Exporting gbxml

[Anonymous]

I had posted this as a second question before and no one responded to it so I try once more:

2. When you are exporting as a gbXML file I think that Revit is creating the interior walls as well as the exterior walls, is there a way to choose which walls or information can be exported?
The reason for this is that Carriers HAP program can only have so many wall inputs (eight I think) and when I exported the gbXML file and then imported it into HAP I got an error message (not critical) that said that there were too many walls being imported for each space. Any help please? (It was only not critical in the sense that the program still ran however the program does need to know the outside walls for correct calculations.)

[Anonymous]

I am having the same problem with Trane's Trace 700 load calculation software. Having additional walls increases the exterior surface area of the room, which in turn, increases heat transfer. Have you tried clicking on the wall --> Properties --> Edit/New --> change Wall Function to Interior? That did not solve the problem on with Trane's software, but it might for Carrier's. Take a look at the attached .JPG that describes what I have written. Do you know how to change the 'Assembly Description' from Exterior to Interior?

[KyleB_Autodesk]

Hey guys,
Good discussion, I figured I'd chime in with some info on the subject.

The settings here are really not controlled by the program, but rather the gbXML schema itself. By definition, a space (or Room in Revit terms) is deemed "Interior" if it has other spaces adjacent to it. A wall will be deemed interior if there's a space on both sides of it. The Parameter in the Wall type has no bearing on the gbXML export.

I've done a test myself this morning and I got expected results in Trace 700. The walls in the interior rooms didn't even show up in Trace, as desired.

Does that clear things up for you guys?

Kyle B
Autodesk Support

[Anonymous]

Have you tried it with Carrier? My company uses their HAP program and I was just using the tutorial. And when I exported it and then imported it into HAP it said I had too many walls per space.

[Anonymous]

HAP permits up to 8 exterior wall surfaces per space. The gbXML schema permits an unlimited number of exterior wall surfaces. When HAP is importing gbXML, if it finds more than 8 exterior wall surfaces associated with a space, it imports the first 8 and then must discard the remainder. But it will record the fact that some wall surfaces had to be discarded and will inform the user about this on the Translation Report.

Please note that explanations of each error message on the Translation Report is found in the HAP on-line help system this may help in troubleshooting this error condition and any others that you may encounters. For example, in this case the Translation Report will note that this is an "Error 707 - More than 8 Exterior Wall Surfaces Exist for this Space". Go into the Help system, use the Find tab to search for the ketyword "707" and you will find the following explanation. Or if you go to section 31.5 in the help system you'll find a collection of all of these error descriptions for gbXML import.

Error 707 - More than 8 Exterior Wall Surfaces Exist for this Space

Description: This problem occurs when a space in gbXML has more than eight exterior wall surfaces. HAP limits a space to a maximum of eight exterior wall surfaces. Therefore, data for the first eight wall surfaces can be imported, but data for additional wall surfaces must be discarded. For this error item, the "Value" column lists the ID for the wall surface in gbXML that was discarded. An error item will be generated for each surface that is discarded so that each surface ID can be reported.

Note: The limit of eight exterior wall surfaces only applies to above grade walls. Below grade basement walls are not affected by this limit.

Suggested Action: After gbXML data has been imported, revise space data to account for the discarded data. One strategy is to combine the areas of discarded surfaces with the eight surfaces already included in the HAP data. Another strategy is to divide the space into multiple parts, each with eight wall surfaces, until all surfaces have been included. Note: If you anticipate importing gbXML again for this project as floor plan drawings change, you should not split the space into multiple parts. The "Replace Existing" feature used when updating HAP data with gbXML from revised drawings depends on being able to match gbXML and HAP spaces. Splitting a space into multiple parts will prevent this matching.

Regards,
Brian Key, P.E.
Manager - Software Training and Support
Carrier Corporation
Bynum Training Center - Software Systems Network
Technical Support: 800-253-1794
software.systems@carrier.utc.com

[Anonymous]

Information about interior wall surfaces should not contribute to this issue.

HAP only looks at the exterior wall surfaces when translating exterior walls. We understand Revit contains descriptions about all surfaces in a room - whether exterior or interior walls, floors, ceilings, roofs, etc. This information is written into the gbXML file which is OK. When HAP is importing the data it is able to differentiate between exterior and interior walls. So, it is OK that Revit is exporting interior wall data.

One thing we have seen in the past is that a single wall surface with one orientation (south for example) is sometimes subdivided into many parts by other CAD or BIM systems. This behavior could contribute to the "more than 8 wall surfaces" issue. One approach to overcome the issue is to look at the space that contributing to this problem. In a physical sense, how many exterior walls should the space have? If the answer is 8 or less, you should be OK. But if you are getting the HAP Error 707 for this space, that suggests that Revit has subdivided the exterior walls so that there are more than 8 total exterior wall surfaces. How to suppress that subdividing behavior is a question that remains.

Example: You know a space has only South and East exterior wall exposures so it should have 2 exterior wall surfaces. But suppose for some reason the program internally subdivided these into 5 south oriented surfaces and 6 east oriented surfaces for a total of 11. When importing this data, HAP will import the first 8 and discard the last 3.

We hope this helps.

Regards,
Brian Key, P.E.
Manager - Software Training and Support
Carrier Corporation
Bynum Training Center - Software Systems Network
Technical Support: 800-253-1794
software.systems@carrier.utc.com

[KyleB_Autodesk]

Great Info Brian, thanks for chiming in on the subject. Btw, say hello to John Hall and Bob Fedeuk for me at Bynum.

Cheers,
Kyle B
Revit Systems Product Manager

[Anonymous]

This does not really clear things up for me. I am new to Revit and want to export to GBXML for Trace 700. I have received the architectural files for two different projects from two different architects. On one, no room names or numbers were imported in and rooms had exterior loads and roof loads when the were in the middle of the building. The other one imported room numbers but every wall was an exterior wall and sizes and lengths of the walls made no sense at all. I am assuming that if the architects don't draw it correctly, my exported file is basically useless. Is there a step i am missing or am i receiving files that were not created correctly? I have followed all of the tutorials.

tim

[Anonymous]

I am currently having the same problem, and I am now wondering if it was created correctly by the arch. After reading your post, the excessive number of walls may be due to the multiple families being used. You are correct it seems that all interior walls are being ignored. Could you enlighten me to the wall naming methods used by revit? They seem to be based on orientation and room name?

[KyleB_Autodesk]

What does the analytical model look like in the Heating and Cooling Loads dialog? A shaded view within the dialog is a great troubleshooting tool for getting a nice output.

Cheers,
Kyle B
Revit MEP Product Manager

[Anonymous]

Sorry for bumping the thread, but i am encountring a problem while exporting the gbxml file to Carrier HAP.

I am not able to import the partition (interior) wall data ( i only need the partition wall area) into HAP from GBXML, except that i am able to get all other data like space area, height, lighting load, equipment load, occopancy, exposed wall orientation and area with window area, etc,.

FYI, i am exporting GBXML from revit, taking spaces as export category (even though it not going to make any difference)

[projetos7RKLZ]

Did you figure out how to get info on partitions? I'm looking for it everywhere and can't find how to do it.