buildingSMART alliance Energy Information Exchange (ENERGie) Presentation

Energy Information Exchange (ENERGie) Presentation

DECEMBER 8, 2008

Session chair:
Francois Grobler


The Energy Information Exchange (ENERGie) projects goal is to harmonize the requirements of gbXML and the building elements of LEED within the context of an EnergyPlus compliant Model View Definition to provide a single life-cycle oriented exchange of energy analysis information. The work presented in this session extends the early design energy data exchange supported by the General Services Administration to include requirements for coordinated design. This session introduced the Model View Definition and provided demonstration demonstrations of various software pieces that will be used in the end-product.


The U.S. Army funded this development and demonstration.


The following presentations were given at the meeting:

Status: Information Requirements for LEED Design

There is growing interest in defining the information that must be transmitted from the design team to the LEED assessor and back. These exchange requirements are extensive, but the use of BIM models is expected to be increasingly important. The ENERGie project has developed process diagrams which highlight the exchange requirements in general terms and the functional parts which define the exact scope of the information required in technical terms. The analysis starts with the seven–part criteria:

Flow chart showing the analysis of Site Selection, Water Efficiency, Energy and Atmosphere, Materials and Resources, Indoor Environmental Quality and Innovation and Design Process

For more information, see

ENERGY MVD for Detailed Design

Currently BIM models exported to IFC should contain sufficient information for the analysis of the envelope performance. More detailed analysis, for example of the energy flows between zones and spaces, require more detailed exports. In particular the IFC file can contain information on the way spaces touch the fabric elements such as walls and slabs. For more detailed design it may also be necessary to know how each patch aligns with patches on the other side of the fabric element. The conventions for documenting these increasingly complex relationships are the subject of a 'model view definition' which is prepared to help BIM tool vendors include this information in their exports, and to help Energy analysis vendors to import this information.

For more information, see

gbXML and IFC

The preferred format for interoperability of facility information is IFC (ISO PAS 16739) developed by buildingSMART, which can be used for many interchanges during the facility lifecycle. An alternative format for interoperability is gbXML developed by Green Building Studio Inc., now owned by Autodesk, which is used specifically to transmit fabric and outline system information to Energy analysis packages.


In so far as the two standards can themselves be made interoperable, there will be a reduced risk that designers will be restricted in their choice of design application or analysis application. This freedom should benefit both designers and energy analysts. Designers have more freedom to choose their preferred BIM design application, and the energy analyst has more freedom to choose their preferred Energy analysis application, whilst still benefiting from reduced set-up times for their analysis applications. This should improve the transmission of the concept from the designer to the analyst and also the flow of results from the analyst back to the designer.


The primary pre-requisite for the deployment of this technology is in ensuring that facility designers and energy analyzers deliver their information in one of the interoperable formats. This expectation may need to be enforced by contractual terms, extra work items or separate negotiation. Education on the concepts and training in using the tools is vital. This is particularly necessary as interoperability depends on the more skillful and accurate exploitation of object based design tools for facility design, such as Bentley Architecture, Autodesk Revit, Vectorworks etc, and of analysis tools such as Green Building Studio, IES and Energy + .

The tools needed are available at zero cost.

Application Support for gbXML and IFC

Chart showing the interchange of IFC and gbXML. Above is an Exporting IFC box with EliteCAD, VectorWorks and Allplan listed; an Exporting IFC and gbXML box with Graphisoft Revit, Autodesk Revit and Bentley Architecture listed; and an Exporting gbXML box with Trane, TAS and GreenBuildingStudio listed. Below is an Importing IFC box with Bentley Architecture, Autodesk Naviworks, Solibri ModelChecker, EliteCAD, Vectorworks and Allplan listed; an Importing IFC and gbXML box with Autodesk Ecotect and Autodesk Revit listied; and an Importing gbXML box listed with Trane, TAS, Carrier, IES, DesignBuilder and GreenBuildingStudio listed.

(based on internet search performed May 2009)


gbXML is an XML format, IFC has an XML representation as ifcXML. XML is significant because the technology to read, write and transform XML has been standardized and is freely available. For example this project has built on a technology previously developed for USACE ERDC called 'bimServices'. 'BimServices' is a suite of command line utilities designed to effect systematic transformation of facility data. 'bimServices' uses the Microsoft .Net XSLT engine which could be replaced by other tools such as Saxon, Xalan, or AltovaXML. 'bimServices' uses a third party no-cost component 'ifcEngine' (developed by TNO Delft, Holland) primarily to convert IFC data between STEP (ISO 10303 part 21) and XML (ISO 10303 part 28) representations. This component is freely available subject to licensing conditions.

The key deliverables from the current project are the configuration "_fromGBxml.ifcxml.xsl" which embodies the mapping from the gbXML representation to ifcXML, and the configuration "_asGBxml.xml.xsl" which embodies the mapping from the ifcXML to gbXML representation.

C:\> Transform1 _fromGBxml.ifcxml.xsl example.xml
bimServices v2009.08.24 by AEC3 UK Ltd
using TNO IfcEngine for USACE ERDC.
Found   : example.xml (857919)
Found   : _fromGBxml.ifcxml.xsl (27317)
IfcProject          : ID0ED
IfcBuilding         : GKA-001
Created : example_fromGBxml.ifcxml (154549)
Created : example_fromXMpLant.ifc (4067)

C:\> Transform1 _asGBxml.xml.xsl example.ifc
bimServices v2009.08.24 by AEC3 UK Ltd
using TNO IfcEngine for USACE ERDC.
Found   : example.ifc (857919)
Created : example.ifcxml (154549)
Found   : _asGBxml.ifcxml.xsl (27317)
IfcProject          : ID0ED
IfcBuilding         : GKA-001
Created : example_asXMpLant.xml (4067)

Getting Started

The 'bimServices' suite is freely available from the website under Tools. This includes documentation on usage.

The configuration files to support interoperability are _fromGBxml.ifcxml.xsl dated 2009-09-16, and _asGBxml. xml.xsl dated 2009-09-16.

No support or warranty is offered for bimServices, ifcEngine or its configurations.

"bimServices" is currently based on the IFC2x platform which has been guaranteed stable for the last six years and underlies the current release IFC2x3 and the next release ifc2x4. This last standard will be submitted for full ISO endorsement. "bimServices" can be installed on end user machines supporting Windows, or it can be configured as services behind a web-based design collaboration services such as NIBS ProjNetSM. The deliverables are based on version 0.39 of the gbXML schema and the ifc2x3 release of IFC. Vendors may be supporting earlier versions.

Back to bSa Proceedings

Innovative Solutions for the Built Environment

Established by the United States Congress, the Institute’s mission is to unite the entire building community in advancing building science and technology.

Address 1090 Vermont Avenue, NW, Suite 700, Washington, DC 20005-4950

© 2020 National Institute of Building Sciences. All rights reserved.

Contact Us:
Phone: (202) 289-7800
Fax: (202) 289-1092

Follow us on: