Exporting IFC & gbXML for energy simulation

[hijazi]

I would like to inquire about the export functionally of IFC and gbXML data models from Revit for the purpose of energy simulation; 1) Which modules/elements are supported from gbXML/IFC?
If I export IFC & gbXML from the same Revit file,  does the gbXML file have the same exact data (geometry & thermal) that IFC has?

[neko.enko]

Hey hijazi, nice question! I was so interested in it that decided to do my thesis about the topic which is related.

Overall I would say that Revit supports the GbXML scheme better. You have all the thermal properties exported in the GbXML and also you have the better control on the geometry thanks to the preview during the export. GbXML has R-value, conductivity, density and specific heat parameters for the materials layers. As well as U-value, roughness and absorptance for the building element.

While IFC has all the same stuff for the building element, but does not preserve the layer properties. IFC export also results in building elements represented as swept solids or breps, resulting in 6 surfaces, while only one surface is required for the building simulation.

Also Revit has nice connection to Energy plus, which allows you to preserve all the materials properties for the simulation (in case you are using it)

Hope it helps.

[arghavan.A]

Hi @neko.enko

May I ask what do you mean by "Also Revit has nice connection to Energy plus, which allows you to preserve all the materials properties for the simulation (in case you are using it)"? What do you mean by nice connection? 

And can you please explain "While IFC has all the same stuff for the building element, but does not preserve the layer properties. IFC export also results in building elements represented as swept solids or breps, resulting in 6 surfaces, while only one surface is required for the building simulation."

Thank you!

Arghavan

[neko.enko]

Hi Arghavan!

I am glad that my post still stirrs the interest in the community, but infortunatelly I did not engage in BIM pretty much since 2015 and I would not be able to answer your questions.. The full text of my thesis is available online at the academia.edu, or at the library of the TU Wien, so if you are interested you can have a look yourself, the text is in English.

https://www.academia.edu/28655845/Full_Master_Thesis_Framework_for_the_transfer_of_building_material...

If you do not find the answer to your question there, feel free to drop me a line and I will try to dig out my findings again.

Please note that the software might have changed a lot since the time of my research.

Best,

Anna.

[arghavan.A]

Thank you! I will read your thesis 🙂