buildingSMART Forums

Question about MVD, IDM, COBie, etc.

Hello,

I have some questions about these formats.
As I understand it, COBie and many others are MVDs (model view definition). The MVD is used with an IFC and an XML file together. The XML file just describes what elements and attributes are displayed like a filter.

What is IDM? As I understand it, its also used like a filter. What is OWL?

Can someone explain me the differences? It seems for me that there are many approaches and I have to chose what I want to use?

I’m just a little bit confused about these many formats.

best regards
Alex

Hi @alex4omnicon, welcome to the Forum!

You could start with reviewing some of the descriptions on the technical website: https://technical.buildingsmart.org/. You can also look at an article recently written for UpFront eZine: https://www.upfrontezine.com/2020/06/upf-1058.html. There may be a lot of info to unpack there, but I think they give good layman explanations of the very things you have question about.

They aren’t all “formats”, but I can see how the acronym soup can be confusing. Simply put, you could look at it this way:

IFC is the schema to describe the built environment in an open, software-agnostic, standardized way. It is not a file format itself, but it is a description/specification that is formatted in a particular way, with the ability to have multiple file formats for actual usage.

An IDM is documentation of one or more processes that rely on data exchange. The IDM specifies the process(es) and the data exchange requirements. It is a precursor, or source, of data exchange requirements that will be translated into an MVD.

An MVD is a specification for a subset of the overall IFC schema, used for a specific data exchange. Ideally, it uses the same form and format as the source IFC schema to describe the data. But, it can also contain additional specific data requirements, like custom properties, or specific values for certain data fields. There is an mvdXML file format that has been recently developed for IFC4 and used to capture an MVD in a “machine-readable” way.

COBie is a data exchange specification like the IFC schema, but also has a corresponding IFC MVD. It also has an IDM describing why the data is important and how it applies to the owner/operator’s business case. In this case, COBie is focused on the data needed to be exchanged from the design and construction process to the owner/operator for facility management purposes.

An IFC file can be formatted in a couple of different ways. The primary one is a STEP Physical File (IFC-SPF), most commonly seen as a *.ifc file. It can also be formatted as an XML file, *.ifcxml, with the same information as the SPF. An IFCZIP file can contain either an SPF or XML format of the model, as well as supplemental files (e.g. images, PDFs, CSV, etc.). Output using any format really depends on the receiving application and its preferred file type.

IfcOWL is another way of accessing information IFC-based model data and linking it with other external data that may not be explicitly described in the IFC schema. It is a commonly used semantic web methodology. There are some applications that have been developed to exploit this method, but it is not a “common” consumer use. Other methods and formats currently being researched and pursued include JSON and HDF5 based versions of IFC-based exchanges and files.

I hope this helps. If you have any more questions, please ask!

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I’m not sure of the best place to mention this but the link to examples of MVDs is dead.

This page:

tries to link to:
https://technical.buildingsmart.org/standards/mvd/mvd-database/

Which gives a 404 error

It is maybe meant to link here?

There’s the start of some basic introductory information about MVDs with @Moult at the https://wiki.osarch.org/index.php?title=Model_View_Definitions_(MVD) page

Please, please, please someone add a link checker to the bS website to find these dead links before people need them - how many people would bother to write … ?

Thanks in advance.

@Duncan_Lithgow All the links should be properly working now.

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Thanks @jwouellette. Is there a reason why there is no link to the documentation for COBie? They are listed in part here: https://wiki.osarch.org/index.php?title=Construction_Operations_Building_Information_Exchange_(COBie)
But It would be better if the OSArch website just pointed to the one page and people find things themselves from there.

@Duncan_Lithgow The COBie documentation is not a bSI standard… yet. It is an MVD based on IFC2x3 and IFC4, but was submitted to the NBIMS-US Version 3 effort. There is currently a proposal to bring COBie 2.5 into the bSI Process and make it a full bSI standard MVD.

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COBie is on COBie.buildingsmart.org and in the MVD database.