KR101465483B1 - Bim data processing system for comprising lod data - Google Patents

Abstract

The present invention relates to a BIM data processing system forming LOD data. The BIM data processing system according to one aspect of the present invention generates the LOD data in a 3D GIS platform to visualize the building information modeling (BIM) data of a building. The BIM data processing system according to the embodiment of the present invention includes a data receiving unit which receives the BIM data of the building, an envelope object extracting unit which extracts a building envelope object from the inputted BIM data, an LOD generating unit which generates LOD4 data using the extracted envelope object and generates the LOD data of the remaining step, and a storing unit which stores the generated LOD data of each step.

Description

TECHNICAL FIELD [0001] The present invention relates to a BIM data processing system for constructing LOD data,

The present invention relates to a BIM (Building Information Modeling), and more particularly, to an attribute input module and an input method of a BIM tool.

BIM (Building Information Modeling) refers to the process of modeling a facility in a multi-dimensional virtual space such as planning, design, engineering (structure, facility, electricity, etc.), construction, further maintenance and disposal. In particular, it enables the design and construction of low-cost buildings with cutting-edge design and environment-friendly energy, which is a recent issue, and is a similar concept to the multi-dimensional virtual design construction (VDC). In recent years, the application of BIM has been widely used in civil and plant fields in Europe and the US because it covers all construction environments as well as construction environments.

The building of the BIM (Building Information Modeling) means the entire life cycle of the target building - design, construction, operation and management, and the information means all information included in the entire life cycle of the target building , Modeling refers to an integrated tool and platform that produces, manages, and publishes all information contained in the entire life cycle.

BIM can digitize buildings to produce numerical data, and can display 3D display effects. Data of a length connecting the start point and the end point of the line is generated rather than a simple line and a surface operation, and the area is data based on the closed plane. By combining the data of length and area, volume data can be obtained.

BIM expresses each property of building objects such as walls, slabs, windows, doors, roofs, stairs, etc., and recognizes each other's relations and immediately reflects the building elements to the building design. Regardless of whether the building to be designed is regular or unstructured, the data generated when building the building is integrated and managed at all levels through compatibility and sharing of each project and each process.

A geographic information system (GIS) is a computer system that collects and makes available the hardware, software, and geographic data of a computer that is designed to collect, store, update, coordinate, analyze and represent all types of geographically referential information .

GIS is a system for storing, extracting, managing, and managing information by linking geographical information that represents a spatial location for various earth surface information references and non-graphic attribute information that explains and complements its form and function with graphical and database management functions. It is an information system related technology to analyze, and it is a comprehensive analysis means that expresses the spatial relation of map by adding characteristic (attribute) information of the geographical information. Geographic data occupying spatial position and related attribute data are integrated and processed. GIS can be widely used in land information management, facility management, transportation, urban planning and management, environment, weather forecasting, agriculture, disaster and disaster, education and population prediction.

From the point of view of the purpose of use, GIS can be divided into Facility Management (FM) system and decision support system for planning support, Land Information System (LIS) (UIS: urban information system).

Recently, an integrated data model that integrates BIM (IFC) data in the construction field and GIS data in the field of spatial information is required for combining and interoperating BIM and GIS, and such studies are underway.

As the demand of 3D building model worldwide increases and the utilization field using 3D building model becomes various, the importance of platform that can serve spatial information of urban model unit by using 3D building model and terrain information Has been highlighted. In addition, since the urban model is composed of numerous buildings, a quick and efficient visualization method of the three-dimensional model is becoming an important factor. Particularly, when screen display is performed on a large-capacity three-dimensional object using a device having limited performance such as a mobile device, smooth operation due to limitation of rendering performance is impossible. In order to solve such a problem, it is essential that a technique for reducing data through a detailed step (LOD) model construction for a three-dimensional real-world model is essential.

Levels of Detail (LOD) are the level of detail in modeling information, which is one of the things that must be negotiated when performing BIM. If the configuration of the LOD model is not clear, it can be confusing to model construction information among stakeholders.

The basic idea of the detail step (LOD) is to use a more compact representation if an object is small or does not contribute to the rendered image. For example, a detailed three-dimensional object model of approximately 10,000 triangles is used when the observer is close to the object. If an observer moves away from an object, simply using a simplified model of about 100 triangles can be seen to be nearly identical to the original model because of the distance. With this method, a considerable speed increase can be expected due to the light weight of the data.

In recent 6 to 7 years, studies on how to construct LOD data by automatically weighting 3D building model in GIS field have been actively studied. Particularly, studies related to LOD generation have been focused on soft polygonal mesh (topography) or regular prismatic three-dimensional building model. However, studies on automatic weight-reduction technology for three- , And further research and development are necessary.

With the advent of Google Earth, the three-dimensional GIS, which has become a global issue, takes the form of connecting individual objects such as terrain and buildings into a series of successive triangles. Each successive triangle is called a mesh, and a three-dimensional object based on the mesh is defined as a mesh model.

The fineness of the mesh model depends on the size of the individual triangles constituting the three-dimensional object. In order to describe a more detailed shape, the size of the triangle becomes smaller and the quantity becomes larger. However, since weight reduction and LOD construction are essential to realize quick and efficient visualization of a 3D building model in the form of a polygon mesh used in a GIS (for example, a 3D GIS platform), it is necessary to visualize a large number of large- In order to reduce the weight of the BIM data and configure the LOD, it is necessary.

Conventionally, lightweight and LOD construction are essential to realize quick and efficient visualization of a three-dimensional building model in the form of a polygon mesh used in a GIS (e.g., a three-dimensional GIS platform). Therefore, a large number of large- In order to make it visible, weight reduction of the BIM data and LOD configuration are indispensable.

In order to combine BIM and GIS in future and to develop various applications by interoperating with each other, efficient three-dimensional visualization is indispensably required. However, research on the weight reduction and LOD composition of BIM data has not been conducted yet, Efforts are needed to resolve concerns and challenges.

It is an object of the present invention to provide a method of constructing an LOD for BIM data that constitutes LOD data step by step according to the viewpoint of an observer in order to quickly and efficiently visualize large capacity BIM data on a 3D GIS platform.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the present invention will be realized and attained by the structure particularly pointed out in the claims, as well as the following description and the annexed drawings.

The present invention contemplates a method of constructing a step-by-step LOD (e.g., LOD1, LOD2, LOD3, LOD4) according to a view point of a 3D GIS platform, (Eg, buildings, bridges, urban facilities, etc.) can be visualized more quickly and efficiently.

LOD1, LOD2, LOD3, LOD4) which can reduce the amount of data and make it appear almost similar to the original model according to the observation time of the operator, It is possible to expect improvement.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a BIM data processing system interworking with a GIS according to the present invention; FIG.
2 is a flow diagram of a method for visualizing BIM data in a GIS platform in accordance with the present invention;
3 is an exemplary view showing a form of a three-dimensional mesh model;
4 is a view illustrating a lightening procedure of a polygon mesh type among building objects.
FIG. 5 is a diagram illustrating an example of a procedure for weight reduction and LOD data generation for a chair object. FIG.
6 is a flowchart illustrating a procedure for extracting a shell object of a building according to the present invention.
FIG. 7 is an exemplary view showing photographing points set around a building for 2D image acquisition. FIG.
8 is an exemplary view showing a pixel value inspection for extracting a skin object;
9 is a flowchart of a method for constructing LOD data of a building envelope object according to the present invention.
10A is an exemplary view showing a building envelope object in the LOD4 stage
FIG. 10B is an exemplary view showing a building envelope object in the LOD 3 stage; FIG.
FIG. 10C is an exemplary view showing a building envelope object in the LOD2 stage; FIG.
FIG. 10D is an exemplary view showing a building envelope object in the LOD1 stage; FIG.
11 is a flowchart related to a format conversion method of BIM data according to the present invention.
12 is an exemplary view showing an octree-based spatial indexing structure applied to the data format of the present invention;
13 is an exemplary view showing a configuration of a data format according to the present invention;
14A is a table showing the structure and components of a header according to the present invention.
14B is a table showing the structure and components of an object index according to the present invention.
14C is a table showing the structure and components of a spatial index according to the present invention.
FIG. 14D is a table showing the structure and components of geometric data according to the present invention; FIG.
FIG. 14E is a table showing the structure and the constituent elements of the attribute data according to the present invention; FIG.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1 is a block diagram of a BIM data processing system interworking with a GIS according to the present invention.

1, a BIM data processing system 100 according to the present invention includes a data receiving unit 10, a data selecting unit 20, a data converting unit 30, a controller 40, a shell object extracting unit 50, an LOD generation unit 60, and a storage unit 70.

The data receiving unit 10 may be configured to receive a BIM-based 3D object (e.g., a building, a bridge, a city facility, or the like) from a 3D GIS platform (e.g., Google Earth, V- (BIM data) of the objects (for example, buildings, bridges, urban facilities, etc.) from the user is input to the user to be represented on the world wind.

When the input of the IFC data (BIM data) is completed, the data selector 20 divides the data storage format of the objects constituting the geometry information of the IFC data into a parametric form or a polygon mesh form, The data of the polygon mesh type is selected.

The data converter 30 converts the parametric data among the input BIM data into a polygon mesh. Also, the geometry information of the input BIM data is converted into a polygon mesh form, and the attribute information of the BIM data is grouped in units of objects.

The LOD generation unit 60 includes a first LOD generation unit 64 and a second LOD generation unit 68. The LOD generation unit 60 reduces the input BIM data and generates predetermined LOD data.

The first LOD generator 64 constructs (generates) the LOD data related to the polygon mesh data selected in step S200 or S300 and converted into the mesh model (for example, an in-building accessory). The second LOD generation unit 68 constructs (generates) LOD data (for example, LOD1 to LOD4) for each stage of the building exterior object extracted by the exterior object extraction unit 50.

The control unit 40 controls the operation of the respective components (e.g., the data receiving unit 10, the data selector 20, the data converting unit 30, the shell object extracting unit 50, the LOD generating unit 60, 70) to control the operation of the system 100. [ The control unit 40 divides the objects to be visualized on an octree basis and assigns an index thereto. The control unit 40 stores the index information and the result data of the data conversion unit 30 and the LOD generation unit 60 in a header, an object index, a spatial index, , Geometry data, and property data in a data format consisting of five components.

The shell object extraction unit 50 extracts a building shell object from the input BIM data. The enclosure object extracting unit 50 refers to the BIM data, calculates a bounding box, sets a plurality of points outside the bounding box as photographing points, and displays the images (taken) And extracts the skin object by inspecting each pixel of the extracted 2D image in order.

The storage unit 70 stores the LOD data generated by the first LOD generator 64 and the second LOD generator 68. In addition, the extracted building envelope object is stored, and when the BIM data is converted into a format applicable to the 3D GIS platform, the converted data and the structure of the format are stored.

Figure 2 is a flow diagram of a method for visualizing BIM data in a GIS platform in accordance with the present invention.

2, the BIM data visualization method on the GIS platform according to the present invention includes a process of receiving BIM data of a corresponding object (e.g., a building, a bridge, a city facility, etc.) (S100) (S300) of transforming the parametric data of the input data into a polygonal mesh shape (S300), and a process of selecting and converting (S200, S300) the data of the polygon mesh (S500) of extracting a building envelope object from the inputted BIM data (S500), and constructing LOD data of the extracted building envelope object (S600 , And storing the LOD data (S700).

Each step of the method of visualizing the BIM data will be described in more detail as follows.

In order to allow a BIM-based three-dimensional object (e.g., a building, a bridge, an urban facility, etc.) to be represented on a three-dimensional GIS platform, the system 100 (data receiving unit 10) (BIM data) of a building (eg, a building, a bridge, an urban facility, etc.). (S100)

When the input of the IFC data (BIM data) is completed, it is determined whether the data storage format of the objects constituting the geometry information of the IFC data is a parametric shape or a polygon mesh shape, do. (S200) Then, the parametric data is converted into polygon mesh data. (S300)

In the present invention, it is necessary to convert the parametric data, that is, parametric based objects, into polygon mesh type data for display (visualization) on the screen, And the LOD data configuration.

The objects of the building in which the geometry information of the IFC data is stored in the form of a polygon mesh are composed of a myriad of vertices as shown in FIG. 3 as an appendage of a building having a complex shape such as a desk or a chair . Each triangular shape shown in FIG. 3 is referred to as a mesh, and a three-dimensional object constructed based on the mesh is referred to as a mesh model. 3 is an exemplary view showing a form of a three-dimensional mesh model.

As shown in FIG. 3, the mesh model describes only the shape information of the surface of the three-dimensional object, and the interior of the mesh model represents an unfilled shape. The detail of the mesh model depends on the size of the individual triangles constituting the three-dimensional object. In order to describe a more detailed shape, the size of the triangle becomes smaller and the quantity becomes larger.

Generally, mesh-based three-dimensional GIS data has different types of detailed storage formats. However, there are basically three kinds of vertex list, face list, and UV list Item, and is usually stored in binary form.

The vertex list stores sequentially the three-dimensional coordinates of all the points constituting the three-dimensional object along with the point ID.

The face list defines an individual triangular plane composed of three vertices and is composed of only a point ID included in a vertex list.

The UV list specifies a position of a texture in a texture image to be applied to each face. The UV list includes a point ID of a vertex constituting a face, And 1: 1, respectively. If you apply a separate file type texture to each face, you do not have to save the UV list separately, but you can specify the file name directly, Use a single texture file.

Unlike mesh-based GIS data, IFC data represented by the standard format of BIM is parameter-based. In other words, in order to represent a rectangular parallelepiped such as a wall, GIS data directly stores three-dimensional coordinates of all the edges constituting the rectangular parallelepiped and the triangular plane thereof, whereas the BIM data indicates that three end points of the center line (Geometry information), the thickness of this line, and the height of the wall surface (attribute information). Therefore, unlike GIS data, BIM data is characterized in that it is required to calculate its shape every time based on the stored parameters in order to display the three-dimensional shape of the object on the screen.

In order to visualize the parametric based object (BIM data) on the screen, it is necessary to convert the data into polygon mesh type data, which is used to lighten the building envelope object and to construct the LOD data.

Upon completion of the above-described conversion process (S300), the system 100 (LOD generation unit 60) selects LOD data of the polygon mesh data selected in step S200 and transformed in step S300. (S400)

As described above, among the objects constituting the building, the objects stored in the form of the polygon mesh are composed of numerous vertices as an appendage of buildings having complex shapes such as desks and chairs. A method of lightening the object model and constructing the LOD data is as shown in FIG. 4 is a view illustrating a lightening procedure of a polygon mesh type among building objects.

For example, when a predetermined light weighting algorithm is applied to a chair (an object in the form of a polygon mesh) as one of adjuncts of a building, step-by-step LOD data is constructed as shown in FIG. 5, Can be improved. FIG. 5 is a diagram illustrating an example of a weighting and LOD data generation procedure for a chair object.

5, when the object lightening and the LOD data construction (S400) are all completed, the system 100 (enclosure object extraction unit 50) extracts the building exterior object from the input BIM data . (S500)

When the spatial range of visualizing the BIM data on the 3D GIS platform is an urban unit, visualization is performed on a plurality of three-dimensional objects (e.g., buildings, bridges, urban facilities, etc.) By constructing (creating) LOD data for the exterior object of the building, it improves the three-dimensional visualization performance of the large-capacity BIM data.

The system 100 of the present invention automatically extracts the building envelope object and constructs the LOD data for each step (e.g., LOD1 to LOD4).

6 is a flowchart illustrating a procedure for extracting an enclosure object of a building according to the present invention.

As shown in FIG. 6, the system 100 (e.g., the shell object extraction unit 50) first calculates a bounding box by referring to the BIM data input through the process S100. (S510). The bounding box means a rectangular parallelepiped having the minimum size surrounding the building. The enclosure object extracting unit 50 compares the vertex coordinates of the geometry information of the object constituting the building, Calculate the bounding box.

Then, a plurality of points outside the bounding box are set as photographing points so that the entire outer shape of the object (e.g., building) can be extracted. (S520) The process of setting a photographing point (S520) sets the position and direction of the camera for acquiring a 2D image, such as photographing a photograph of the three-dimensional building, as shown in FIG. 7 . At this time, there are two conditions for setting the position and direction of the camera, and the entire building is included in the 2D image in which the building is to be expressed. First, the camera ray must pass through the center of the bounding box. Second, the bounding box should be included in the view frustum area, that is, the part where the camera is visible. FIG. 7 is an exemplary view showing photographing points set around a building for 2D image acquisition. The number of shooting points may vary depending on the complexity of the object (e.g., building) appearance.

Once the shooting points as shown in Fig. 7 are set, the images taken at each shooting point (which can be photographed) are extracted. (S530)

Before extracting a 2D image, all objects in the building are given unique color values according to the combination of RGB colors, and a total of 16,777,216 color combinations of RGB colors can be processed for all objects. The enclosure object extracting unit 50 extracts a 2D image of the building at each preset camera position (e.g., photographing point).

Then, each pixel of the extracted 2D image is checked in turn, and it is determined whether the pixel corresponds to the building envelope according to the color value of the pixel, as shown in FIG. (S540 to S550) FIG. 8 is a diagram illustrating an example of pixel value inspection for extracting a skin object.

If the color value of the pixel is white, the enclosure object extracting unit 50 determines the pixel as a margin (background) around the building, not the exterior object of the building, and if the pixel has a specific color value, It is judged that the object is a building envelope object. In this way, the skin object extracting unit 50 extracts all skin objects for the building by examining the pixel values of the images photographed at all camera positions, and stores the extracted data (skin object). (S560)

After the extraction process S500 of the building envelope object is completed, the system 100 (second LOD generation unit 68) constructs the LOD data of the extracted building envelope object according to the procedure shown in Fig. (S600) FIG. 9 is a flowchart of a method for constructing LOD data of a building envelope object according to the present invention.

Levels of Detail (LOD) are the level of detail in modeling information, which is one of the things that must be negotiated when performing BIM. If the configuration of the LOD model is not clear, it can be confusing to model construction information among stakeholders.

The system 100 according to the present invention uses a wall (ifcwall) object, a floor (ifcslab) object, and spatial structure information among object types of IFC data to form a footprint (LOD1 to LOD3) for the building envelope object are generated by extracting the footprint of the building exterior, detecting the outline of each floor using the extracted footprint. As shown in FIG. 9, the system 100 (second LOD generation unit 68) separates an inner object and an outer object of the building and generates LOD4 data using the separated outer object. (S610) FIG. 10A is an exemplary view showing a building envelope object in the LOD4 stage. LOD 4 is the level of LOD data that expresses the building envelope object in the most detailed detail, and has the capacity (for example, 8600 Kb) as the separated external object.

The second LOD generation unit 68 also extracts a footprint for each floor of the building using an ifcwall object, an ifcslab object, and spatial structure information. (S620)

Then, the outline of each floor is created using the extracted footprint. (S630) The second LOD generation unit 68 generates a profile for each floor by extracting a polyline expressing the outermost building from the floor footprint.

Then, the generated outline (profile) of each layer is extruded by the layer height, and the extracted model of each layer is combined to generate LOD3 data. (S640 to S650) FIG. 10B is an exemplary view showing a building envelope object in the LOD3 stage. The LOD3 is a level data representing the building exterior object in detail after the LOD4 data, and has a capacity (for example, 158 Kb) that is lighter than the LOD4 data.

If LOD2 data is to be generated, the second LOD generator 68 extrudes the outline of the lowest floor of the building out of the floor outlines generated in step S630 by the height of the building. (S660) The LOD2 data can be generated by extruding the outline of the building floor at the height of the building. 10C is an exemplary view showing a building envelope object in the LOD2 stage. LOD2 has a capacity (for example, 32 Kb) that is lighter than the LOD3 data.

If the LOD1 data is to be generated, the second LOD generator 68 simplifies the outline of the lowest floor of the buildings among the outlines of the floor created in the step S630, and reduces the outline of the simplified building to the building height And extrudes the data to generate LOD1 data. (S670 to S680) The LOD1 data can be generated by extruding the outline of the simplest building to the building height. 10D is an exemplary view showing a building envelope object in the LOD1 stage. The LOD1 has a capacity (e.g., 2 Kb) that is lighter than the LOD2 data.

The LOD1 building envelope object simplifies the edges of the profile of the lowest layer of the building with unevenness and extrudes the simplified profile to the height of the building, And creates a shout object.

1, the system 100, the control unit 40) transmits the LOD data configured in the respective procedures S400 and S600 to the storage unit 70 (step S600) ). (S700)

11 is a flowchart of a format conversion method of BIM data according to the present invention.

Due to the different characteristics and different characteristics of the BIM (IFC) data in the construction field and the GIS data in the spatial information field, when the BIM data is visualized on the GIS data (eg 3D GIS platform), the geometry elements and properties ) Additional definition of the element, verification of the sample data, and so on. 11 is a diagram illustrating a procedure for converting the format of the BIM data in order to visualize the BIM data in the 3D GIS platform.

In fact, the existing IFC format is a standard format for compatibility with BIM data built by different BIM modeling software (eg Revit, ArchiCAD, etc.) and is not a format developed for visualization purposes. Therefore, the service format to be implemented in the present invention has two purposes of visualizing IFC data in the GIS platform and quickly visualizing large-capacity IFC data.

Since the service format according to the present invention includes almost all the information of the IFC data even in the conversion format, it is possible to extract all the information of the IFC data, and furthermore, the additional information (LOD data, Spatial indexing information).

As shown in FIG. 11, the method for converting BIM data according to the present invention comprises the steps of converting the input BIM data into a polygon mesh and grouping the input BIM data on a per object basis (S810) A step S830 of dividing the object to be visualized on the basis of the octree and adding an index to the object to be displayed on the basis of the header of the object, (S840) of storing the information in each element of the data format, such that the element is composed of five components such as a spatial index, geometry data, and property data.

When the BIM data is input through the input procedure S100, the data conversion unit 30 converts the input BIM data into a polygon mesh form and groups the objects in units of objects. (S810)

The data conversion unit 30 first converts the geometry information of the input BIM data into a polygon mesh shape.

Unlike mesh based GIS data, geometry information of BIM data represented by IFC standard format is parameter based. In other words, in order to represent a rectangular parallelepiped such as a wall, GIS data directly stores three-dimensional coordinates of all the edges constituting the rectangular parallelepiped and the triangular plane thereof, whereas the BIM data indicates that three end points of the center line Dimensional coordinates, the thickness of this line, and the height of the wall. Accordingly, through the conversion process (S810), the data conversion unit 30 converts the parameter-based geometry information into geometry information in the form of a polygon mesh, and stores the geometry information in the internal data structure of the storage unit 70. [

The data conversion unit 30 further groups the property information of the input BIM data in units of objects.

The property information according to the IFC format definition is distributed and stored. The attribute information related to the object and other attribute information related to the attribute information are linked according to the relationship rules. Accordingly, through the conversion process (S810), the data conversion unit 30 groups the attribute information of the input BIM data in units of objects and stores it in the internal data structure of the storage unit 70. [

Meanwhile, the system 100 performs a procedure of weighting the BIM data and constructing the LOD data according to the procedure S600 shown in FIG. (S820) The data format according to this example is developed for the purpose of quick visualization of a large-capacity BIM (IFC format) data. The system 100 performs weighting on each object to generate LOD data, and generates LOD data by using five components (e.g., a header, an object index, a spatial index, a geometry data , And Property data) in accordance with the present data format.

The system (100, control unit (40)) also divides objects to be visualized on an octree basis and assigns indexes as shown in FIG. (S830) FIG. 12 is an exemplary view illustrating an octree-based spatial indexing structure applied to the data format of the present invention.

Since the BIM (IFC) data is a large amount of data and is composed of many objects, the building data is divided into an octree-based space as shown in FIG. 12, indexes are indexed to objects included in each space, . When visualizing BIM (IFC) data through such a data structure, only the objects included in the visible space on the screen can be quickly searched and visualized.

13 is a diagram showing an example of a configuration of a data format according to the present invention.

As shown in FIG. 13, the data format according to the present invention includes a header, an object index, a spatial index, geometry data, and property data, The header information includes information on a link model file and general information on one building object. The object index and the spatial index information are information on a building or an object in the building (Index) information for searching for the indexes. The geometry data and property data store all the geometry and property information of the building object included in the BIM (IFC) data.

When the steps S810, S820, and S830 are completed, the system 100 and the control unit 40 determine whether the five components (e.g., a header, an object index, a spatial index Spatial (S810, S820, and S830) in accordance with the data format of the present example, which is composed of data, index, geometry data, and property data. (S840)

14A is a table showing the structure and components of a header according to the present invention.

A header according to the present invention stores general information including a signature, a version, and a file name of a linked model (BIM (IFC) data) as shown in FIG. 14A. (BIM (IFC) data) including the number of three-dimensional objects, the number of polygons, and the number of vertices included in the linkage model (BIM (IFC) data) Rotation, and scale factor to be mapped to the object.

14B is a table showing the structure and components of the object index according to the present invention.

The object index according to the present invention is composed of index information for quickly searching for geometry elements and property elements according to the degree of detail of each object as shown in FIG. 14B. The object index includes the center position of each object, the geometry element of the LOD-specific object in the file, the location where the property element is stored, and the length of the stored information. The object index structures and stores the resultant data in step S820.

14C is a table showing the structure and components of a spatial index according to the present invention.

The Spatial Index according to the present invention is composed of information for quickly searching and visualizing an object existing at a specific location in a space. Spatial Index is a spatial data structure used to efficiently represent a three-dimensional building object. The system 100 (control unit 40) uses an octree to refer to an object existing at the specific location as a 3 Split into dimensions. As shown in FIG. 14C, each element of the spatial index includes each node information divided into eight cubes for one space and index information of the object corresponding to each node. The Spatial Index structure and stores the result data of the process (S830).

FIG. 14D is a table showing the structure and components of the geometric data according to the present invention.

Geometry data according to the present invention stores geometry information of each element object constituting an object (e.g., building) as shown in FIG. 14D. The geometry information includes a unique ID value used for distinguishing each object and geometry information for each LOD of the object. The geometry data of FIG. 14D structurizes and stores the resultant data of the process (S810).

FIG. 14E is a table showing the structure and constituent elements of the attribute data according to the present invention.

The property data according to the present invention stores property information of each element object constituting an object (e.g., building) as shown in FIG. 14E. The property information includes a unique ID value used for distinguishing each object and attribute information of the object. The property data of FIG. 14E stores the result data of the process (S810) in a structured manner.

The BIM data processing system 100 according to the present invention is preferably implemented in a 3D GIS platform in the form of an ADD-ON program.

As described above, the BIM data processing system 100 according to the present invention can be implemented as a computer-readable code on a medium on which a program is recorded. The computer-readable medium includes all kinds of recording devices in which data that can be read by a computer system is stored.

Examples of the computer-readable medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device and the like, and also implemented in the form of a carrier wave (for example, transmission over the Internet) . The computer may include a BIM data processing system 100.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. May be constructed by selectively or in combination. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

As described above, the present invention contemplates a method of constructing a stepwise LOD (e.g., LOD1, LOD2, LOD3, LOD4) according to a view point of a 3D GIS platform, (Eg, buildings, bridges, urban facilities, etc.) that are used in the BIM-based platform can be visualized more quickly and efficiently. In addition, by suggesting a method of constructing a stepwise LOD (eg LOD1, LOD2, LOD3, LOD4) that can lighten the amount of data and make it appear almost similar to the original model according to the observation time of the operator, .

Claims (9)

1. A BIM data processing system for generating LOD data in a three-dimensional GIS platform for visualizing building information modeling (BIM) data of a building,
A data receiving unit 10 for receiving BIM data of the building;
An enclosure object extracting unit 50 for extracting a building exterior object from the input BIM data;
LOD4 data is generated by using the extracted skin object and a footprint is extracted from each layer by using an ifcwall object, an ifcslab object, and spatial structure information, An LOD generating unit 68 for generating outline lines for each floor using a footprint and extruding or simplifying the generated outlines for each floor to generate LOD data of the remaining steps;
And a storage unit (70) for storing the generated stepwise LOD data. The apparatus of claim 1, wherein the LOD generator (68)
Extruding the generated outline by layer height, and combining the extracted layered models to generate LOD3 data. The apparatus of claim 1, wherein the LOD generator (68)
Wherein the LOD2 data is generated by extruding the outline of the lowest floor of the building outline by the height of the building. The apparatus of claim 1, wherein the LOD generator (68)
Wherein the LOD1 data is generated by simplifying the outline of the lowest floor of the generated outline of each floor and extruding the outline of the simplified building with the height of the building. A method for generating LOD data in a three-dimensional GIS platform for visualizing Building Information Modeling (BIM) data of a building,
Generating LOD4 data using a separated external object by separating an inner object and an outer object of the building;
Extracting a footprint for each floor using an ifcwall object, an ifcslab object, and spatial structure information;
Generating an outline for each floor using the extracted footprint;
And generating LOD data of the remaining steps by extruding or simplifying the generated outline of each layer. 6. The method of claim 5, wherein the generating of the LOD data of the remaining steps comprises:
Extruding the generated outline of each layer by a layer thickness;
And generating LOD3 data by combining the extracted models for each layer. 6. The method of claim 5, wherein the generating of the LOD data of the remaining steps comprises:
And generating LOD2 data by extruding the outline of the building bottom layer out of the generated outlines of each layer by a building height. 6. The method of claim 5, wherein the generating of the LOD data of the remaining steps comprises:
Simplifying the outline of the lowest floor of the building among the generated outlines;
And generating LOD1 data by extruding the simplified outline of the building lower layer by a height of the building. A BIM data processing system for generating LOD data by receiving building information based on BIM (Building Information Modeling) in a 3D GIS platform,
A data selector 20 for selecting polygon mesh type data from the input BIM data;
A data converting unit (30) for converting parametric data among the input BIM data into a polygon mesh form;
A first LOD generator 64 for constructing LOD data on the selected and converted polygon mesh data, that is, in-building accessories;
An enclosure object extracting unit 50 for extracting a building exterior object from the input BIM data;
LOD4 data is generated by using the extracted skin object and a footprint is extracted from each layer by using an ifcwall object, an ifcslab object, and spatial structure information, A second LOD generation unit 68 for generating outline lines for each floor using a footprint, extruding or simplifying the generated outlines for each floor, and constructing LOD data of the remaining steps;
And a storage unit (70) for storing the LOD data configured as described above.

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