Unable to export rebars to IFC

A forum dedicated to the Arch module development
User avatar
cnirbhay
Posts: 83
Joined: Wed Aug 17, 2016 4:24 pm

Unable to export rebars to IFC

Postby cnirbhay » Sat Jan 28, 2017 4:33 am

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.9762 (Git)
Build type: Release
Branch: master
Hash: 0afb7b6a32da8fd4e524bff59172d864e2d1cf8a
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.0.0

I'm unable to export rebars to IFC. Kindly check the file in the attachment.

Thank you.
Attachments
zzzzz.FCStd
(13.09 KiB) Downloaded 4 times
User avatar
bernd
Posts: 3869
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: Unable to export rebars to IFC

Postby bernd » Mon Jan 30, 2017 10:46 am

As far as I know export of rebars to IfcReinforcingBar into IFC has never really been working at all.

Bernd
User avatar
yorik
Site Admin
Posts: 8553
Joined: Tue Feb 17, 2009 9:16 pm
Location: São Paulo, Brazil
Contact:

Re: Unable to export rebars to IFC

Postby yorik » Mon Jan 30, 2017 12:08 pm

As of yesterday, it's now working!
User avatar
Kunda1
Posts: 621
Joined: Thu Jan 05, 2017 9:03 pm

Re: Unable to export rebars to IFC

Postby Kunda1 » Mon Jan 30, 2017 1:23 pm

User avatar
cnirbhay
Posts: 83
Joined: Wed Aug 17, 2016 4:24 pm

Re: Unable to export rebars to IFC

Postby cnirbhay » Tue Jan 31, 2017 5:40 am

yorik wrote:As of yesterday, it's now working!


Ya, its working. I could see the information in Solibri Model Viewer. But it does not indicate diameter or radius there, it just tells bounding box height which can be considered equal to diameter. However, in case of IFC file from Revit, it shows radius under profile section.

Also, when I view the IFC file of FreeCAD in text, I can't see the diameter/radius information there. Moreover, when opened these IFC files in FreeCAD, their diameter info is not shown the data properties.

Kindly view this FreeCAD file
rebar.FCStd
(11.33 KiB) Downloaded 4 times
and its IFC file
rebar from freecad.ifc
(6.91 KiB) Downloaded 4 times
. And also view this IFC file from Revit
rebar from revit.ifc
(12.54 KiB) Downloaded 4 times
of a similar model.

Thank you.
User avatar
yorik
Site Admin
Posts: 8553
Joined: Tue Feb 17, 2009 9:16 pm
Location: São Paulo, Brazil
Contact:

Re: Unable to export rebars to IFC

Postby yorik » Tue Jan 31, 2017 9:01 pm

Can you tell me what exactly is missing in the IFC file?
User avatar
cnirbhay
Posts: 83
Joined: Wed Aug 17, 2016 4:24 pm

Re: Unable to export rebars to IFC

Postby cnirbhay » Thu Feb 02, 2017 10:04 am

yorik wrote:Can you tell me what exactly is missing in the IFC file?


By doing some exploration in the IFC text file of FreeCAD, I could find radius information by somehow. However, there is some comparative analysis that I'm sharing with you.

I'm attaching some screenshots with red marks to be noticed as following:

1. Screenshots of IFC file viewed in Solibri made from Revit:

(a) In this first screenshot, we can see details like bar length and nominal diameter under IFC Dimensions properties.

Screenshot (230)_LI.jpg
Screenshot (230)_LI.jpg (435.79 KiB) Viewed 221 times


(b) In this screenshot, we can see details like type of the profile and radius under profile properties.

Screenshot (231)_LI.jpg
Screenshot (231)_LI.jpg (416.15 KiB) Viewed 221 times


2. Screenshots of IFC file viewed in Solibri made from FreeCAD:

(a) In this screenshot, we can not see any details under IFC Dimensions properties.

Screenshot (232)_LI.jpg
Screenshot (232)_LI.jpg (378.91 KiB) Viewed 221 times


(b) In this screenshot, we can see bounding box details under quantities properties but there are no profile properties as were there for Revit IFC file.

Screenshot (233)_LI.jpg
Screenshot (233)_LI.jpg (410.68 KiB) Viewed 221 times
User avatar
amrit3701
Posts: 21
Joined: Mon Jun 13, 2016 5:37 pm

Re: Unable to export rebars to IFC

Postby amrit3701 » Thu Feb 02, 2017 10:22 am

yorik wrote:As of yesterday, it's now working!


Yes, it is working now. But the facts shared by @cnirbhay in the above screenshots are also something to be considered.

Now, we would like to know the mechanism that you follow to implement FreeCAD model details into IFC.

Can you please share with us the particular guidelines that one needs to follow in order to transfer the desired details into IFC? So that we can also do some workout with FreeCAD code and IFC to contribute a bit in this direction. :)

--
Amritpal Singh
https://www.amritpals.com
https://github.com/amrit3701
User avatar
bernd
Posts: 3869
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: Unable to export rebars to IFC

Postby bernd » Thu Feb 02, 2017 12:27 pm

amrit3701 wrote:Can you please share with us the particular guidelines that one needs to follow in order to transfer the desired details into IFC?
Very interesting question. If you would compare an IFC from ArchiCAD, Allplan, VectorWorks and Revit they all have different attributes and do save them different. Difficault to find what best fits ...

May be we should wait on Yoriks FreeCAD property of typ IFC property. Then we could transfer any FreeCAD property to an IFC property and the IFC exporter just exports the FreeCAD property IFC property data ?!?
User avatar
yorik
Site Admin
Posts: 8553
Joined: Tue Feb 17, 2009 9:16 pm
Location: São Paulo, Brazil
Contact:

Re: Unable to export rebars to IFC

Postby yorik » Thu Feb 02, 2017 6:51 pm

The problem is, the radius is already written into the IFC file by FreeCAD. But other applications export additional properties so when they read the file back, they can do special things with these properties. Revit does that a lot. But it is not something that is part of the IFC definition, it's each application that chooses to do like they want. So we need to know which IFC property needs to be there for solibri to see the radius. If you discover that, we can implement it in FreeCAD.

As for how IFC is implemented in FreeCAD, it is a much too big question to be responded here in a simple way. We basically use IfcOpenShell, and everything happens in src/Mod/Arch/importIFC.py. The insert() function takes care of importing, while the export() function does the export. I suggest you look at that file, and check the ifcopenshell website, there are a couple of python examples there that show how it works.