BIM information digital processing method and system based on IFC-GRID standard

Abstract

The invention relates to a BIM information digital processing method and system based on an IFC-GRID standard. The method comprises the steps that BIM data to be processed and stored according to the IFC standard are acquired; geometric model data in the BIM data are converted into forms of boundary representation entities, sweeping entities, construction entities and surface models for shape expression; converting display data in the BIM data into coloring display and texture mapping display; attribute data in the BIM data is subjected to extension customization, including object extension and object attribute extension, the object extension adopts an IFC standard language for re-description, and the object attribute extension adopts a mode of defining a new attribute set and an attribute type to describe entity characteristics. Compared with the prior art, the method has the advantages that the data conversion efficiency of the IFC-GRID standard is improved, the function is stable and reliable, and the IFC-based unified data expression mode IFC-GRID standard can be built.

Description

Technical Field

[0001] The present invention relates to the technical field of BIM data processing, and in particular to a BIM information digital processing method and system based on the IFC-GRID standard. Background Art

[0002] At present, the digitalization of power grid infrastructure projects mainly revolves around BIM (Building Information Modeling) technology and related technologies, and mainly conducts visualization and decision-making analysis research in engineering design, construction, management, etc. BIM technology has gradually become a common digital technology in the field of power grid engineering.

[0003] However, since BIM technology is mainly developed for the field of construction engineering, its native technology for the digitization of power grid engineering is almost blank, and there are many difficulties to be overcome in the localization of key BIM technologies for power grid engineering. Without a unified data interaction standard, it is impossible to expand the BIM model and corresponding model data encoding in the field of electrical engineering. Professional localized BIM software for power grid engineering is in urgent need of development, and the localization of BIM technology needs to be promoted. In existing research, in order to make the IFC standard applicable to areas that are not covered by the official standard, such as railway transportation and bridge components, researchers often study the expression system and operation mechanism of the IFC standard and expand the corresponding IFC standard entities through application needs to perform IFC expression.

[0004] In the process of applying BIM technology, data interaction of power grid projects is inevitable. In view of the lack of interaction standards, it is necessary to study relevant international standards, expand the IFC standard common entity in the field of power grid projects, and form an IFC-GRID standard based on power grid projects to provide a data base for BIM-based digital power design, thereby developing domestic key BIM technologies for power grid projects and forming a domestic digital design system. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a BIM information digital processing method and system based on the IFC-GRID standard, improve the data conversion efficiency of the IFC-GRID standard, and have stable and reliable functions.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for digital processing of BIM information based on the IFC-GRID standard, wherein the IFC-GRID standard is to extend the data structure based on the IFC standard and to connect with the types in the external classification system, and the method comprises the following steps:

[0008] Obtain BIM data stored in IFC standard to be processed;

[0009] The geometric model data in the BIM data is converted into shape expression in the form of boundary representation entities, swept entities, construction entities and surface models. The boundary representation entity uses boundary surface constraints to represent three-dimensional objects; the swept entity uses an implicit modeling method to stretch and rotate a two-dimensional section to create a three-dimensional entity; the construction entity represents a three-dimensional object by performing Boolean operations on objects or primitives;

[0010] The display data in the BIM data is converted into a shaded display and a material mapping display, wherein the conversion process of the shaded display is to convert the color component data in the display data into normalized floating point numbers; the conversion process of the material mapping display is to convert the display data into storage in the form of picture links, binary streams or pixels;

[0011] The attribute data in the BIM data is expanded and customized, including object expansion and object attribute expansion. The object expansion is re-described in the IFC standard language, and the object attribute expansion describes the entity characteristics by defining new attribute sets and attribute types.

[0012] Furthermore, during the geometric model data conversion process, the BIM data is also classified to distinguish whether it is a conventional model or a complex model. If it is a conventional model, the geometric model is described using boundary representation entities and swept entities; if it is a complex model, it is described using a surface model.

[0013] Furthermore, during the shading display process, the material with the texture is displayed with the material base color as the unified rendering color of the model surface.

[0014] Furthermore, the image link in the conversion process of the material map display is a local path or a network path; the binary stream is stored in text represented by hexadecimal; and the pixel method stores the color value of each pixel in text form.

[0015] Furthermore, the display data conversion process also includes expressing the internal structure in a dotted line style through a line blanking algorithm.

[0016] Furthermore, the attribute data extension customization process specifically describes the extension category and customized entity Schema information in Express mode. When the export action is executed, the IFC extension objects and attributes of the power grid engineering category are obtained by performing IFC-GRID standard parsing.

[0017] Furthermore, the object attribute extension extracts and converts the attributes in the internal data structure based on the attributes of the object, and converts the attributes into IFC attribute sets and attribute types.

[0018] Furthermore, the attributes in the internal data structure include material, cost and performance parameters.

[0019] Furthermore, the conversion of the attribute includes unit conversion.

[0020] Furthermore, the method further includes: determining whether the volume of the model file obtained after the BIM data processing is greater than a preset volume threshold, and if so, performing multiplexing and compression processing on the geometric model data and the attribute data.

[0021] The present invention also provides a BIM information digital processing system based on the IFC-GRID standard, comprising a memory and a processor, wherein the memory stores a computer program, and the processor calls the computer program to execute the steps of the method described above.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) In order to implement the setting of the IFC-GRID standard, the present invention provides a conversion and analysis solution for the IFC-GRID standard data. Through the geometric capability, display capability, and component data encapsulation capability, the geometric information, attribute information, style information, relationship information, etc. in the BIM model can be matched with the mapping rules set by the IFC-GRID standard, thereby improving the data conversion efficiency of the IFC-GRID standard and having stable and reliable functions.

[0024] (2) The present invention integrates the IFC-GRID standard into basic applications and design applications, reduces the designer's secondary information matching of the model, efficiently produces design models that meet the delivery standards through customized applications, and realizes the data conversion of IFC-GRID standard model results through the mapping rules provided by the IFC Schema file. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention provides a flowchart of a BIM information digital processing method based on the IFC-GRID standard in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0029] Example 1

[0030] like Figure 1 As shown, this embodiment provides a BIM information digital processing method based on the IFC-GRID standard. The IFC-GRID standard is to expand the data structure based on the IFC standard and to connect with the types in the external classification system. The method includes the following steps:

[0031] S1: Acquire BIM data to be processed and stored in the IFC standard;

[0032] S2: Convert the geometric model data in the BIM data into shape expressions in the form of boundary representation entities, swept entities, construction entities and surface models. Boundary representation entities use boundary surface constraints to represent three-dimensional objects; swept entities use implicit modeling methods to stretch and rotate two-dimensional sections to create three-dimensional entities; construction entities represent three-dimensional objects by performing Boolean operations on objects or primitives;

[0033] S3: converting the display data in the BIM data into shaded display and material mapping display. The conversion process of shaded display is to convert the color component data in the display data into normalized floating point numbers; the conversion process of material mapping display is to convert the display data into storage in the form of picture links, binary streams or pixels;

[0034] S4: Expand and customize the attribute data in BIM data, including object extension and object attribute extension. Object extension is re-described using the IFC standard language, and object attribute extension describes entity characteristics by defining new attribute sets and attribute types.

[0035] The following is a detailed description:

[0036] 1. BIM standards define the role and status of each standard in data sharing and integration of general engineering projects. For example, IFC is the data foundation for realizing BIM full life cycle management, IDM is a compilation manual for converting abstract information required by various disciplines into BIM standard data language, and MVD is a sub-model generated by different disciplines for specific application purposes such as structural calculation, construction simulation, cost estimation, etc. In order to ensure that the geometric accuracy and information depth of the power grid engineering information model delivered by all parties involved in engineering design during the entire life cycle of the substation are scientific and reasonable, meet actual engineering needs, and adapt to international general information standards to achieve open sharing, the domestic BIM technical standard system for power grid engineering is planned to consist of four parts, namely, data format standards, data exchange standards, model classification and coding standards, and data delivery standards. The four standards are based on the IFC standard, MVD standard, IFD standard, and IDM standard in the international general information standard system, and constitute the standardized data support of IFC-GRID (GIM Grid Information Model, power grid information model), providing a basic guarantee for the professional knowledge extraction and project data mining of power grid engineering.

[0037] (1) IFC Standard

[0038] IFC (Industry Foundation Classes) is the core data standard of BIM (ISO10303-21). It is a universal BIM data organization framework. Its purpose is to become a link for information sharing and transmission between different fields of large-scale projects such as civil engineering and electrical engineering, especially between different application software. Most current BIM software supports the reading and transcription of IFC data files. The IFC standard itself is an object-oriented modeling standard, which is an extension of EXPRESS in the application of civil engineering informationization. It contains a large number of definitions of product entities, process entities, geometric resources, role resources, etc. related to civil engineering, electrical engineering, etc.

[0039] The IFC standard is an object-oriented information model data standard formed by the EXPRESS description language. It contains four conceptual levels, namely the domain layer, the interaction layer, the core layer, and the resource layer. In order to reduce unnecessary development complexity, the reference method adopts the gravity mode, that is, the upper-level concepts can reference the lower-level concepts, but not vice versa. This can also ensure the stability of the entire information resource and improve the scalability of the data standard. Each layer contains different types of data types and entity definitions as the basic elements of the model description.

[0040] The latest IFC standard version is IFC4.3. Starting from the major version update from IFC2x3 to IFC4, IFC's official organization buildingSMART has gradually shifted its focus from buildings to the full life cycle management of urban assets, and gradually incorporated various urban infrastructures, such as the railway field, bridge field, port field, road field, and some common concepts and geometric expressions of urban infrastructure projects, paving the way for other possible infrastructure expansions, which provides a favorable foundation for the expansion of power grid projects. Starting from IFC4, the IFC standard has gradually expanded its description of urban infrastructure, which has included infrastructure engineering content in the fields of railways, highways, ports, waterways, etc. It not only improves the professional structure of the professional products and product types of the above-mentioned infrastructure, but also adds the spatial structure decomposition definition of the profession involved and the geometric expression of complex entities. Therefore, under the guidance of the experience of previous IFC standard version iterations, this project will form an extension of the IFC standard in the field of power grid engineering, namely the IFC-GRID standard, to meet the information needs of power grid engineering projects in terms of compatibility, openness, high-precision modeling, and standardization.

[0041] (2) MVD criteria

[0042] MVD (Model View Definition) is the exchange specification of BIM data, and is usually regarded as a subset of data exchange for specific purposes between different disciplines under the overall IFC framework. The complete IFC framework (IFCschema) is often too bloated for a specific engineering application scenario. In the widely used version, IFC2x3_TC1 contains 653 entities, while the latest IFC4x3_RC4 has been expanded to 876 entities, and as time goes by, the IFC standard will include more entity information. Therefore, in the actual data exchange application of different professional software in the project, all entities are often not transmitted. Instead, the original model is divided into multiple MVDs for shared transmission according to the needs of different professions, which can effectively improve the efficiency of information sharing.

[0043] MVD is a model subset that determines the information required for each stage of the process in the IFC model data under the guidance of IDM, which is used for model transmission between software. The complete IDM standard mainly consists of five parts: process map, exchange requirement, functional component, business rules and verification test. The core is the process map and exchange requirement. For the specified work requirements, the process map defines the participating roles and information exchange nodes. The exchange requirement explains the specific information exchange details of the process map, so that BIM users can exchange information and give detailed text descriptions. Functional components are IDM data information units, and a single exchange requirement is composed of several functional components. Business rules provide multiple constraints for a process. The verification test verifies whether each exchange requirement is accurate and met.

[0044] The development of MVD for power grid engineering can follow the following process: List-up stage, PM (Process Map) stage, ER (Exchange Requirement) stage, MVD stage, and SI (Software Implementation) stage.

[0045] The final power grid engineering information model view definition development results should include three parts: 1) Overall description of the power grid engineering information model view MVD. In order to enable the power grid engineering information model to be applied to the corresponding scenario and form the corresponding model, it is necessary to accurately define the data format of the power grid engineering information exchange based on IFC-GRID. This project intends to use the form of IFC-GRID binding for description, and draw the Diagram composed of each Concept in IFC-GRID to fully express the various types of information required for power grid engineering information communication, such as components, attributes, etc. 2) MVD-IFC-GRID binding diagram (Diagram). Draw the MVD-IFC-GRID binding diagram (Diagram) to describe the Diagram of the power grid engineering information model entity. Each variable Concept in the Diagram corresponds to the corresponding IFC-GRID entity object. At the same time, combine their levels to make the relationship between the concepts clearer. 3) MVD-IFC-GRID binding document description. Formulate a corresponding description document for each Concept in the power grid engineering MVD, and declare the attribute value symbol description of each entity (Entity) in the description document.

[0046] (3) IFD standard

[0047] The full name of the IFD standard is International Framework for Dictionaries. Its purpose is to define a scientific method for summarizing, defining, identifying and sorting out engineering concepts. The IFD standard requires the attributes or characteristics of information content, distinguishes and classifies information according to certain principles and methods, and establishes a certain classification system or arrangement method. The existing IFD standard refers to the encoding of the existing entity categories of IFC, but there is a lack of encoding for various components and equipment types involved in power grid projects, so corresponding expansion is needed.

[0048] According to the actual situation and design habits of the power grid project and the "Power Grid Project Digital Delivery Standard", IFD coding information is added to the power grid project BIM model based on the following principles:

[0049] First, the naming of projects, systems, and BIM components should comply with certain naming principles, and all names must be composed of uppercase letters and numbers. The project system code is composed of 3 English letters, and the category keyword of the equipment is also composed of 3 English letters. The equipment type or attribute as the specific type of the main equipment can be composed of letters and Arabic numerals, and the professional keywords can be split into multiple fields according to the characteristics of different professions, separated by "". In principle, the same name is used for equipment of the same model and specification. If there are differences in the appearance of the model due to different installation methods or layout adjustments, "_A (uppercase English serial number)" is added to the name.

[0050] Second, in terms of classification principle, power grid projects can be divided into substation projects, overhead line projects and cable line projects according to project types. Each project type can be systematically divided into four levels according to professional disciplines, namely, level I system, level II system, level III system and level IV system, where level I system directly corresponds to the project type. The specific system division principle is shown in the figure. Encoding is performed according to the system concepts involved in the four levels of system division. Taking "primary equipment" as an example, the level I system "substation project" is coded as "TSE", the level II system "electrical engineering" is coded as "EEG", the level III system "electrical primary" is coded as "PEL", the level IV system "primary equipment" is coded as "PEE", and the IFD code of "primary equipment" is "TSE_EEG_PEL_PEE".

[0051] Third, BIM components and equipment are the basic elements of projects and systems. The V-level system classifies equipment and materials, and the VI-level system classifies them according to the attributes or characteristics of the equipment. Taking the main transformer belonging to the "primary equipment" system as an example, the category keyword is "transformer", coded as "MTF", and the equipment type is "main transformer", coded as "MT", so the IFD code of the main transformer is "TSE_EEG_PEL_PEE_MTF_MT".

[0052] This project sorts out the classification and grading requirements of concepts in power grid engineering and encodes them according to specific naming rules to achieve power grid engineering data classification and coding.

[0053] (4) IDM Standard

[0054] IDM (Information Delivery Manual) is a method for defining and textualizing practical application purposes and corresponding data requirements. IDM can be used to express in detail the information data required by specific roles in different fields at various stages of the entire life cycle, and to break down relatively abstract industry requirements into a human-readable information requirement network. IDM defines the process relationship at each stage of a specific business and the requirements for model information at each stage. The complete IDM standard mainly consists of five parts: process map, exchange requirement, functional component, business rules and verification test. The core is the process map and exchange requirement. For the specified work requirements, the process map defines the participating roles and information exchange nodes. The exchange requirement explains the specific information exchange details of the process map, so that BIM users can exchange information and give detailed text descriptions. The functional component is the IDM data information unit, and a single exchange requirement is composed of several functional components. Business rules provide multiple constraints for a process. The verification test verifies whether each exchange requirement is accurate and met.

[0055] 2. IFC-GRID Standard Principles

[0056] The IFC-GRID standard research should follow the following basic principles:

[0057] (1) The standard architecture should be consistent with the overall infrastructure architecture.

[0058] (2) The standard should cover all professional fields related to power grid engineering, including primary and secondary electrical engineering, intelligent auxiliary control, cables and accessories, building structure, HVAC, water supply and drainage, fire protection, ground wires, insulator hardware, foundations, towers, cable line engineering, cable trenches, power tunnels, work wells, etc. in substation engineering.

[0059] (3) The standard should cover the entire life cycle of power grid project design, construction, and operation and maintenance.

[0060] (4) The standard is aligned with international information standards, compatible with the industry-recognized IFC standard, and incorporates the implementation characteristics of domestic power grid engineering projects.

[0061] (5) Try to use the existing data structure of the IFC standard to minimize the number of extended information models, reduce development costs, and improve reusability.

[0062] Building IFC extensions requires structural decomposition of power grid projects. Structural decomposition is mainly aimed at specific local models. The organizational framework and model management capabilities of the project are reflected in the local model of the project. In general, a project can be decomposed into a spatial structure and a functional structure. The spatial structure is used to express the organizational structure of the project in terms of spatial concepts, and is usually decomposed based on spatial proximity. The spatial structure of a project can be divided into multiple levels, and a spatial structure hierarchical model can be established through a one-to-many aggregation relationship. The functional structure is used to express a collection of elements that are scattered in the same project but have common functions and purposes. It is often used to analyze the functional collection and decomposition of the project. There is no geometric / topological combination form, and any specific object has no specific position relationship in the functional structure. A component is an instantiation of a type object, which is used to describe the components of each entity generated in the engineering activity and has geometric information and attribute information. A component can be logically contained in a spatial structure or a functional structure. A type object contains geometric information and attribute information shared by objects of the same type.

[0063] Building IFC extensions requires functional decomposition of power grid projects. Functional decomposition decomposes power grid projects into different sub-projects to facilitate simultaneous multi-threaded research on projects. Combined with the professionalism of power grid projects, they can be divided into substation projects, overhead line projects, and cable line projects according to their project types. Each type of project is further divided into systems from large to small according to the information structure distribution of power grid projects, which can be divided into Level I system (grid level), Level II system (engineering level), Level III system (professional level), Level IV system (system level), Level V system (equipment, material level), and Level VI (attribute level, which can be infinitely expanded attributes and feature levels).

[0064] Based on the existing IFC4.3 standard and the decomposition of power grid projects, 4IFC-GRID can further determine the new entities, attributes and relationship definitions on the six conceptual layers of IFC that need to be implemented. For example, the domain layer adds substation engineering, overhead line engineering, and cable line engineering domain modules; the shared module of cables and accessories is added to the shared layer; and the corresponding product extensions and geometric resources, material resources, and measurement resources are added to the core layer and resource layer according to actual needs.

[0065] Finally, the above concepts are expanded to be compiled and formed into a structured, machine-readable standard definition form using the EXPRESS description language.

[0066] In order to form a standard IFC-GRID mode, this embodiment adopts the form of directly extending IFC data entities (adding entities, types, etc.) to perform equipment expansion in the field of power grid engineering.

[0067] 3. Digital processing of BIM information based on IFC-GRID standard

[0068] When digitalizing BIM information based on the IFC-GRID standard, it is necessary to parse and integrate the component geometry data, component display data, component attribute data, and association relationship data of the IFC general standard, and add the IFC-GRID standard extension content on this basis, and finally realize the exchange and parsing of standard data in the domestic BIM basic empowerment platform for power grid projects based on the IFC-GRID standard. In the specific technical implementation, by deeply analyzing the basic syntax of the IFC EXPRESS language and the Schema entity information description in the IFC-GRID standard, the extended category and the custom entity information related to the power grid project are accessed. When performing the conversion or parsing action, the IFC extended entity of the power grid project category is obtained through the Exp file content, and during the conversion, the geometry data, display data, and attribute data are specially processed respectively, and passed to the IFC-GRID standard model in the Grep mode as much as possible; when parsing, the data loss between the IFC-GRID standard and the design model is minimized as much as possible, and the geometry information and attribute information are assembled by creating the corresponding instance, and the design model content is finely expressed in the model space in combination with the display data.

[0069] 3.1. Geometric data adaptability processing

[0070] In the general IFC standard, various types of geometric model data can be stored. Among them, Curve2D, GeometricSet, and GeometricCurveSet are used to describe models composed of basic graphics elements such as points, lines, and surfaces; SurfaceModel is used to describe surface models; and SolidModel is used to describe solid models, which can be subdivided into SweptSolid, Brep, CSG, Clipping, AdvancedSweptSolid, and other types.

[0071] For three-dimensional solid models, the most basic and commonly used shape representation methods are: boundary representation entity (Brep), swept solid (SweptSolid) and constructed solid (CSG), three examples of expression. Brep uses boundary surface constraints to represent a three-dimensional object, which is usually used to represent some more complex entities; swept solid adopts implicit modeling methods to create a three-dimensional entity by stretching and rotating a two-dimensional section; and CSG uses some basic objects or primitives (spheres, cylinders, cones) and the results of a series of Boolean operations (difference, union and intersection) to represent a three-dimensional object, but it relies on predefined objects and primitives, and the objects formed are relatively complex. In the power grid engineering model, after studying the geometric modeling features of power grid engineering models, equipment, facilities, etc., the conventional modeling is described by boundary representation entity (Brep) and swept solid (SweptSolid), and the complex model is described by surface model SurfaceModel, which finally provides the expression and data exchange of the geometric data of the overall power grid engineering model.

[0072] In order to meet the application of IFC-GRID standard, the geometric expression needs to be not only analyzed internally, but also output externally. The purpose of analysis is to be able to reconstruct IFC objects within the platform, and the purpose of conversion is to pass the digital model of power grid engineering to downstream professionals or links in the form of IFC-GRID standard, so as to achieve accuracy and consistency in data of the model.

[0073] 3.2. Geometric data adaptability processing

[0074] In the general IFC standard, display data includes geometry-based shading styles and object-based material styles. During the data conversion and parsing process, these display data need to be reorganized and associated with geometric entities, and ensure their correct representation and parsing in IFC-GRID. The domestic BIM basic enabling platform for power grid engineering provides an interface to convert the general IFC standard IfcProductRepresentation into a set of Geometry objects within the platform, including its style data. There are two ways to express the style data IfcStyleItem. One is to associate IfcMaterialDefinitionRepresentation, and then set the style association through IfcMaterial and IfcProduct; the other is to directly associate the model's geometric data with IfcGeometryRepresentationItem.

[0075] The display modes supported in IFC-GRID are divided into two modes: shaded display and material mapping display. For shaded display, the processing is relatively simple. You only need to pay attention to the fact that the color component data recorded in the IFC-GRID standard file are all normalized floating-point numbers. In this mode, the material with the map can also be displayed with the material base color as the unified rendering color of the model surface; for the material mapping display mode, it is relatively complex and is divided into three storage methods: picture link, binary stream, and pixel; the picture link can be a local path or a network path; the binary stream is stored in text represented in hexadecimal. Similarly, the IFC standard does not specify the compression method, which takes up a lot of space; the pixel method directly stores the color value of each pixel in text format, which takes up the most space; however, in the existing platforms that support general IFC file parsing and preview, there is little support for the form of picture links. The domestic BIM basic enabling platform for power grid engineering needs to consider loading performance, display optimization and other aspects. Therefore, the storage method of picture links has been supported, which can support IFC-GRID's display data design to be more flexible.

[0076] Due to the complexity of power grid engineering components, it is necessary to be able to display the internal structure of the components in many scenarios. For the underlying 3D graphics engine, the line hidden line algorithm is usually provided for 2D drawing of 3D models, and a customized dotted line style can be used to express the internal structure.

[0077] Based on the overall performance perspective of the domestic BIM basic empowerment platform for power grid projects based on IFC-GRID data support, the principle of geometric sharing needs to be applied. Therefore, when the platform parses the geometry, it returns the corresponding data when encountering a reference, including the transformation matrix, the referenced Entity Id, etc. When customizing business functions, this information can be updated to create a mapping from Entity Id to referenced Element Id, and then create a reference node to facilitate geometric sharing and display merging of components based on the same Entity Id, thereby improving the display performance of the empowerment platform.

[0078] 3.3. Attribute data adaptability processing

[0079] In the general IFC standard, the extended customization of object property data is generally achieved by defining new property sets (IfcPropertySet) and property types (such as IfcPropertySingleValue, IfcPropertyEnumeratedValue). The specific steps include creating new property sets to contain properties for specific requirements, defining new property types to meet project requirements, and then associating these property sets to IFC objects, and ensuring their correct representation and parsing in IFC files. These are also reflected in the IFC-GRID standard. Therefore, this route is also needed in the conversion and parsing of the IFC-GRID standard model to ensure data integrity and interoperability.

[0080] During the IFC-GRID extended object conversion process, the geometry does not change the modeling method of the existing components in the enabling platform. The original modeling method is re-described using the standard language of IFC. The object attributes also use attribute sets and attribute extensions to describe the entity characteristics. It is necessary to map the internal attributes in the design model to the attribute set of the IFC standard or the non-standard attribute set defined in IFC-GRID. This includes extracting and converting the attributes of each object, converting them into the corresponding attribute set and attribute type, and converting the attributes in the internal data structure (such as material, cost, performance parameters, etc.) into IFC attribute sets (such as IfcPropertySet) and specific attribute types (such as IfcPropertySingleValue). In this process, it is necessary to ensure the correctness and consistency of the attribute values, and handle possible unit conversions (such as length units, area units, etc.). The categories defined by the IFC-GRID standard extension should be converted according to the attribute set designed in the Schema to obtain accurate and unified digital model data.

[0081] Due to the need to be compatible with the extended IFC-GRID standard, the domestic BIM basic enabling platform for power grid projects must have the ability to write non-IFC standard attributes so that non-standard IFC attribute sets can be imported when creating components through IFC-GRID standard model files during the parsing process. The IfcPropertySet attribute can be set to each IFC node, and the content of IfcPropertySingleValue can be presented using a single attribute and attribute value. Considering the file size of the IFC-GRID model and the data conversion performance, the geometry, attribute and other information of the components referenced by the geometry are also reused and compressed during data conversion.

[0082] In the specific technical implementation, we deeply understand the basic syntax of IFC EXPRESS language, access the extended categories and customized entity Schema information described by Express. When executing the export action, we obtain the IFC extended entity of the power grid engineering category by parsing the IFC-GRID standard in the Exp standard file, and create the corresponding instance and attributes during export to achieve the purpose of extension. The main steps are as follows:

[0083] (1) Understand the basic syntax of the EXPRESS language and be familiar with the basic syntax and rules of the EXPRESS language, including data types, keywords, entity definitions, etc. The IFC Schema file mainly describes model information through entities defined in the EXPRESS language. The EXPRESS information modeling language is the foundation and core of the Standards for the Exchange of Product Model Data (STEP) and is mainly used for object-oriented information description. Unlike other object-oriented programming languages, the EXPRESS language sacrifices the executable degree of some codes, while greatly improving the computer's readability of the described information.

[0084] (2) Read and parse the EXPRESS file definition generated by the IFC-GRID standard: Use an appropriate programming language (such as Python, C++, etc.) to read the EXPRESS file definition and use the corresponding parser to parse it into operable code. IFCSchema aggregates the abstract entities formed by various things in the project through the EXPRESS language and specifies the mapping rules between various entities and the BIM model. This stage is to explain this mapping rule.

[0085] (3) Extracting entity information: Once the EXPRESS file is successfully parsed, the entity information defined in it can be extracted, including mapping rules for entity type, geometry, style, attributes, relationships, etc. This information will be used to create enabling platform model entities or build IFC-GRID instance objects based on model entities. When the program is parsed, this rule will be called to complete the mapping between the design model information and the IFC-GRID standard to achieve data conversion.

[0086] (4) Implementation of IFC-GRID standard model data exchange: Based on the extracted entity information, the mapping rules specified in the Schema file are applied to create actual IFC entity instances, which usually involves assigning unique identifiers to entities, setting entity attributes, and establishing relationships with other entities. The power grid engineering model object instance will reflect clear geometric shapes and specific spatial relationships, fully understand the expression of information related to the geometry of the three-dimensional model, accurately and effectively extract this information from the model file for the three-dimensional model geometry and convert it into the desired expression method in the IFC-GRID standard, or restore it to the instance object in the three-dimensional model based on the geometric shape and spatial relationship expression implemented in the IFC-GRID standard description.

[0087] Example 2

[0088] This actual example provides a BIM information digital processing system based on the IFC-GRID standard, including a memory and a processor, wherein the memory stores a computer program, and the processor calls the computer program to execute the steps of the BIM information digital processing method based on the IFC-GRID standard as described above.

[0089] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A BIM information digital processing method based on the IFC-GRID standard, characterized in that: The IFC-GRID standard is to expand the data structure based on the IFC standard and to connect with the types in the external classification system. The method includes the following steps: Obtain BIM data stored in IFC standard to be processed; The geometric model data in the BIM data is converted into shape expression in the form of boundary representation entities, swept entities, construction entities and surface models. The boundary representation entity uses boundary surface constraints to represent three-dimensional objects; the swept entity uses an implicit modeling method to stretch and rotate a two-dimensional section to create a three-dimensional entity; the construction entity represents a three-dimensional object by performing Boolean operations on objects or primitives; The display data in the BIM data is converted into a shaded display and a material mapping display, wherein the conversion process of the shaded display is to convert the color component data in the display data into normalized floating point numbers; the conversion process of the material mapping display is to convert the display data into storage in the form of picture links, binary streams or pixels; The attribute data in the BIM data is expanded and customized, including object expansion and object attribute expansion. The object expansion is re-described in the IFC standard language, and the object attribute expansion describes the entity characteristics by defining new attribute sets and attribute types.

2. The BIM information digital processing method based on the IFC-GRID standard according to claim 1 is characterized in that: During the geometric model data conversion process, the BIM data is also classified to distinguish whether it is a conventional model or a complex model. If it is a conventional model, the geometric model is described using boundary representation entities and swept entities; if it is a complex model, it is described using a surface model.

3. The BIM information digital processing method based on the IFC-GRID standard according to claim 1 is characterized in that: During the shading display process, the material with the map is also displayed with the material base color as the unified rendering color of the model surface.

4. The method for digital processing of BIM information based on the IFC-GRID standard according to claim 1, characterized in that: The image link in the conversion process of the material map display is a local path or a network path; the binary stream is stored in text represented by hexadecimal; the pixel method stores the color value of each pixel in text.

5. The method for digital processing of BIM information based on the IFC-GRID standard according to claim 1, characterized in that: The display data conversion process also includes expressing the internal structure in a dotted line style through a line blanking algorithm.

6. The method for digital processing of BIM information based on the IFC-GRID standard according to claim 1, characterized in that: The extended customization process of the attribute data specifically describes the extended category and the customized entity Schema information in an Express manner. When the export action is executed, the IFC extended objects and attributes of the power grid engineering category are obtained by performing IFC-GRID standard parsing.

7. The method for digital processing of BIM information based on the IFC-GRID standard according to claim 1, characterized in that: The object property extension extracts and converts the properties based on the object, and converts the properties in the internal data structure into an IFC property set and property type.

8. The method for digital processing of BIM information based on the IFC-GRID standard according to claim 7, characterized in that: The attributes in the internal data structure include material, cost and performance parameters.

9. The method for digital processing of BIM information based on the IFC-GRID standard according to claim 7, characterized in that: The method further includes: determining whether the volume of the model file obtained after the BIM data processing is greater than a preset volume threshold, and if so, performing multiplexing and compression processing on the geometric model data and the attribute data.

10. A BIM information digital processing device based on the IFC-GRID standard, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and the processor calls the computer program to execute the steps of any one of the methods according to claims 1 to 9.

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