Industry Foundation Classes Data Research Articles

Generic Language for Partial Model Extraction from an IFC Model Based on Selection Set

During data sharing and exchange of building projects, the particular business task generally requires a part of the complete model. This paper adopted XML schema to develop a generic language to extract the partial model from an Industry Foundation Classes (IFC) model based on the proposed Selection Set (called PMESS). In this method, the Selection Set was used to integrate users’ requirements, which could be mapped into IFC data. To ensure the validity of the generated partial IFC models in syntax and semantics, seven rules—including three basic rules for a valid IFC file, three extraction rules based on the Selection Set, and a processing rule for redundant information—were defined. Through defining PMESS-based configuration files, the required data can be extracted and formed as a partial IFC model. Compared with the existing methods, the proposed PMESS method can flexibly extract the user-defined required information. In addition, these PMESS-based configuration files can be stored as templates and reused in other tasks, which prevents duplicated work for defining extraction requirements. Finally, a practical project was used to illustrate the utility of the proposed method.

HBIM-GIS Integration: From IFC to CityGML Standard for Damaged Cultural Heritage in a Multiscale 3D GIS

This study describes the technical-systemic and conceptual-informative interoperability tests for the integration of a Historic Building Information Modeling (HBIM) model in a 3D Geographic Information System (GIS) environment aimed to provide complete and useful documentation for multiscale analyses on cultural heritage particularly exposed to risks. The case study of the San Lorenzo Church in Norcia (Italy) has been chosen given the urgent need to update the existing documentation for its protection and conservation issues, due to the extensive damage suffered after the series of earthquakes that occurred in central Italy starting from summer 2016. Different tests to evaluate two levels of conceptual interoperability (technical and semantic) when importing the HBIM model into a GIS environment were performed, whether with commercial software or with open source ones (ArcGIS Pro and QGIS, respectively). A data integration platform (Feature Manipulation Engine, FME) has been used for converting the IFC (Industry Foundation Classes) data format into the GML (Geography Markup Language) format, in order to obtain a unique and unified model and vocabulary for the 3D GIS project, structured with different levels of detail, according to CityGML standard. Finally, as HBIM-GIS integration is considered, the loss of geometric and informative data has been taken into account and evaluated.

A Graph‐Based Method for IFC Data Merging

Collaborative work in the construction industry has always been one of the problems solved by BIM (Building Information Modeling) technology. The integration of IFC (Industry Foundation Classes) data as a general building information standard is one of the indispensable functions in collaborative work. The most practical approach of merging IFC data depends on GUID (Global Universal Identifier) comparison at present. However, GUID is not stable in current applications and often changes when exported. The intact representation of relationships between IFC entities is an essential prerequisite for proper association of IFC entities in IFC mergence. This paper proposes a graph‐based method for IFC data merging. The IFC data are represented as a graphical data structure, which completely preserves the relationship between IFC entities. IFC mergence is accomplished by associating other data with an isomorphic graph that is obtained by mining the IFC graph. The feasibility of the method is proven by a program, and the method can ignore the impacts of GUID and other factors.

BIM assisted Building Automation System information exchange using BACnet and IFC

Smart buildings are the trend of the next generation's commercial buildings that link different building systems together with the Building Automation System (BAS). Building information modeling (BIM) assists in data exchange and information flow. Previous research has explored BAS and BIM integration for energy management, building design optimization and operation, and building fault detection and diagnostics. However, it is rarely seen to design BAS or exchange BAS information in different project stages using BIM tools. The current design of the BAS system is either using 2D drawings based on AutoCAD or vendor customized tools. Unlike the other building systems, BAS seldom participates in design-build BIM cycle but blends into facility management in the later stage. To tackle this issue, this research aims to set a fundamental step to facilitate information exchange for BIM assisted BAS design and operation using one of the BAS open communication protocol named Building Automation and Control Networks (BACnet) and open BIM standard Industry Foundation Class (IFC). This paper leverages Information Delivery Manual (IDM) and Model View Definition (MVD) methodologies to define an IFC subset schema (a BACnet MVD) so that BAS information conforming to the BACnet protocol can be represented in IFC data model for information exchange throughout various project stages with BIM tools. Revit and a web browser were used to demonstrate the implementation of the BACnet MVD for BAS information exchange. In this way, BAS information represented in the open BIM standard can unlock the potential of future smart building information exchange and integration.

3D LANDSCAPE OBJECTS FOR BUILDING INFORMATION MODELS (BIM)

Abstract. Building Information Modeling (BIM) is a method for the digital collaborative design, construction and operation of buildings. However, in order to realize a complete view on needed work and expenses of a building, the surrounding landscape elements must be considered as well. Within this paper, the BIM authoring tool Autodesk Revit and the open BIM data model and exchange format Industry Foundation Classes (IFC) has been investigated for its capability to represent landscape elements like a terrain model, retaining walls, and ways. Therefore, a feasibility study has been carried out including the surveying of real-world landscape objects like terrain, buildings, ways and paths, playgrounds, and retaining walls, in order to use actual existing objects instead of idealized, theoretical elements. The aim was to develop and evaluate a workflow from the surveying over the modeling in BIM-able software to the export of an IFC data file. Therefore, the general modeling concepts of BIM and their suitability and limitations for representing landscape elements has been investigated. Experiences made within the project are discussed and first solutions and concepts are recommended. In addition, this paper reports from the buildingSmart International working group “Site, Landscape, and Urban Planning”, their current work and future goals, in order to extend IFC for landscape objects. Additionally, a concept for level of information need referring to landscape elements is shown.

THE PATH FROM BIM TO A 3D INDOOR FRAMEWORK – A REQUIREMENT ANALYSIS

Abstract. Building Information Modelling is a new technology and tool for researchers in Architecture/Construction/Engineering (ACE) fields, and it is designed to organise the collaboration between different parties and manage all types of information regarding buildings. A standardized data model of BIM named Industry Foundation Classes (IFC) has been proposed to describe building & construction related information and facilitate the interoperability of building data. As IFC contains plenty of building information, further spatial analysis can be applied in geographical information system (GIS) with these information. Current research has mainly discussed the requirements about data translation from BIM to GIS. However, more specific requirements on the functionalities of a generic 3D indoor framework need to be considered with IFC data. Although this research is in the initial stage, we investigate the use of BIM IFC for the 3D indoor framework, especially on the data translation from IFC to the framework, data management in the framework and IFC data for 3D spatial analysis. Requirements are analysed in four aspects: 1) automation of indoor vector map generation; 2) data management for the framework; 3) environmental analysis of the framework; and 4) safety analysis of the framework. According to these requirements, new modules need to be developed. In the future, based on IFC data we will conduct tests of data transformation, design a data model for the 3D indoor framework and develop a prototype to demonstrate the planned spatial analysis functionalities.

Modeling of Macroscopic Building Evacuation Using IFC Data

Presently, most models of crowd evacuations within a building are created manually. This is inefficient. To address this issue, this paper focuses on the differences and relationship between industry foundation classes (IFC) and the macroscopic network model for evacuation (MNME), and studies the mapping and construction methods used to convert entity objects into nodes and arcs in the MNME. Furthermore, corresponding attribute information in the MNME are established from IFC. Based on this process, the MNME is created and used as an input to EVACNET4 to obtain simulation results. Finally, the results, together with a 3D building model, are expressed in a unified environment. Our study results show that a network as well as the relevant attributes can be automatically generated from IFC, and can be adapted to different working conditions. The method proposed in this paper can automatically map the semantic information model to the MNME and the simulation result as well as the building model can be integrated in a Geographic Information System (GIS) environment.

Intelligent generation of indoor topology (i-GIT) for human indoor pathfinding based on IFC models and 3D GIS technology

Abstract Indoor topology is the basis for most indoor location-based services, such as wayfinding in shopping malls, escape route planning, and passenger transfer in transport stations. Currently, however, indoor networks for wayfinding by people have not yet been developed to a standardized representation as street maps have been, but many studies have attempted to develop indoor network models for indoor LBS. A complete indoor network includes both floor-level paths and non-level paths, such as stairs, elevators, escalators, ramps, and so on. Most existing studies, however, have explored floor-level paths; few studies have considered non-level paths. Many studies have used 3D building models based on Industry Foundation Classes (IFC) to develop algorithms for generating paths, but most of them require the IFC model to contain semantic elements for the spatial relationships among building components, which means extra efforts are needed when preparing the IFC Model from the original building model. Moreover, most algorithms dealing with floor-level paths use simplified floor plans as the input, which are different from the real data retrieved directly from IFC models. All of these requirements and assumptions add to the cost of producing an indoor network. In this study, we propose an approach called i-GIT to produce a graph-based indoor network including floor-level and non-level paths from IFC-based building models. i-GIT requires only the geometric information of IFC data models to automatically identify indoor space boundaries as well as to produce six categories of indoor paths. The innovation of this study is that it includes novel algorithms to produce non-level paths, and introduces the polygon regularization on indoor space boundaries to reduce the number of excessive nodes before applying Constrained Delaunay Triangulation to produce level paths. Three campus buildings and a Taiwan High Speed Rail (THSR) station were chosen to validate the proposed approach. Multiple OD pairs in one of test cases were randomly selected to find the shortest routes using the paths generated by i-GIT. Compared with paths manually drawn using the principles of Medial Axis Transform (MAT) and the route lengths from actual measurement, the average path availability is higher than 96%, while the average error of route lengths based on generated paths is approximately 5%. The results showed that i-GIT was able to accurately and effectively produce a complete indoor network.

Applying novelty detection to identify model element to IFC class misclassifications on architectural and infrastructure Building Information Models

Abstract Ensuring the correct mapping of model elements to Industry Foundation Classes (IFC) classes is fundamental for the seamless exchange of information between Building Information Modeling (BIM) applications, and thus achieve true interoperability. This research explored the possibility of employing novelty detection, a machine learning approach, as a way to detect potential misclassifications that occur during current ad hoc and manual mapping practices. By training the algorithm to learn the geometry of BIM elements for a given IFC class, outliers are detected automatically. A framework for leveraging multiple BIM models and training individual one-class SVM's was formulated and tested on four IFC classes. Performance results demonstrate the classification models to be robust and unbiased. The algorithms developed thus can be leveraged to check the integrity of IFC data, a prerequisite for BIM-based quality control and code compliance. Highlights The correct mapping of BIM elements to IFC classes is critical for IFC based interoperability. A framework is formalized for applying novelty detection to automate the checking of misclassifications. One-class SVM's are trained and tested on two architectural and two infrastructure IFC classes. Performance metrics indicate robust and unbiased models with high accuracy and true negative rates. Novelty detection is a superior approach to outlier detection in identifying misclassifications of BIM to IFC associations.

MVD based information exchange between BIM and building energy performance simulation

Abstract The process of preparing building energy performance simulation (BEPS) models involves repetitive manual operations that often lead to data losses and errors. As a result, BEPS model inputs can vary widely from this time consuming, non-standardised and subjective process. This paper proposes a standardised method of information exchange between Building Information Modelling (BIM) and BEPS tools using the Information Delivery Manual (IDM) and Model View Definition (MVD) methodologies. The methodology leverages a collection of use cases to initiate the identification of exchange requirements needed by BEPS tools. The IDM/MVD framework captures and translates exchange requirements into the Industry Foundation Classes (IFC) schema. The suggested approach aims to facilitate the transfer of information from IFC based BIM to either conventional or advanced BEPS tools (e.g. EnergyPlus and Modelica) through the development of a specific MVD that defines a subset of the IFC data model that deals with building energy performance simulation. By doing so, the potential of BIM-based simulation can be fully unlocked, and a reliable and consistent IFC subset is provided as an input for energy simulation software.

Removing duplicated geometries in IFC models using rigid body transformation estimation and flyweight design pattern

BackgroundThe digital process of Building Information Modeling (BIM) involves the creation and modification of CAD-based building models. The complexity of such models has been increasing steadily within the last few years. BIM Models are usually being exchanged using open and standardized data formats. In this context, the Industry Foundation Classes (IFC) are widely used. Therefore, software vendors provide interfaces for dealing with the IFC format. To obtain a high level of data integrity, however, IFC elements are often managed as completely distinct entities, which can result in the creation of multiple copies of identical pieces of information. Since the trend to provide web-based solutions for BIM applications is also becoming increasingly important, especially the conflict between available resource consumption and suitable response times must be considered. Although existing optimization algorithms can reduce the size of an IFC file by analyzing its structure syntactically, there is still the gap to detect identical pieces of geometries that are syntactically distinct. Also, when subsequently merging such geometries, the available sharing concepts must be questioned.MethodsThe contribution of this paper is twofold. On the one hand, we propose an algorithm to retrospectively detect identical geometries by estimating the rigid body transformation. On the other hand, we outline and evaluate the available possibilities for sharing geometries within the IFC data model. The so-called flyweight pattern is applied to provide and maintain the appropriate reuse of identical information.ResultsThe methodologies are exemplary demonstrated by modeling and optimizing a typical tunnel lining structure, which contains many repetitive elements. As a result, a noticeable reduction of storage and processing time can be measured.ConclusionsEstablishing BIM in large building projects, where complexity not only depends on variation and geometric detail, but also depends on enormous repetition of these elements, a significant benefit is expected.

Working with Open BIM Standards to Source Legal Spaces for a 3D Cadastre

Much work has already been done on how a 3D Cadastre should best be developed. An inclusive information model, the Land Administration Model (LADM ISO 19152) has been developed to provide an international framework for how this can best be done. This conceptual model does not prescribe the technical data format. One existing source from which data could be obtained is 3D Building Information Models (BIMs), or, more specifically in this context, BIMs in the form of one of buildingSMART’s open standards: the Industry Foundation Classes (IFC). The research followed a standard BIM methodology of first defining the requirements through the use of the Information Delivery Manual (IDM ISO29481) and then translating the process described in the IDM into technical requirements using a Model View Definition (MVD), a practice to coordinate upfront the multidisciplinary stakeholders of a construction project. The proposed process model illustrated how the time it takes to register 3D spatial units in a Land Registry could substantially be reduced compared to the first 3D registration in the Netherlands. The modelling of an MVD or a subset of the IFC data model helped enable the creation and exchange of boundary representations of topological objects capable of being combined into a 3D legal space overview map.

개방형BIM 데이터와 법규 자동화 검토 시스템 간 속성 매핑 체계 개발

Many countries have been developing BIM-based building code checking system and studies in the utilization of Industry Foundation Classes (IFC) in building code checking. IFC is the open standard of BIM format. Currently, there is a disadvantage that could not include all of the attribute for the regulations of each country and there is the problem with the interoperability of the different defined IFC approach between BIM software. This study focus on developing, derived object and property by comparing through domestic regulation and IFC2x3 specification provided by the buildingSMART and classified review type depending on the interoperability of derived information. According to classified review type, the IFC data structure was established and property mapping contents were developed by including BIM software compatible information and creating a type of review plan. When the developed property mapping contents are applied into BIM-based building code checking system, checking of the BIM data generated from various fields is made effective and thus improving the interoperability of information.

AN OBJECT-RELATIONAL IFC STORAGE MODEL BASED ON ORACLE DATABASE

With the building models are getting increasingly complicated, the levels of collaboration across professionals attract more attention in the architecture, engineering and construction (AEC) industry. In order to adapt the change, buildingSMART developed Industry Foundation Classes (IFC) to facilitate the interoperability between software platforms. However, IFC data are currently shared in the form of text file, which is defective. In this paper, considering the object-based inheritance hierarchy of IFC and the storage features of different database management systems (DBMS), we propose a novel object-relational storage model that uses Oracle database to store IFC data. Firstly, establish the mapping rules between data types in IFC specification and Oracle database. Secondly, design the IFC database according to the relationships among IFC entities. Thirdly, parse the IFC file and extract IFC data. And lastly, store IFC data into corresponding tables in IFC database. In experiment, three different building models are selected to demonstrate the effectiveness of our storage model. The comparison of experimental statistics proves that IFC data are lossless during data exchange.

AN OBJECT-RELATIONAL IFC STORAGE MODEL BASED ON ORACLE DATABASE

Abstract. With the building models are getting increasingly complicated, the levels of collaboration across professionals attract more attention in the architecture, engineering and construction (AEC) industry. In order to adapt the change, buildingSMART developed Industry Foundation Classes (IFC) to facilitate the interoperability between software platforms. However, IFC data are currently shared in the form of text file, which is defective. In this paper, considering the object-based inheritance hierarchy of IFC and the storage features of different database management systems (DBMS), we propose a novel object-relational storage model that uses Oracle database to store IFC data. Firstly, establish the mapping rules between data types in IFC specification and Oracle database. Secondly, design the IFC database according to the relationships among IFC entities. Thirdly, parse the IFC file and extract IFC data. And lastly, store IFC data into corresponding tables in IFC database. In experiment, three different building models are selected to demonstrate the effectiveness of our storage model. The comparison of experimental statistics proves that IFC data are lossless during data exchange.

Development of an IFC-based data schema for the design information representation of the NATM tunnel

A tunnel data schema employing the New Austrian Tunneling Method (NATM) is proposed to efficiently manage and exchange the design information of road tunnels between different computer environments. The data schema was developed by extending the Industry Foundation Classes (IFC) used as standards in Building Information Modeling/Model (BIM) projects. The design guidelines and tunnel drawings were analyzed in order to apply the design information of the NATM road tunnels. From the analysis results, the applicable IFC elements were identified through a comparative analysis with the existing IFC data schema, and new items were defined for the additional necessary elements. The newly defined elements were classified into the parts representing the information of the space occupied by the tunnel and that representing the information on components such as shotcrete, steel ribs, and concrete linings. The applicability of the developed schema was examined by using it to construct an experimental environment, in which information modeling was possible.

Generating IFC models from heterogeneous data using semantic web

Purpose – This paper aims to develop a framework to represent semantic web query results as Industry Foundation Class (IFC) building models. The subject of interoperability has received considerable attention in the construction literature in recent years. Given the distributed, semantically heterogeneous data sources, the problem is to retrieve information accurately and with minimal human intervention by considering their semantic descriptions. Design/methodology/approach – This paper provides a framework to translate semantic web query results into the XML representations of IFC schema and data. Using the concepts and relationships in an IFC schema, the authors first develop an ontology to specify an equivalent IFC entity in the query results. Then, a mapping structure is defined and used to translate and fill all query results into an ifcXML document. For query processing, the proposed framework implements a set of predefined query mappings between the source schema and a corresponding IFC output schema. The resulting ifcXML document is validated with an XML schema validating parser and then loaded into a building information modeling (BIM) authoring tool. Findings – The research findings indicate that semantic web technology can be used, accurately and with minimal human intervention, to maintain semantic-level information when transforming information between web-based and BIM formats. The developed framework for representing IFC-compatible outputs allows BIM users to query and access building data at any time over the web from data providers. Originality/value – Currently, the results of semantic web queries are not supported by BIM authoring tools. Thus, the proposed framework utilizes the capabilities of semantic web and query technologies to transform the query results to an XML representation of IFC data.

IFCCompressor: A content-based compression algorithm for optimizing Industry Foundation Classes files

As the commonly used open and neutral file format for Building Information Modeling (BIM) data, IFC (Industry Foundation Classes) aims to facilitate interoperability between various software platforms in the AEC industry. However, the IFC files generated from different systems often contain enormous redundant information, which will greatly limit IFC-based data storage and exchange, management, transmission and other applications. To address this issue, this paper presents a content-based compression algorithm, named IFCCompressor, for optimizing IFC data files. Its goal is to make a large IFC file as small as possible by reducing its redundant information. The algorithm is achieved through an iterative compression procedure based on an IFC model's tree structure. The optimization procedure can be lossless or be constrained by an error bound. Compared with pure compression (ZIP) regardless of information content, the presented algorithm starts with a comprehensive analysis of structure and content of IFC file, and then eliminates its redundant information without changing the original file format. Unlike partial model extraction methods, our algorithm results in a complete IFC model but with a more compact IFC physical file. In contrast with some commercial IFC optimization tools such as Solibri IFC Optimizer, the algorithm can make the size of IFC files smaller. The experimental results show that the algorithm is particularly effective for some office/residential building models with a large number of duplicated components. The compression rate with our algorithm is generally very high (the average is 40.32%) for tested cases. The online IFCCompressor tool and its demonstration can be accessed at: http://cgcad.thss.tsinghua.edu.cn/liuyushen/IFCCompressor/.

Development of an object model for automated compliance checking

Building designs in countries such as the United Kingdom are currently checked manually against a frequently changing and increasingly complex set of building regulations. This is a major task for designers and those bodies that are charged with enforcing the building regulations. As a result this can often lead to ambiguity, inconsistency in assessments and delays in the overall construction process. As the Architecture, Engineering and Construction (AEC) industry moves from 2D Computer Aided Design (CAD) drawings to more semantically rich Building Information Models (BIMs), the development of automated compliance checking systems for building regulations becomes achievable. A format well suited to the automation of compliance checking is that based upon Industry Foundation Class (IFC). IFC has been accepted worldwide as an inter-operability standard. However, whether the IFC data format can fully support the specialised needs of the England and Wales Building Regulations is still debatable. In order to automate their checking, building regulations first need to be interpreted from human-readable free text rules into a set of computer-implementable rules. This paper reviews previous research into automated code compliance-checking, identifies the key issues for future development, and focuses on the analysis of the England and Wales Building Regulations that relate to fire safety for dwelling houses, to determine and subsequently optimize the potential for automated compliance checking. Subsequently, a Building Regulation-specific, semantically rich object model, appropriate for the requirements of automated compliance checking has been developed for England and Wales.

BIM을 BEM으로 전환할 때의 문제점과 전망

Recently, interoperability between BIM (Building Information Model) and BEM (Building Energy Model) has been highlighted. Even though it has been widely recognized that there are significant potentials in BIM by data sharing and reuse, BIM has not been actively utilized for building energy simulation. With this in mind, in this paper, the authors investigated several issues: (1) limitation of Industry Foundation Class (IFC) and BIM authoring tools, (2) immature IFC data schema, (3) data mapping problem between BIM and BEM. Firstly, IFC files exported from major BIM authoring tools are not consistent with each other and don't include significant thermal parameters. In addition, building geometry, e. g. underground wall, is not properly exported. IFC data schema are not ready to describe detailed information on thermal and dynamic properties (efficiency, performance curves, etc.) of mechanical systems (HVAC, AHU), delivery systems (fans, pumps), and plants (boilers, chillers), which are very essential for BEM. Finally, most of the efforts on BIM-to-BEM are focused on data conversion (data-driven approach), without considering dynamic architectural design process which involves many different stakeholders. In near future, BIM-to-BEM interface should take into account design context and rational decision making so called 'process-driven approach'.