Building Energy Modeling (BEM)

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There is currently 2 BIM format related to energy modeling : gbXML and IFC (using IfcRelSpaceBoundary2ndLevel) Most energy analysis software reads gbXML. Some read IFC. Generating geometry for gbXML and IfcRelSpaceBoundary is quite similar. Information contained in both format is different. There are significant challenges (in 2022) with IFC and space boundaries, BuildingSMART International is working to improve the situation by improving the Information Delivery Manual (IDM) for Building Energy Modelling (BEM). The current status (in 2022) can be seen in a video from bS Virtual Summit Spring 2021 in the presentation BR5 - Jeffrey Ouellette - Building Energy Modelling (BEM).

See the Category:Building_Energy_Modeling_(BEM) category for more general info and tools!

Note to editors: Add a gbXML vs IFC features comparison

Energy modeling workflow (/!\Work in progress/!\)[edit]

Modeling the building[edit]

Building need to be modeled with all data relevant to energy analysis :

  • Building geometry : Walls, Slabs, Doors, Windows, Spaces etc…
  • Energy data : Thermal transmittance, wall layers, thermal conductivity, solar transmittance, light transmittance etc…

Overmodelled building often lead to error and/or uselessly complex computation. A energy model should be simple and contain only energy relevant information.

BlenderBIM Add-on[edit]

BlenderBIM Add-on allows you to create, modify an IFC targeting energy analysis. You can either:

  • Rework an IFC coming from another authoring tool. This is probably the most efficient workflow currently. It allows you to enhance your model and fixes common known issues incoming from popular authoring software.
  • Create a model from scratch. You might want to take a look at topologic and related projects for more automation.

Energy specific geometry[edit]

An algorithm need to generate energy specific space boundaries

Export to common energy exchange formats[edit]

Software need provide an Ifc or gbXML.




Known issues[edit]

Warning Warning: lastly tested with Revit 2021. revit-ifc 21.2.1

IFC 2x3 and 4 :

  • export boundaries at middle of the wall instead of interior face.
  • roof boundaries are oversplitted if they host an element (eg. skylight / hole for lift top)
  • type B boundaries are not exported

IFC4 :

  • CorrespondingBoundary attribute is not filled
  • ParentBoundary attribute is not filled



By default ArchiCAD use IFC4 reference view MVD which do not contain IfcMaterialLayerSet(Usage). So layered wall will not contain thickness of each layer. Use a custom IFC translator using parametric

Known issues[edit]

Warning Warning: lastly tested with ArchiCAD 24

IFC 2x3 and 4 :

  • window and door boundaries are not coplanar with their host
  • There is no hole for window and door boundaries in their host
  • type B boundaries are not exported

IFC4 :

  • CorrespondingBoundary attribute is not filled
  • ParentBoundary attribute is not filled

Adaptation to local standards[edit]

Both IFC and gbXML are not directly usable for local standards as each country have it's own specification. [Add an exemple]

A tool for adjusting an .ifc file to local regulations is BIMxBEM which currently has a configuration to support Swiss standards for energy modeling. Contact the developer and you can start making a new localization.

Scientific article or conference paper on energy modeling[edit]

Full text
available ?
Title Short resume
Yes 2020 IFC to Building Energy Performance Simulation: A systematic review of the main adopted tools and approaches
Yes 2020 IFC-Based BIM-to-BEM Model Transformation
Yes 2017 Automatic generation of second-level space boundary topology from IFCgeometry inputs Polyhedron algorithm
Yes 2017 Template based code generation of Modelica building energy simulation models City to Modelica
Yes 2016 BIM based whole-building energy analysis towards an improved interoperability IFC to gbXML
Yes 2016 BIM enabled building energy modelling: development and verification of a GBXML to IDF conversion method gbXML to idf to design4energy
Yes 2016 Model View Definition for Advanced Building Energy Performance Simulation Energy MVD
Yes 2016 Research & Development Roadmap for BuildingEnergy Modeling
Yes 2015 Service-Oriented Architecture For DataExchange Between A Building InformationModel And A Building Energy
Yes 2015 Link between BIM and energy simulation IFC to Space Bondary Tool to IDF to energy+
gbXML to IDF to energy+
Yes 2014 Translating Building Information Modeling to Building EnergyModeling Using Model View Definition Revit to Modelica
Yes 2013 Transforming BIM to BEM: Generation ofBuilding Geometry for the NASA AmesSustainability Base BIM Ifc to BEM using Space Boundary Tool
Yes 2013 Interfacing BIM with Building Thermal and Daylighting Modeling Revit to Modelica
Yes 2013 A Thermal Simulation Tool for Building and Its Interoperabilitythrough the Building Information Modeling (BIM) Platform State on softwares in 2013
Yes 2011 ThermalOpt: A Methodology forAutomated BIM-BasedMultidisciplinary ThermalSimulation for Use in OptimizationEnvironments Ifc to thermal simulation
Yes 2008 IFC BIM-Based Methodology for Semi-Automated Building EnergyPerformance Simulation Ifc to energy+
No 2015 A process to divide curved walls in IFC-BIM intosegmented straight walls for building energyanalysis Curved wall segmentation
No 2017 Building Information Modelling for analysis of energy efficientindustrial buildings – A case study Revit to gbXML to sketchup to idf to energy+
No 2013 An algorithm to generate space boundaries for building energysimulation Graph algorithm
No 2016 Automation of CAD models to BEM models for performance basedgoal-oriented design methods
No 2016 A framework to integrate object-oriented physical modelling with building information modelling for building thermal simulation
No 2007 A comparative study of the IFC and gbXML informational infrastructures for data exchange in computational design support environments Revit to Modelica
No 2016 BIM IFC information mapping to building energy analysis (BEA) model with manually extended material information
Yes 2019 A combined scientometric and conventional literature review to grasp the entire BIM knowledge and its integration with energy simulation
Yes 2021 Automatic IFC data enrichment with space geometries for Building Energy Performance Simulations
Yes 2021 Automatic generation of second level space boundary geometry from IFC models
Yes 2019 A Workflow for Automated Building Energy Performance Model Generation Using BIM Data
Yes 2019 An IFC data preparation workflow for building energy performance simulation

See also[edit]

External Resources[edit]

This page is about AEC_Free_Software_directory#Analysis_and_Simulation software and the Category:Analysis_and_Simulation. This category currently includes software for Structural Analysis & Environmental Analysis.