topic Re: revit parameter types for ifc export ??? in Revit API Forum

revit parameter types for ifc export ???

pipapongo0909 — Wed, 14 Dec 2016 12:56:33 GMT

hi forum,

i am trying to figure out which revit parameter types are exportable to ifc.
i got the following figured out allready but only for the discipline comon.

this is the structure of the input file for creating propertysets in the IFC

PropertySet: [NameOfThePropertySet] [I]or[T]_for instance or Type [IfClass1],[IfClass2],...
[NameInIFCDatei] [RevitParametertype] [NameOfTheParameterInRevit]

########################################################################################

Revit Parameter Type IFC Parameter Type

-----------------------------------------------------------------
Text                                           Text
Integer                                  Integer
Number                               Real
Length                                   Length
Area                                      Area
Volume                                  Volume
Angle                                     Real
Slope                                       Real
Currency                                 Currency
Mass Density                          MassDensity
URL                                     URL
Material                                  Material
Image                                     Image --> wil export file path
Yes/No                                    Boolean
Multiline Text                           Text

is anybody familiar with the code, i guess there should be some kind of class or switch /if else that determines whats available.

thanks,

Jeff

Re: revit parameter types for ifc export ???

jeremytammik — Thu, 15 Dec 2016 14:35:57 GMT

Dear Jeff,

I cannot say anything at all about this off-hand.

I can pass it on to the development team for you.

First, however, it would be helpful to understand why you are asking this at all.

Can you explain, please?

Thank you!

Cheers,

Jeremy

Re: revit parameter types for ifc export ???

pipapongo0909 — Thu, 15 Dec 2016 21:23:36 GMT

Wow "The Building COder" himself"! awsome 🙂

Well, hi and thanks for the quick reply.

Let me get you a little more context and re-formula my question more precisely, i got the feeling i was a bit fuzzy:

Actually i had troubles myself of getting to know all this and kind of feel this needs to be in the forum since it could help others to get way faster to be able to export a good IFC File from Revit.

I am in the preparations of a project where i will be able to export an IFC-file from Revit and attach several parameters from my projectfile.rvt to the the property sets. I am using the open source "IFC for Revit" - Ifcexporter tool to do so.

I am creatiing an inputfile.txt that makes the IFC exporter to:

create and name propertysets to a specific IFC classes
and define what parameters should be attached to this Property Set ( which in my definition is "the way off non geometric date inside the IFC")

The exporter lets me map my "Revit categories" independantly to "IFC Classes". For this i create the "shared Revit Parameter" named "IfcExportAs" and assign to all of the"exportable category" ( or individual Elements of this "category" by making the parameter instance based )in Revit by giving it either of this values:

"dontExport" for not exporting the element at all ( not even the geometry)
"exportable category" for exporting it to this category

the input file looks this way:

****MISSING

will replace this tomorrow here since i am at home and have no access to it now"

****MISSING END

****MISSING

Explanation of the file

****MISSING END

So here comes the part where is is getting tricky because i have not got it figured out yet entirely:

As you see you have to map the Revit "parameter types" to "IFC Parameter types":

there are some easy ones:

Text Text
Integer Integer
Length Length

Text Text

Currency                                 Currency
Length                                   Length
Area                                      Area
Volume                                  Volume

Currency Currency

URL URL

and some not so obvious ones:
Mass Density MassDensity
Yes/No Boolean

Number                               Real
Angle                                     Real
Slope                                       Real

and the ones i do not have figured out yet what goes to the IFC

Material ?????..... propably the name of the Revit material
Image ????....... Image exports the name of the image

Multiline Text ????.......Text

the list is pretty long list. I think the IFC has even Units included so if you are not interested in the unit you could probably map every number to REAL

****MISSING

i don't find a link but i guess i have a list at the office

****MISSING END

since we will need to export the parameters of the type "Structural" i want to figure out the others as well.

thats what i am asking for and since the code is open source it should be possible to understand ( or even interact with) it do crate more effective IFC files.

Sorry if i am telling you what you certainly already know but this needs to be shared, extually i would love to if people correct me if i am wrong somewhere or even sharing what they know.

So thanks again for showing interest and thanks for the great page http://thebuildingcoder.typepad.com/. i can't whait to get started with the c++ or C# tutorials as soon as i get the time. ( i got some experience with C++ and the Qt framework so actually i am hopping to be able to interact with Revit on a more programmatic level 🙂 )

have a great evening

best regards,

Jeff

Re: revit parameter types for ifc export ???

jeremytammik — Fri, 16 Dec 2016 16:09:25 GMT

Dear Jeff,

Thank you very much for your appreciation.

Glad to hear that you find The Building Coder useful.

Also glad to hear you are working with the open source Revit IFC project.

In that case, I would suggest that you submit your question there and discuss it with those people, who are the real IFC experts:

https://sourceforge.net/p/ifcexporter/discussion

https://sourceforge.net/p/ifcexporter/discussion/general

All I can really do anyway is to forward your question to them.

Discussing it there will be more direct and effective, and also you will be in the middle of a community of peers who will both be more interested, willing and above all able in hearing what your issue is, helping you with it, and discussing the result in depth.

I will be very interested to hear the end result as well.

I hope this helps.

Cheers,

Jeremy

Re: revit parameter types for ifc export ???

pipapongo0909 — Fri, 16 Dec 2016 17:22:48 GMT

Hi jermey,

Thanks for the answer. I will definitely post it there. I keep you updated in this thread so once i will wait until i got my answers and then post the link here before marking the question as solved.

Have a nice w.e.

best regards,

Jeff

Re: revit parameter types for ifc export ???

Anonymous — Mon, 17 Feb 2020 11:13:06 GMT

Hi Jeff and The building Coder,

After 3 years, I found this page. I think I'm trying to do the same thing but a little complex.

I want to automatic the process of creating the PropertySet text file with a user interface.

To avoid typing errors and make it much easier for Revit user.

And when I finished this, we will let it open-sourced and push this to the project IFC for Revit.

Same as you, I need to create the property set with this format.

# User Defined PropertySet Definition File

# Format:

# PropertySet: <Pset Name> I[nstance]/T[ype] <element list separated by ',' [IfcClass]>

# <Property Name 1> <Data type> <[opt] Revit parameter name, if different from IFC>

# <Property Name 2> <Data type> <[opt] Revit parameter name, if different from IFC>

My idea is lanch an analyse of the project opened to get all category of the model, the property groups in each category and properties in each group. Then reform and merge all the data to a treeview of PropertyGroup - Property - Category. then I could fill the table below like this.

# PropertySet: NameOfPropertyGroup I/T <Category to IfcClass>

# NameOfProperty <RevitParameterType to IFCParameterType>

Here is my actual interface. Hope this could help you understand my work.

And now I have met two problems.

1 -- The first one is to get the correct IfcClass form the category/element of Revit API.

I found a method GetIFCClassNameByCategory( ElementId catId, ExporterIFC exporterIFC ) in the API page https://www.revitapidocs.com/2020/7fff2d3a-4175-f2be-4ccc-2f6c5768b38b.htm

But it needs the ExporterIFC class, I couldn't new an instance of this element, but I couldn't find how to get the current ExporterIFC too.

Related page with the same problem in the discussion of SourceForge IFC for Revit.

https://sourceforge.net/p/ifcexporter/discussion/general/thread/dce6bfc7d7/

There are some people doing the mapping of IFC classes their own (using a table of mapping created by themselves).

https://sourceforge.net/p/ifcexporter/discussion/general/thread/4b3bb88d/

https://sourceforge.net/p/ifcexporter/discussion/general/thread/1ee52902/

But I want to it connected with Revit itself, to avoid those potential human errors and different version errors.

So, can you guide me how could I do this mapping or get the current ExporterIFC to use the method directly?

2 -- The second is the problem of parameter type mapping.

from the RevitParameterType to the IFCParameterType.

Did you found the solution in the discussion of SourceForge?

One more thing is, I found a resource ! just maybe, I think it's maybe the same problem with an Autodesk University Class page!

https://sourceforge.net/p/ifcexporter/discussion/general/thread/9113d409/

Unfortunately, it's a 404 Page not found.

So, after all this, I'm turning to you and The Building Coder.

(by the way, I'm a big fan of the blog the-building coder too! it helps me a lot. high five ! )

Have a good day,

Best regards,

Yousheng

Re: revit parameter types for ifc export ???

jeremytammik — Mon, 17 Feb 2020 13:18:40 GMT

Dear Yousheng,

Thank you for the interesting question.

I am not an expert on the Revit IFC functionality.

I suggest that you raise this question in the open source Revit IFC import/export discussion group, where you already found so much valuable information:

https://sourceforge.net/p/ifcexporter/discussion/general

They will be better able to help you.

Best regards

Jeremy