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Problems converting gbXML to IDf

asked 2016-06-13 10:42:08 -0500

Om's avatar

updated 2016-06-13 12:44:05 -0500


I am exploring a workflow that involves exporting a gbXML file from a Revit model and converting the gbMXL file to an IDF file via OpenSudio. I encounter an empty required field problem that cause errors when running an EmergyPlus simulation using the converted IDF file.

I came across a forum post related to this problem and tried to follow the discussion; however, I still cannot find a solution. Here is the post: In the discussion, I acknowledge that it's a known bug and has been solved in the late versions on OpenStudio. Furthermore, the conversation seems to focus on window problems. I basically encounter problems with the building shells (e.g., floors, wall, and roof), as well.

Regarding my workflow, I installed OpenStudio 1.11.5 which exports EnergyPlus 8.5. I imported a gbXML file via the OpenStudio extension installed inside SketchUp 2016. I exported an IDF file. I examined the IDF file via a text editing tool and found that the values for the 'Construction Name' fields are empty (please see an example below), which causes errors when running the simulation.

  aim0149,                                !- Name
  Wall,                                   !- Surface Type
  ,                                       !- Construction Name
  aim0024 ThermalZone,                    !- Zone Name

Could anyone please share your insights regarding how to overcome this issue? I am very open to less-manual-editing ideas whether the issue should be solved in Revit, SketchUp, OpenStudio, IDFEditor, or other third-party software.

Thank you very much.

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As far as I'm concerned, current release of OS does not read Constructions from gbXML files, as well as loads and even elements names (as you see it uses IDs instead). But NREL announced some months ago that they are going to make OS first software certified against working with gbXML schema. Look forward as I use Revit to create models too. So, the only way is to add constructions manually, but when you don't know what surface where... that's almost impossible...

Dinosaver's avatar Dinosaver  ( 2016-06-13 14:04:33 -0500 )edit

Dinosaver, Thank you very much for sharing your insight. In a small test model, I was able to inspect the surfaces and manually assigned the construction names (actually ids). However, when it comes to the real project that I have to do the conversion, I agree that it seems almost impossible. I tried to create an instance of the OS:DefaultConstructionSet object and assigned it to a space. This helped remove errors quicker than assigning a construction to each surface; however, do you think this approach would work for a big multiple-space project?

Om's avatar Om  ( 2016-06-13 15:36:40 -0500 )edit

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answered 2016-06-14 11:42:18 -0500

updated 2016-06-14 12:34:47 -0500

Here is a link to our current gbXML import/export. @macumber is on vacation but when he gets back I can follow up with him about the plans for gbXML schema certification.

gbXML import (geometry, constructions, thermal zones, and schedules only)
gbXML export (geometry, constructions, and thermal zones only)

Constructions should be supported, but there may be an issue related to that. If you have a sample gbXML file with constructions please send it to and we can use it internally for testing.

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David, Thank you for the information. I just learned that I should use the analysis space object to define spaces in the Revit model instead of the room object. By using this method, the construction references will be associated with surfaces. However, I still have a problem with window references.

----Exported .idf---- FenestrationSurface:Detailed, aim0316, !- Name Window, !- Surface Type , !- Construction Name


Om's avatar Om  ( 2016-06-14 15:37:31 -0500 )edit

(2/2) I recognize the differences between a gbXML-to-IDF-Test-Cases and the gbMXL file exported from Revit as follows:

----gbXML-to-IDF-Test-Cases---- <opening interiorshadetype="Operable" exteriorshadetype="Fixed" windowtypeidref="PwindowType-158" openingtype="FixedWindow" id="aim39844"> ----Revit exported gbXML---- <opening windowtypeidref="aim0141" openingtype="OperableWindow" id="aim0184">

Could you please recommend how to model windows in Revit?

Om's avatar Om  ( 2016-06-14 15:44:11 -0500 )edit

I just checked and it appears that OpenStudio does not translate the windowtype elements from gbXML to OS. Also, I thought that OpenStudio exported constructions but it does not appear to.

macumber's avatar macumber  ( 2016-06-20 15:56:12 -0500 )edit

@Om I have the similar problem with windows that I modeled in Revit and exported as gbXML and imported to OS. I wanted to know if your problem is solved, or if you have found any solution to fix it?

Arghavan.A's avatar Arghavan.A  ( 2017-11-14 15:30:51 -0500 )edit

@macumber May I ask for a reference for your statement? I want to include it in my report.

Arghavan.A's avatar Arghavan.A  ( 2017-11-14 15:34:01 -0500 )edit

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Asked: 2016-06-13 10:42:08 -0500

Seen: 1,562 times

Last updated: Jun 14 '16