Editing Building Energy Modeling (BEM)

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=Introduction=
There is currently 2 BIM format related to energy modeling : [https://www.gbxml.org/ gbXML] and IFC ([https://standards.buildingsmart.org/IFC/RELEASE/IFC4_1/FINAL/HTML/link/ifcrelspaceboundary2ndlevel.htm 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 [https://vimeo.com/539127482 BR5 - Jeffrey Ouellette - Building Energy Modelling (BEM)].

Note to editors: Add a gbXML vs IFC features comparison

=Energy modeling workflow (/!\Work in progress/!\)=
==Modeling the building==
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.

==FOSS authoring tools==
'''BlenderBIM Add-on'''
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==
An algorithm need to generate energy specific [https://standards.buildingsmart.org/IFC/RELEASE/IFC4_1/FINAL/HTML/link/ifcrelspaceboundary2ndlevel.htm space boundaries]
==Export to common energy exchange formats==
Software need provide an Ifc or gbXML.

=== Revit ===
==== Configuration ====
TODO
==== Known issues ====
{{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

=== ArchiCAD ===
==== Configuration ====
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 ====
{{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==
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=

{| class="wikitable sortable" style="text-align:center;"
|-
! Full text<br />available ?
! publication<br />year
! style="text-align:left;" | Title
! style="text-align:left;" | Short resume
|-
| Yes
| 2020
| style="text-align:left;" | [https://www.researchgate.net/publication/345983333_IFC_to_Building_Energy_Performance_Simulation_A_systematic_review_of_the_main_adopted_tools_and_approaches IFC to Building Energy Performance Simulation: A systematic review of the main adopted tools and approaches]
| style="text-align:left;" | 
|-
| Yes
| 2020
| style="text-align:left;" | [https://www.researchgate.net/publication/341025570_IFC-Based_BIM-to-BEM_Model_Transformation IFC-Based BIM-to-BEM Model Transformation]
| style="text-align:left;" | 
|-
| Yes
| 2017
| style="text-align:left;" | [https://discovery.ucl.ac.uk/id/eprint/1546334/1/CBIP_revised.pdf Automatic generation of second-level space boundary topology from IFCgeometry inputs]
| style="text-align:left;" | Polyhedron algorithm
|-
| Yes
| 2017
| style="text-align:left;" | [https://www.researchgate.net/publication/318218730_Template_based_code_generation_of_Modelica_building_energy_simulation_models Template based code generation of Modelica building energy simulation models]
| style="text-align:left;" | City to [[Modelica]]
|-
| Yes
| 2016
| style="text-align:left;" | [https://www.ofcoursecme.nl/?mdocs-file=3201 BIM based whole-building energy analysis towards an improved interoperability]
| style="text-align:left;" | IFC to gbXML
|-
| Yes
| 2016
| style="text-align:left;" | [https://repository.lboro.ac.uk/articles/BIM_enabled_building_energy_modelling_development_and_verification_of_a_GBXML_to_IDF_conversion_method/9437450 BIM enabled building energy modelling: development and verification of a GBXML to IDF conversion method]
| style="text-align:left;" | gbXML to idf to design4energy
|-
| Yes
| 2016
| style="text-align:left;" | [https://www.researchgate.net/publication/308614558_Model_View_Definition_for_Advanced_Building_Energy_Performance_Simulation Model View Definition for Advanced Building Energy Performance Simulation]
| style="text-align:left;" | Energy MVD
|-
| Yes
| 2016
| style="text-align:left;" | [https://www.energy.gov/sites/prod/files/2016/02/f29/DOE-BTO-BEM-Roadmap-DRAFT-2-1-2016.pdf Research & Development Roadmap for BuildingEnergy Modeling]
| style="text-align:left;" | 
|-
| Yes
| 2015
| style="text-align:left;" | [https://www.researchgate.net/publication/279198228_Service-Oriented_Architecture_For_Data_Exchange_Between_A_Building_Information_Model_And_A_Building_Energy_Model Service-Oriented Architecture For DataExchange Between A Building InformationModel And A Building Energy]
| style="text-align:left;" | 
|-
| Yes
| 2015
| style="text-align:left;" | [https://www.researchgate.net/publication/300634003_Link_between_BIM_and_energy_simulation Link between BIM and energy simulation]
| style="text-align:left;" | IFC to Space Bondary Tool to IDF to energy+<br />gbXML to IDF to energy+
|-
| Yes
| 2015
| style="text-align:left;" | [https://www.researchgate.net/publication/282814185_INTEROPERABILITY_OF_BUILDING_ENERGY_MODELING_BEM_WITH_BUILDING_INFORMATION_MODELING_BIM INTEROPERABILITY OF BUILDING ENERGY MODELING (BEM) WITH BUILDING INFORMATION MODELING (BIM)]
| style="text-align:left;" | 
|-
| Yes
| 2014
| style="text-align:left;" | [https://www.researchgate.net/publication/266951250_Translating_Building_Information_Modeling_to_Building_Energy_Modeling_Using_Model_View_Definition Translating Building Information Modeling to Building EnergyModeling Using Model View Definition]
| style="text-align:left;" | [[Revit]] to [[Modelica]]
|-
| Yes
| 2013
| style="text-align:left;" | [https://simulationresearch.lbl.gov/sites/all/files/lbnl-6033e.pdf Transforming BIM to BEM: Generation ofBuilding Geometry for the NASA AmesSustainability Base BIM]
| style="text-align:left;" | Ifc to BEM using Space Boundary Tool
|-
| Yes
| 2013
| style="text-align:left;" | [https://www.researchgate.net/publication/262009985_Interfacing_BIM_with_Building_Thermal_and_Daylighting_Modeling Interfacing BIM with Building Thermal and Daylighting Modeling]
| style="text-align:left;" | [[Revit]] to [[Modelica]]
|-
| Yes
| 2013
| style="text-align:left;" | [https://www.mdpi.com/2075-5309/3/2/380/pdf A Thermal Simulation Tool for Building and Its Interoperabilitythrough the Building Information Modeling (BIM) Platform]
| style="text-align:left;" | State on softwares in 2013
|-
| Yes
| 2011
| style="text-align:left;" | [https://www.researchgate.net/publication/257778673_ThermalOpt_A_methodology_for_automated_BIM-based_multidisciplinary_thermal_simulation_for_use_in_optimization_environments ThermalOpt: A Methodology forAutomated BIM-BasedMultidisciplinary ThermalSimulation for Use in OptimizationEnvironments]
| style="text-align:left;" | Ifc to thermal simulation
|-
| Yes
| 2008
| style="text-align:left;" | [https://eetd.lbl.gov/sites/all/files/publications/919e.pdf IFC BIM-Based Methodology for Semi-Automated Building EnergyPerformance Simulation]
| style="text-align:left;" | Ifc to energy+
|-
| No
| 2015
| style="text-align:left;" | [https://www.researchgate.net/publication/282533267_A_process_to_divide_curved_walls_in_IFC-BIM_into_segmented_straight_walls_for_building_energy_analysis A process to divide curved walls in IFC-BIM intosegmented straight walls for building energyanalysis]
| style="text-align:left;" | Curved wall segmentation
|-
| No
| 2017
| style="text-align:left;" | [https://www.sciencedirect.com/science/article/abs/pii/S1364032116002173 Building Information Modelling for analysis of energy efficientindustrial buildings – A case study]
| style="text-align:left;" | [[Revit]] to gbXML to sketchup to idf to energy+
|-
| No
| 2013
| style="text-align:left;" | [https://www.researchgate.net/publication/259633402_An_Algorithm_to_generate_space_boundaries_for_building_energy_simulation An algorithm to generate space boundaries for building energysimulation]
| style="text-align:left;" | Graph algorithm
|-
| No
| 2016
| style="text-align:left;" | [https://www.sciencedirect.com/science/article/abs/pii/S0360132316304140 Automation of CAD models to BEM models for performance basedgoal-oriented design methods]
| style="text-align:left;" | 
|-
| No
| 2016
| style="text-align:left;" | [https://www.researchgate.net/publication/271824420_A_framework_to_integrate_object-oriented_physical_modelling_with_building_information_modelling_for_building_thermal_simulation A framework to integrate object-oriented physical modelling with building information modelling for building thermal simulation]
| style="text-align:left;" | 
|-
| No
| 2007
| style="text-align:left;" | [https://www.researchgate.net/publication/285494452_A_comparative_study_of_the_IFC_and_gbXML_informational_infrastructures_for_data_exchange_in_computational_design_support_environments A comparative study of the IFC and gbXML informational infrastructures for data exchange in computational design support environments]
| style="text-align:left;" | [[Revit]] to [[Modelica]]
|-
| No
| 2016
| style="text-align:left;" | [https://www.researchgate.net/publication/303179536_BIM_IFC_information_mapping_to_building_energy_analysis_BEA_model_with_manually_extended_material_information BIM IFC information mapping to building energy analysis (BEA) model with manually extended material information]
| style="text-align:left;" | 
|-
| Yes
| 2019
| style="text-align:left;" | [https://www.researchgate.net/publication/329954730_A_combined_scientometric_and_conventional_literature_review_to_grasp_the_entire_BIM_knowledge_and_its_integration_with_energy_simulation A combined scientometric and conventional literature review to grasp the entire BIM knowledge and its integration with energy simulation]
| style="text-align:left;" |
|-
| Yes
| 2021
| style="text-align:left;" | [https://www.conftool.pro/bs2021/index.php/30888_Lilis_Georgios_Nektarios.pdf?page=downloadPaper&filename=30888_Lilis_Georgios_Nektarios.pdf&form_id=30888 Automatic IFC data enrichment with space geometries for Building Energy Performance Simulations]
| style="text-align:left;" |
|-
| Yes
| 2021
| style="text-align:left;" | [https://www.conftool.pro/bs2021/index.php/30156_Fichter_Eric.pdf?page=downloadPaper&filename=30156_Fichter_Eric.pdf&form_id=30156 Automatic generation of second level space boundary geometry from IFC models]
| style="text-align:left;" |
|}

=See also=
* There is a discussion tag on our forum for [https://community.osarch.org/discussions/tagged/Building_Energy_Modeling_BEM Building Energy Modeling (BEM)]

[[Category:Autodesk Revit]]
[[Category:Building Energy Modeling (BEM)]]
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