IFC Export and Import

[cadsindia]

Hi,

1) When I try to import a column from an IFC file (The IFC file is created in Revit), the column is not imported as Strcutural column.

    Is it possible to import the columns it as a Structural column?

2) When I try to export structural rebar in IFC Format, the ifc file has the info about shape and dimension. But the dimensions of rebar (B/C/D values) are in feet but all other dimensions are seems to be in mm. And moreover when I import the ifc file in Revit, the reinforcment is not imported as rebar(File attached).Could you please clarify?

3) Do you have any plans to export/import analytical memebrs to and from IFC?

Thanks and regards

[Joe.Ye]

For the first question, the structural column imported via IFC to Revit is still structural column. Please change the view setting to see their analytical model.

#2. I imported your ifc file to Revit d2014. And found 2 rebars were sucessfully imported.

#3 I think Revit 2014 can do this.

[cadsindia]

Thanks Joe.

1) Yes. The analytical columns are imported. But the analytical beams are not imported. Refer the snap shots.

2) The rebars are imported into Revit. Butnoe of the rebar properties are imported except the name. After import, we could not use it as rebar.

3) We tried export the analytical member in Revit Strcutures 2014, but the analytical lines are not exported.

Could you please send some sample IFC files  (generated from Revit) with analytical line for members?

Thanks in advance,

Regards,

[cadsindia]

Joe,

I tried to import a frame into Revit using an IFC file (This file is created in another application), the columns in the frame are imported as Architectural columns. But this was not the case when I export the strcutural column from Revit and import it back to Revit.

How can I import the columnsas structural columns (If the IFC file is created by other applications)? 

Thanks in advance.

Regards

[Joe.Ye]

Hello,

#1.Yes, I can reproduce this issue that beam's analytical model is not imported.

#2. I used your file, and opened it in Revit. Found the imported rebar graphics. However, it is an in-place family instance.. This is not a real rebar.
#3. After I tested, and found that the beam's analytical model cannot be imported. Howevel column's analytical can be imported.

Thank for telling us this. I will log a request for your report.

[cadsindia]

Joe,

Thanks for your reply.

Could you please try to import the attached file in Revit. The columns in this file are imported as Columns and not as Strcutural columns. This ifc file is created in another application (Scia Engineer). Could you please help me to import it as Strutural column in Revit?

And may I know when shall we expect the other fixes (Point 1&2 described in the previous reply)?

Thanks in advance.

Regards,

[Joe.Ye]

Hi

It seems that the columns in these two files are not structural columns. After imported to Revit, it looks like architecture column.

Sorry that we don't have the information when they can be fixed.

[afg759]

I'm testing problem issue 1 in revt 2015, and the problem is not fixed yet. 

If a beam element is exported and import from/to RVT 2015, analytical mode of this element is not imported.

Do you have any information about when this problem will be fixed?

Thanks AAFF

[jeremytammik]

Dear Aaff,

Thank you for checking.

I am jumping in for Joe and am a bit confused by the discussion and the different issues listed above.

Could you please provide a clear reproducible case demonstrating exactly what problem you are facing?

http://thebuildingcoder.typepad.com/blog/about-the-author.html#1b

Then I can check that independently with the development team.

In fact, it might even be best if you start a completely new thread for this as a separate topic.

Thank you!

Best regards,

Jeremy

[afg759]

Dear Jeremy,

The problem is that the analitical model of the beam is lost when you export the file to IFC, and import it again.

I´m attatching you the file in RVT and IFC formats, also with two images.

Thanks in advance.

[jeremytammik]

Dear Aaff,

Thank you for providing a reproducible case.

I logged the issue REVIT-42476 [analytical model of rst beam is lost by IFC export + import] with our development team for this on your behalf as it requires further exploration. Please make a note of this number for future reference.

Thank you!

Best regards,

Jeremy

[jeremytammik]

Dear Aaff,

I discussed your issue REVIT-42476 [analytical model of rst beam is lost by IFC export + import] with the Revit development team.

They say:

This is working as expected. Analytical Model is not currently carried in either IFC export or import.

For export, it is an open request on the open source IFC export project:

http://sourceforge.net/projects/ifcexporter

If the developer is interested in enhancing this, it would certainly be welcome.

For import, creation of analytical model should be automatic on IFC open if the beam/member could be imported as a standard structural member, but it will not be carried in other members which have to be translated to in-place families. So an imported IFC would not be suitable for structural analysis without some intervention.

What is the developer hoping to accomplish?

E.g. why export a Revit model to IFC and reimport it back to Revit?

The issue is now closed with a resolution 'Works As Expected'.

Looking forward to your response on this.

Thank you!

Best regards,

Jeremy

[GeomGym]

There is a couple of options.  As you're posting to the API forum, the importer and exporter are open source so you could implement improvments to the code (if you have the time and energy).

If you're willing to consider a 3rd party solution, then I believe my tools could help.

I've been working on IFC export for Revit, primarily for the purpose of extracting the structural analysis model in Revit (but also starting on other aspects such as MEP). http://geometrygym.blogspot.com.au/search/label/Revit  I do generate the "Structural Analysis Model View" classes from the data in the Revit project.

I'm primarily using IFC4 (it has improvements such as cardinal points, load case combinations and applied loading) but it is possible to also use IFC2x3.

I've just tested a similar case to yours with fairly good results.  Is it round tripping you wish to achieve (or is it to get the model into other structural analysis software).  I still need to implement more improvements for aspects such as profile identification (at the moment it helps if you are using catalogue profiles with specific naming convention), or physical member clipping/miters.  But you will get a reasonable round trip already and I am willing to implement specific improvements if critical issues are identified.

I've attached the resulting IFC4 file from my tools.  

Let me know if you want to test and I'll advise further.

Cheers,

Jon

[TeunHam]

---

@Anonymous wrote:

...

What is the developer hoping to accomplish?

E.g. why export a Revit model to IFC and reimport it back to Revit?

The issue is now closed with a resolution 'Works As Expected'.

Looking forward to your response on this.

Thank you!

Best regards,

Jeremy

---

Warning: People without any sense of humor should not read anything below this line!

-----------------------------------------

Why would we export something to IFC and import it back into Revit? Is that a serious question? Sometimes I wonder if all Autodesk employees are wearing blinkers...

Imagine that NOT everybody on the entire earth is working with Revit...I know, that's hard to believe if you work at Autodesk, but just try to image that not everybody is working with Revit.

Ok, got it? Nice!

On this planet, there's a concept called BIM. Building Information Model. It's a smart way to work together. Sounds great? It is! But there's a problem...not everybody is working with the same CAD system. So how do we interchange information? The answer is IFC (Industry Foundation Classes), an open standard which can be used by everybody on the whole planet to interchange information. Not only the 3D aspect, but also meta data.

Are you still hanging on? Great!

Now here's a funny story...If I am about to send an IFC to somebody else, I want to make sure that the IFC I have created is 100% correct. Is all the data present? Is all the 3D information present? I don't want to receive an IFC from somebody else, only to notice that the IFC is missing crucial bits of information. I also don't want to send an IFC which is not perfect.

So what do I do? I export my model to IFC, start a new Revit Project and import that IFC, just to check if everyting is OK!

That's why I want to export a Revit model to IFC and reimport it back to Revit

Hidden message to Autodesk: take your blinkers off!

[mikako_harada]

Very interesting.  Thank you for sharing, Jon!

[mikako_harada]

Hello, 

I understand your frustration. But we can assure you that Autodesk is putting a lot of effort on IFC. The team who is working on IFC is continuously making updates and making available the updated version through our Exchange Store. They are also available as open source.  In fact, we interacte with them reularly with the store end.  The support that the IFC team is providing to the customers who have been using IFC apps and giving us feedback is one of the best among publishers we can see.  There is also a danger of misleading when we take certain discussion out of context. For example, a change request against the scope of released feature vs. wishes to enhance for future release are tracked differently in our database.  For that part, it was probably our miscommunication to blame. Sorry about it.

As to the use scenario, using reimport for debugging purpose is reasonable as a programmer. Personally, I occasionally use AutoCAD Architecture or the tool like http://www.iai.fzk.de/www-extern/index.php?id=2315&L=1 for testing purpose. That said, we would be still interested in and would be helpful if we can get use case feedback with in practical application, ideally with the data with exchange with other software.  We can certainly have an enhancement wish. 

Back to the analytical model information, at a moment we support IFC2x3 coordination view (1.0 and 2.0). According to the engineer who has been dedicated to IFC work here, in those views, it is disallowed to include analytical model information as part of the IFC file.  As Jon kindly pointed out, IFC have the entities for analytical support and structural analysis view, that would exchange analytical information. Unfortunately, we don’t support it at a moment.  But it is often requested feature and would like to consider as future enhancement. In a mean time, we are glad to see that Jon has worked on this already.  (Impressive job, Jon, by the way.)