounding box for each triangle mesh in the any triangle mesh class cluster comprises:

9. The method of claim 8, wherein determining the bounding box principal direction axis of any one of the triangular mesh-like clusters based on coordinates of two vertices with highest correlation comprises:

（5）

diagonalizing the covariance matrix to obtain a diagonal matrix;

10. A building engineering data processing system based on BIM, comprising: