IFC Reference Guide for ArchiCAD 17 IFC Reference Guide for ArchiCAD 17 ® GRAPHISOFT Visit the GRAPHISOFT website at http://www.graphisoft.com for local distributor and product availability information. IFC Reference Guide for ArchiCAD 17 Copyright © 2013 by GRAPHISOFT, all rights reserved. Reproduction, paraphrasing or translation without express prior written permission is strictly prohibited. Trademarks ArchiCAD® is a registered trademark of GRAPHISOFT. All other trademarks are the property of their respective holders. IFC Reference Guide for ArchiCAD 17 Contents Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Model View Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 File Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 IFC Data Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 IFC Element Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 IFC-Related Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 Working with IFC Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32 Export Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74 Import Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79 Change Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85 IFC Translators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91 Model Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108 GRAPHISOFT IFC Reference Guide for ArchiCAD 17 3 Contents 4 GRAPHISOFT IFC Reference Guide for ArchiCAD 17 Introduction IFC - Industry Foundation Classes - is a neutral file format that makes it possible to exchange information between different CAD systems and other systems in the building and facility management sectors. The IFC format is ISO-certified and can be integrated into any existing quality assurance polices your office may have. IFC is developed in part by the IAI - the International Alliance for Interoperability. Today there are over 600 members with 13 chapters around the world. For more information, see: http://www.buildingsmart.com/. GRAPHISOFT has played an active role within the IAI organization since 1996 and supports the IFC standard, which enables ArchiCAD to communicate with other disciplines within the context of the building model, and to coordinate a building project entirely in 3D. The building model can also be exported back to literally hundreds of other systems that support IFC. BIM, or “Building Information Modeling,” is one of the biggest advances in the building industry’s working methods since the introduction of CAD software. BIM is NOT synonymous with 3D projects. Three-dimensional geometric representation is only one part of the digital deliverables. A project includes non-graphical information, such as calculations that are used in surveying, facility management and energy calculation. A prerequisite for a successful BIM project is that intelligent information can be exchanged between different software and even operating systems, throughout the stages of the building process. This interoperability demands a neutral file format with an open standard that supports different systems. IFC is such a system, enabling us to synchronize building models between the disciplines much more easily. With its user-friendly interface and wide latitude for customization, ArchiCAD enables users to communicate in an efficient way, to focus on the needed elements and to locate any errors in design development via IFC data exchange. This chapter has been created to provide ArchiCAD users an insight into the IFC standard and how it works in ArchiCAD. Model View Definitions File Types IFC Data Types IFC Element Types IFC-Related Functions Working with IFC Data Export Functions Import Functions Change Detection IFC Translators Model Filter GRAPHISOFT IFC Reference Guide for ArchiCAD 17 5 Model View Definitions Industry Foundation Classes (IFC) are the open and neutral data format for openBIM. ArchiCAD supports the import, export and data structure of the latest IFC release: IFC2x Edition 3 (third release of the IFC 2x Platform, IFC2x3 for short) - more specifically, its latest version, the so- called Technical Corrigendum 1, published in July 2007. An IFC View Definition, or Model View Definition, MVD, defines a legal subset of the IFC Schema and provides implementation guidance or agreements for all IFC concepts (classes, attributes, relationships, property sets, quantity definitions, etc.) used within this subset. It thereby represents the software requirement specification for the implementation of an IFC interface to satisfy the Exchange Requirements. Model View Definitions are either defined within buildingSMART International, or by other organizations and interest group. ArchiCAD IFC Export and Import supports the following Model View Definitions: • The Coordination View was the first Model View Definition developed by buildingSMART International and is currently the most widely implemented view of the IFC scheme. The main purpose of the Coordination View is to allow sharing of building information models among the disciplines of architecture, structural engineering, and building services (mechanical). It contains definitions of spatial structure, building, and building service elements that are needed for coordinating design information among these disciplines. The IFC2x3 Coordination View is the built-in and default standard supported by ArchiCAD. • The Coordination View (Surface Geometry) is a simplified publishing format (i.e. a subset) of the Coordination View. This format is suitable for viewing (since all IFC viewers support this format), design coordination, clash prevention during design, and clash checking. “Coordination View (Surface Geometry)” means that every element will be exported with its BREP (boundary representation) geometry. This method comes closest to reproducing the real shape of the element, together with its specialized sections, connections and solid operations. (However, the element’s parameters are lost, and BREP elements from an imported IFC file are transformed into non-editable elements.) Note: In earlier versions, the Coordination View (Surface Geometry) was known as Simplified view (BREP only). • The Basic FM Handover View is an extended version of the Coordination View (developed by buildingSMART) that defines the general requirements for design applications to enable the handover of facility management information. The basic scope can be summarized as the space and equipment list for the spatial and technical systems of a facility. Technically, the Basic FM Handover View fulfills the following requirements above and beyond those of the abovementioned Coordination View: ability to assign furnishing and equipment components to spaces (Space Containment, IFC System), to assign spaces to zones (IFC Zone), to assign a classification to spaces and components (Classification Reference), to assign manufacturer base properties to components (standard and custom IFC Properties), to assign doors and windows to spaces (Space Boundaries), to assign type information for components (IFC Type Product) and to export base quantities for all project components and spatial structures. This MVD is required in various projects defined by buildingSMART and other organizations. An example is the COBie (Construction-Operations Building information exchange), a 6 GRAPHISOFT IFC Reference Guide for ArchiCAD 17 specification used in the handover of Facility Management information. It is a spreadsheet data format for the delivery of a subset of building model information, rather than geometric model information. ArchiCAD’s BIM-quality models and IFC data exchange capabilities produces data output that is easily converted into COBie documentation, with the help of free or commercial conversion programs. • There are several other Model View Definitions (generally the extended versions of the Coordination view) specified by organizations or development teams outside of buildingSMART International. An example is the Concept Design BIM 2010 model view definition that is supported/required by the General Services Administration (US GSA), Statsbygg (Norway) and Senate Properties (Finland). The additional MVDs require programs to provide IFC data above and beyond those of the Coordination View standard - such extra data include Classification Reference, Space Occupant, Actor, System and Time Series Schedule Assignments, and specific property sets and properties. ArchiCAD’s IFC interface provides the possibility to define, export and import these data types. As a result, users will be able to fulfill for example the GSA-specific classifications according to various OmniClass classes, Statsbygg and Senate Properties regulations. For more information, see IFC Data Types and Working with IFC Data. All Model View Definitions can be extended by add-on model view definitions which support additional exchange requirements: • the Quantity Take-off add-on view adds the ability to transmit base quantities for all spatial and building elements • the Space Boundary add-on view adds building elements to space relationships to support models in thermal and energy analysis • the 2D Annotation add-on view supports the exchange of additional 2D element representations and annotations of building models ArchiCAD supports all of these additional data types. See Export Options of IFC Translators. GRAPHISOFT IFC Reference Guide for ArchiCAD 17 7 File Types ArchiCAD supports the export and import of the following IFC data file formats: • .ifc: the default IFC exchange format using the STEP physical file structure • .ifcZIP: IFC data file using the ZIP compression algorithm. It is the compressed version of .ifc or .ifcXML. An .ifcZIP file usually compresses an .ifc down by 60-80% and an .ifcXML file by 90-95%. Note: .ifcZIP is compatible with e.g. Windows compressed folders, WinZip, etc. So if the recipient cannot read .ifcZIP, then a ZIP extractor application can open the file into .ifc or .ifcXML format. • .ifcXML: IFC data file using the XML document structure. This format is recommended for architects whose partners’ applications cannot read the original .ifc format, but can manage XML databases (such as budget, energy calculations, etc.). This format delivers the same model information as the plain .ifc format, but the elements and their properties are stored in a more informative structure. An .ifcXML file is normally 300-400% larger than an .ifc file. 8 GRAPHISOFT IFC Reference Guide for ArchiCAD 17 IFC Data Types This chapter summarizes the main IFC data types available in ArchiCAD. IFC Entity IFC Container IFC Type Product IFC Model Hierarchy IFC Attributes IFC Classification Reference IFC Assignments GRAPHISOFT IFC Reference Guide for ArchiCAD 17 9 IFC Entity In an IFC model, the project information (generated, for example, from an ArchiCAD project) is represented as a set of IFC Entities - such as elements, surfaces, and their relationships. Each IFC Entity (for example, an IfcWall) includes a fixed number of IFC Attributes, plus any number of additional IFC Properties. The IFC scheme encompasses several hundred entities, of which the building element-type entities (such as IfcWall and IfcColumn) represent only 25. Some IFC Entities express characteristics of other entities. Some of these correspond to ArchiCAD attributes. These correspondences are mapped automatically when the IFC model is generated or exported, or when the IFC model is imported. ArchiCAD Attribute IFC Entity Layer IfcPresentationLayerAssignment Building Material IfcMaterial Surface IfcSurfaceStyleRendering Composite IfcMaterialLayerSet (extruded geometry) or IfcMaterialList (BREP geometry) Profile IfcProfileDef 10 GRAPHISOFT IFC Reference Guide for ArchiCAD 17