CN110726411B

CN110726411B - Indoor emergency path finding method of building information model based on subdivision grids

Info

Publication number: CN110726411B
Application number: CN201910933058.4A
Authority: CN
Inventors: 苗双喜; 程承旗; 陈波; 章煌创
Original assignee: Peking University
Current assignee: Peking University
Priority date: 2019-09-29
Filing date: 2019-09-29
Publication date: 2021-07-06
Anticipated expiration: 2039-09-29
Also published as: CN110726411A

Abstract

The invention discloses an indoor emergency path-finding method of a building information model based on a subdivision grid, relates to the technical field of building information models, and can realize the indoor multi-layer space path planning of a building in a three-dimensional space by taking the subdivision grid as a carrier. The technical scheme of the invention comprises the following steps: and (4) performing model analysis on BIM data of a building information model of the building to obtain coordinate information and attribute information of each part in the building. Replacing each part in the building by adopting a subdivision grid matched with the scale to obtain a grid map of the building; and performing passable judgment according to the attribute information corresponding to the subdivision grids, and setting passable marks for the subdivision grids. And acquiring information of a starting point and an end point, wherein the starting point and the end point are both positioned on a grid map of the building, and acquiring an optimal path between the starting point and the end point by adopting an A-path searching algorithm.

Description

Indoor emergency path finding method of building information model based on subdivision grids

Technical Field

The invention relates to the technical field of building information models, in particular to an indoor emergency path finding method of a building information model based on a subdivision grid.

Background

Along with the improvement of urban infrastructure and the continuous improvement of building coverage, the demand of the location information service based on the space in the building in each field of social production and life is increasingly urgent, especially in public buildings with people gathering, such as shopping malls, hospitals, high-rise office buildings, exhibition halls, underground garages and the like, people often need to know the position of the people and how to quickly reach designated shops, wards, offices, exhibition halls and vehicles, and besides, in the field of emergency rescue, the safe evacuation of people trapped in the building and the efficient rescue of fire fighters can not be supported by the indoor navigation technology. However, due to the complex structure of the internal space of the building, the high requirement for precision, and the weak signal of the conventional GPS and BDS based navigation positioning technology because the indoor is shielded by obstacles, the outdoor navigation technology cannot be directly applied to indoor navigation, and thus the development of the navigation technology for the indoor environment of the building occupying 70% -80% of the activity space of people in production and life is relatively slow.

The indoor path planning is used as the core of the indoor navigation service, and the indoor path planning, the indoor positioning technology and the space display technology together form a complete indoor navigation system, which is the premise and the basis for realizing the indoor navigation service and has different index requirements for different application scenes. Compared with the environment of roads outside buildings, users mainly using vehicles can only run on a planned road network, and the environment of rooms mainly using individuals can freely move in passable areas, for example, in a shopping mall, people can require to plan an optimal path according to their shopping demands, and when an emergency situation needs to escape, the path planning also needs to have corresponding flexibility according to different indoor environment changes due to changes of road damage, elevator unavailability and the like. For the application requirements of the deeper level, the indoor path should be adjusted correspondingly according to the passing authorities of different entrances and exits. Therefore, research on indoor path planning needs to comprehensively consider distribution of indoor obstacles, opening and closing states of room doors and abundant semantic information of indoor components, and also needs to consider physical connection of vertical stairs, escalators and the like between floors for path planning requirements across floors.

At present, the research of the indoor navigation path planning in China mainly focuses on relying on a two-dimensional plane building drawing, or relying on artificial measurement to draw an indoor map to find the shortest path, because of the lack of basic data information of a building, an indoor barrier entity cannot be considered, and the precision of the indoor map drawn by measurement is difficult to guarantee, so that a great number of errors exist in the path planning, the path is shortest but not optimal, in addition, because of the limitation of a two-dimensional plane expression form, the intuition and the practicability of the path expression can also be influenced, and a great number of limitations exist in the aspects of cross-floor path planning, barrier avoidance, three-dimensional interaction of the navigation path and the like in the building.

Therefore, a method for building indoor emergency road finding in a three-dimensional space is needed.

Disclosure of Invention

In view of the above, the invention provides an indoor emergency path-finding method for a building information model based on a split grid, which can realize the indoor multi-layer space path planning of a building in a three-dimensional space by using the split grid as a carrier.

In order to achieve the purpose, the technical scheme of the invention comprises the following steps:

and (4) performing model analysis on BIM data of a building information model of the building to obtain coordinate information and attribute information of each part in the building.

Replacing each part in the building by adopting a subdivision grid matched with the scale to obtain a grid map of the building; and performing passable judgment according to the attribute information corresponding to the subdivision grids, and setting passable marks for the subdivision grids.

And acquiring information of a starting point and an end point, wherein the starting point and the end point are both positioned on a grid map of the building, and acquiring an optimal path between the starting point and the end point by adopting an A-path searching algorithm.

Further, building information model BIM data of the building is taken for model analysis, and coordinate information and attribute information of each part in the building are obtained, specifically:

s101, building information model BIM data of a building are taken and converted into a GLTF file.

And S102, analyzing the GLTF file to obtain coordinate information and attribute information of each part in the building based on a Cartesian space rectangular coordinate system.

S103, converting the coordinate information of each component based on a Cartesian space rectangular coordinate system into the coordinate information of each component based on a national basic geographic coordinate system.

Further, the method comprises the following steps of taking BIM data of a building information model of a building, converting the BIM data into a GLTF file:

s1011, the BIM data of the building information model of the building is an FBX file; the FBX file is converted into an OBJ file.

And S1012, converting the OBJ file into a DAE file in an open source format.

S1013, converting the DAE file in the open source format into a GLTF file.

Further, each part in the building is replaced by a subdivision grid matched with the scale to obtain a grid map of the building, which specifically comprises the following steps:

and determining the hierarchy of the GeoSOT 3D split grid according to the size of the current component by adopting the GeoSOT 3D split grid, and taking the GeoSOT 3D split grid of the determined hierarchy as the split grid matched with the corresponding scale of the current component.

And (3) replacing all components in the building by adopting a subdivision grid matched with the scale of the components, thereby obtaining a grid map of the building.

Further, acquiring information of a starting point and an end point, wherein the starting point and the end point are both positioned on a grid map of the building to which the starting point and the end point belong, and acquiring an optimal path between the starting point and the end point by adopting an A-path searching algorithm; the method specifically comprises the following steps:

s1, establishing an expansion point list and a deletion point list, wherein the expansion point list is initially stored in a starting point, and the deletion point list is initially empty; taking the starting point as an initial value of the processing point; each subdivision grid in the grid map of the building is simplified into one point.

And S2, taking all the adjacent points of the processing points, traversing the deletion point list, taking all the adjacent points which are located in the deletion point list and can pass through the grid and do not exist in the deletion point list as undetermined extension points.

S3, calculating the value of a cost function F (n) by taking each undetermined expansion point as an intermediate point n, taking the undetermined expansion point corresponding to the minimum value of F (n) as an expansion point, and storing the expansion point into an expansion point list.

The cost function F (n) is the sum of the actual cost from the starting point to the intermediate point n and the estimated cost from the intermediate point n to the end point; the actual cost from the starting point to the intermediate point n is the Euclidean distance from the starting point to the intermediate point n, the estimated cost value range from the intermediate point n to the end point is [ a, b ], a is the Euclidean distance from the intermediate point n to the end point, and b is the Manhattan distance from the intermediate point n to the end point.

S4, if the adjacent points of the expansion point are not passable, storing the current expansion point into a deletion point list, and returning to S2; otherwise, the process returns to S2 with the extension point as the processing point.

If the expansion point list contains the terminal, finishing the A-path searching algorithm based on the grid, and taking the path formed by all the points in the expansion point list at the moment as the optimal path; otherwise, no passable path exists between the starting point and the end point.

Has the advantages that:

according to the indoor emergency path finding method of the building information model based on the subdivision grids, provided by the invention, information such as coordinates of each part in the building is obtained by analyzing the BIM model; combining the subdivision grid codes to generate a grid map of the whole building; and then, performing indoor emergency accurate path-finding planning based on the A-x algorithm of the grid to realize the indoor multi-layer space path planning of the building in the three-dimensional space. The method has the advantages of simplicity and high execution efficiency, and effectively solves the problems that the indoor emergency route searching is difficult to visualize in real time, the indoor barrier entity is difficult to consider, and the route measuring and searching planning precision is difficult to ensure at present. The method is suitable for various BIM model data, especially large-scale BIM model data.

Drawings

FIG. 1 is a main flow chart of an indoor emergency path-finding method of a construction information model based on a subdivision grid according to the present invention;

fig. 2 is a detailed flowchart of an indoor emergency path finding method of a building information model based on a subdivision grid according to an embodiment of the present invention;

FIG. 3 is a flow chart of BIM model file conversion and loading provided by the embodiment of the present invention;

fig. 4 is a structural diagram of a GLTF file composition provided by an embodiment of the present invention;

fig. 5 is an analysis flowchart provided in the embodiment of the present invention.

Detailed Description

The invention is described in detail below by way of example with reference to the accompanying drawings.

The invention provides an indoor emergency road finding method of a building information model based on a subdivision grid, wherein the main line flow is shown as a figure 1, and the method comprises the following steps:

firstly, building information model BIM data of a building is taken for model analysis, and coordinate information and attribute information of each part in the building are obtained;

replacing each part in the building by adopting a subdivision grid matched with the scale to obtain a grid map of the building; carrying out passable judgment according to attribute information corresponding to the split grids, and setting passable marks for the split grids;

and thirdly, acquiring information of a starting point and an end point, wherein the starting point and the end point are both positioned on a grid map of the building, and acquiring an optimal path between the starting point and the end point by adopting an A-x routing algorithm.

The detailed flow of the embodiment of the present invention is shown in fig. 2.

For step one, the embodiment of the present invention provides an example as shown in fig. 3, and the specific steps are as follows:

s101, building information model BIM data of a building are taken and converted into a GLTF file; and converting and loading the format of the BIM model. The file type of the BIM model is FBX. The FBX file is difficult to parse and does not support loading, so the file is first type-converted and then loaded, the steps include S1011 to S1013:

s1011, the BIM data of the building information model of the building is an FBX file; converting the FBX file into an OBJ file; specifically, the FBX file may be converted into an OBJ file by 3D MAX software.

S1012, converting the OBJ file into a DAE file in an open source format; a plug-in OpenCOLLADA may be installed in the 3D MAX software and converted into a DAE file in an open source format.

S1013, converting the DAE file in the open source format into a GLTF file. The DAE file is converted into the GLTF file which is easy to analyze and load, an open source pipeline tool developed by a Khronos Group is needed, the DAE file can be directly converted into the GLTF file, and the tool can be directly downloaded on a GitHub. Entering a command mode under Windows, entering a file where COLLADA2GLTF-bin.exe is located, inputting the following command for conversion, and obtaining a GLTF file in a target folder by-f DAE model path-e.

After the GLTF file is successfully converted, the GLTF file can be loaded on the platform. The 3D model is loaded in two modes, one mode is that an entity is added and an entity method is called; the other is to call a speculative method by prototype addition. The results obtained in both ways are essentially the same.

The GLTF file is mainly composed of four parts as shown in fig. 4. The first part is a JSON file (. JSON), which mainly stores the contents of the model such as node hierarchy, material, camera, light, and the like. The second part is a binary file (. bin) used for storing the graphics data of the model, such as vertex coordinates, texture coordinates, indexes, animation and other data contents, which are mainly used for establishing a data buffer area for WebGL graphics rendering. The third part is some image files, such as pictures in PNG, JPG format, etc., used for texture mapping of the model. The fourth part is the shader file (. glsl), which is mainly the vertex shader and fragment shader needed for graphics rendering. And analyzing the GLTF file, namely analyzing the core file of the GLTF file, wherein the core of the GLTF file is the JSON file of the GLTF file.

As shown in fig. 5, S102 includes the following specific steps:

step 1021: parsing GLTF by using a primary function JSON.parser of JS, and converting a character string file in a JSON format into a JSON object;

step 1022: and respectively reading graphic information such as vertex coordinates, texture coordinates, normal lines, indexes and the like, scene information such as cameras, animations and the like, shader and texture picture information corresponding to the model and the like from the JSON object.

Step 1023: after obtaining the above information, the create reads the corresponding vertex coordinates, texture coordinates, indexes, and other specific data from the binary file (. bin), and creates the corresponding buffer area.

Step 1024: vertex shaders and fragment shaders are created, and various environment and material attributes are set using WebGL functions. And finally, transmitting the generated WebGL rendering information to a visualization module.

Coordinate information of various components of the building based on a Cartesian space rectangular coordinate system is obtained through model analysis, the coordinate information obtained through the model analysis is the offset of each component relative to the center point coordinate of the building information model, and the coordinates of the components need to be converted to a WGS84 geographical coordinate system. The method comprises the following specific steps:

step 1031: the coordinates of the center point of the model may be set, and in the WGS84 geographic coordinate system of the known coordinates of the center point in the embodiment of the present invention, longitude is long, latitude is lat and elevation is alt, and the coordinates of the center point are (long, lat, alt).

Step 1032: and (x, y, z) corresponding to the rectangular coordinate system of the Cartesian space is calculated by the component.

Step 1033: according to the analyzed coordinate data, the coordinates are offset relative to the coordinates of the central point and are assumed to be (X, Y, Z), so that (X + X, Y + Y, Z + Z) are corresponding positions of the component in the rectangular coordinate system in the Cartesian space.

Step 1034: all calculated (X + X, Y + Y, Z + Z) are converted into corresponding (lng, lat, alt) in the WGS84 geographic coordinate system to find the required target coordinates.

In the embodiment of the invention, a GeoSOT 3D mesh is adopted in the second step, the hierarchy of the GeoSOT 3D mesh is determined according to the size of the current component, and the GeoSOT 3D mesh of the determined hierarchy is used as the mesh matched with the corresponding scale of the current component; and (3) replacing all components in the building by adopting a subdivision grid matched with the scale of the components, thereby obtaining a grid map of the building.

And (3) designing the scale and level of the subdivision grid, selecting the subdivision grid level with the appropriate scale according to the size of the actual building model, and determining the size of a single grid. The single mesh size used was determined to be 0.5 meters, by half the size of most gates, and the hierarchy was known to be 27 levels with reference to the GeoSOT mesh hierarchy table.

And (3) designing storage data of a single grid unit, respectively carrying out gridding processing, grid packaging and the like on the information such as a wall, a staircase, a door, a window and the like of each part of the building, which is obtained by analysis, and finally generating an accurate grid map in the building information model. And taking the binary mode of [0, 1] as a mark for judging whether the grid passes or not. Wherein 0 is passable and 1 is impassable. And judging whether the traffic can pass according to the components in the grid, wherein the traffic is 1 if the traffic is a wall or other obstacles, and the traffic is 0 if the traffic is stairs, doors, windows and the like.

In the embodiment of the invention, the third step specifically comprises the following steps:

s1, establishing an expansion point list and a deletion point list, wherein the expansion point list is initially stored in a starting point, and the deletion point list is initially empty; taking the starting point as an initial value of the processing point; simplifying each subdivision grid in a grid map of a building into a point;

s2, taking all the adjacent points of the processing points, traversing the deletion point list, taking all the adjacent points which are in the deletion point list and are passable in the grid and do not exist in the deletion point list as undetermined extension points;

The indoor emergency path-finding method of the building information model based on the subdivision grids has the advantages of being concise and high in execution efficiency, and effectively solves the problems that the indoor emergency path-finding is difficult to visualize in real time, the indoor obstacle entity is difficult to consider, and the path-finding planning precision is difficult to guarantee at present. The method is suitable for various BIM model data, especially large-scale BIM model data.

In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An indoor emergency path-finding method of a building information model based on a subdivision grid is characterized by comprising the following steps:

taking BIM data of a building information model of a building to perform model analysis, and obtaining coordinate information and attribute information of each part in the building; the method specifically comprises the following steps:

s101, building information model BIM data of a building are taken and converted into a GLTF file;

s102, analyzing the GLTF file to obtain coordinate information and attribute information of each part in the building based on a Cartesian space rectangular coordinate system;

s103, converting coordinate information of each component based on a Cartesian space rectangular coordinate system into coordinate information of each component based on a national basic geographic coordinate system;

replacing each part in the building by adopting a subdivision grid matched with the scale to obtain a grid map of the building; determining the hierarchy of the GeoSOT 3D split grid according to the size of the current component by adopting the GeoSOT 3D split grid, and taking the GeoSOT 3D split grid of the determined hierarchy as the split grid matched with the corresponding scale of the current component;

replacing all components in the building by adopting a subdivision grid matched with the scale of the components, thereby obtaining a grid map of the building;

carrying out passable judgment according to attribute information corresponding to the split grids, and setting passable marks for the split grids; judging whether the traffic can pass according to the components in the grid, wherein the traffic is 1 if the traffic is a wall or other obstacles, and the traffic is 0 if the traffic is stairs, doors and windows;

acquiring information of a starting point and an end point, wherein the starting point and the end point are both positioned on a grid map of the building, and acquiring an optimal path between the starting point and the end point by adopting an A-path searching algorithm, and the method specifically comprises the following steps:

s1, establishing an expansion point list and a deletion point list, wherein the expansion point list is initially stored in the starting point, and the deletion point list is initially empty; taking the starting point as an initial value of the processing point; simplifying each subdivision grid in the grid map of the building into a point;

s3, calculating a cost function F (n) value by taking each undetermined expansion point as an intermediate point n, taking the undetermined expansion point with the minimum corresponding F (n) value as an expansion point, and storing the expansion point into an expansion point list;

the cost function f (n) is the sum of the actual cost from the starting point to the intermediate point n and the estimated cost from the intermediate point n to the end point; the actual cost from the starting point to the intermediate point n is the Euclidean distance from the starting point to the intermediate point n, the estimated cost value range from the intermediate point n to the terminal point is [ a, b ], a is the Euclidean distance from the intermediate point n to the terminal point, and b is the Manhattan distance from the intermediate point n to the terminal point;

s4, if the adjacent points of the extension points are not passable, storing the current extension points into a deletion point list, and returning to S2; otherwise, taking the extension point as a processing point, and returning to the step S2;

2. The method as claimed in claim 1, wherein the step of converting the building information model BIM data of the building into the GLTF file comprises the steps of:

s1011, the BIM data of the building information model of the building is an FBX file; converting the FBX file into an OBJ file;

s1012, converting the OBJ file into a DAE file in an open source format;

s1013, converting the DAE file in the open source format into a GLTF file.

3. The method according to claim 2, wherein the mesh map of the building is obtained by replacing each component in the building with a split mesh with a matched scale, specifically:

determining the hierarchy of the GeoSOT 3D split grid according to the size of the current component by adopting the GeoSOT 3D split grid, and taking the GeoSOT 3D split grid of the determined hierarchy as the split grid matched with the corresponding scale of the current component;