IFC files from structural engineering software CSI ETABS

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ebrahim raeyat
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IFC files from structural engineering software CSI ETABS

Postby ebrahim raeyat » Thu Dec 06, 2018 7:11 pm

@yorik Thanks so much. I have been imported CSI ETABS ifc file into FreeCAD with succeed:
etabs.png
etabs.png (228.32 KiB) Viewed 212 times
f1.png
f1.png (19.61 KiB) Viewed 212 times
f2.png
f2.png (43.78 KiB) Viewed 212 times
It seems all aspect ratios of lengths is correct, but in properties panel all height dimentions set to 1000 mm and width to 100 mm.

thanks so much.

OS: Manjaro Linux
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15303 (Git)
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Branch: master
Hash: 6199c95fd71eacb9cc168426e55254aa79a42034
Python version: 3.6.7
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bernd
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Re: BIM module development / enhancement

Postby bernd » Thu Dec 06, 2018 9:41 pm

Cool. The file you exported from CSI ETABS is a Architectural View IFC. This ifc has volumes.

It seams CSI ETABS ist also able to export an structural analysis view ifc. Such an ifc has only edges and faces, means you export the structural geometry to ifc. (your picture one). FreeCAD can also impoort such an ifc if you activate the import in preferences.
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ebrahim raeyat
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BIM module development / enhancement

Postby ebrahim raeyat » Fri Dec 07, 2018 2:52 am

Thanks @bernd. yes it has structural layer for ifc:

ifc.png
ifc.png (19.4 KiB) Viewed 186 times

but when i select that, nothing imported and this error appeared:

Code: Select all

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/home/ebi/Applications/squashfs-root/usr/Mod/Arch/importIFC.py", line 446, in insert
    additions.setdefault(r.RelatingStructure.id(),[]).extend([e.id() for e in r.RelatedElements])
  File "/home/ebi/Applications/squashfs-root/usr/Mod/ifcopenshell/entity_instance.py", line 63, in __getattr__
    self.wrapped_data.get_argument(self.wrapped_data.get_argument_index(name)))
  File "/home/ebi/Applications/squashfs-root/usr/Mod/ifcopenshell/ifcopenshell_wrapper.py", line 1960, in get_argument
    return _ifcopenshell_wrapper.entity_instance_get_argument(self, *args)
<class 'RuntimeError'>: Token $ at 266018 invalid instance name
it also can export to IGES and STEP formats, but none of them work in freecad:

export1.png
export1.png (33.24 KiB) Viewed 186 times

Code: Select all

Traceback (most recent call last):
  File "<string>", line 1, in <module>
<class 'RuntimeError'>: FreeCAD exception thrown ()
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bernd
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Re: BIM module development / enhancement

Postby bernd » Fri Dec 07, 2018 7:10 am

wow cool, would you provide a simple file which creates the error? With a file I could tackle down the problem.
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bernd
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BIM module development / enhancement

Postby bernd » Fri Dec 07, 2018 7:12 am

step and iges should work in FreeCAD too, but we shoulx go step by step, means IFC first. I may move this in a separate topic.

bernd
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ebrahim raeyat
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Re: BIM module development / enhancement

Postby ebrahim raeyat » Fri Dec 07, 2018 10:57 am

bernd wrote:
Fri Dec 07, 2018 7:10 am
wow cool, would you provide a simple file which creates the error? With a file I could tackle down the problem.
yes, this is my file:
struc.ifc
(263.02 KiB) Downloaded 2 times
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bernd
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Re: IFC files from structural engineering software CSI ETABS

Postby bernd » Fri Dec 07, 2018 12:32 pm

I get ...

Code: Select all

Opening  C:/Users/BHA/Desktop/struc.ifc ...done.
Building relationships table...Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\0_BHA_privat\progr\FreeCAD_0.18.xxxxx_x64_dev_win\Mod\Arch\importIFC.py", line 446, in insert
    additions.setdefault(r.RelatingStructure.id(),[]).extend([e.id() for e in r.RelatedElements])
  File "C:\0_BHA_privat\progr\FreeCAD_0.18.xxxxx_x64_dev_win\bin\lib\site-packages\ifcopenshell\__init__.py", line 50, in __getattr__
    return entity_instance.wrap_value(self.wrapped_data.get_argument(self.wrapped_data.get_argument_index(name)))
  File "C:\0_BHA_privat\progr\FreeCAD_0.18.xxxxx_x64_dev_win\bin\lib\site-packages\ifcopenshell\ifcopenshell_wrapper.py", line 1340, in get_argument
    return _ifcopenshell_wrapper.entity_instance_get_argument(self, *args)
<type 'exceptions.RuntimeError'>: Token is not an integer or identifier


with my rare geometry importer I get ...


screen.jpg
screen.jpg (139.4 KiB) Viewed 146 times


I will have a look ...
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yorik
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BIM module development / enhancement

Postby yorik » Fri Dec 07, 2018 12:39 pm

That's interesting. To create the arch model, etabs apparently just "extrudes" the analytic lines. You can see that objects are not well joined. We could do a far better job in freecad...

All Arch structure objects (columns, beams, slabs...) have a Nodes property which is a sequence of 3D vectors, that can represent a line or polyline. If the Role property of the object is set to "Slab", then if there are at least 3 points, it represents a face. (I'm thinking this ability should be separated in a separate property). The position of these nodes is calculated automatically taking the central fiber of the element, but it can also be edited manually, giving total control.

I never pushed these concepts further than that, but I think everything is there to have a good workflow already. One of these days we need to try to model an example building, which is exportable as both a coherent arch and structural IFC model... I haven't looked much at how one can "bind" a structural line and an arch object in IFC (ie. inform that they relate to the same object)

Also, being able to import an arch ifc, then a struct ifc of the same model, and have both "magically" reassembled would be kick-ass!
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bernd
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Re: IFC files from structural engineering software CSI ETABS

Postby bernd » Fri Dec 07, 2018 2:17 pm

yorik wrote:
Fri Dec 07, 2018 12:39 pm
One of these days we need to try to model an example building, which is exportable as both a coherent arch and structural IFC model... I haven't looked much at how one can "bind" a structural line and an arch object in IFC (ie. inform that they relate to the same object)
Oh yes we should and AFAIK it is not possible but I may be wrong. It would be cool if it would be possible !

yorik wrote:
Fri Dec 07, 2018 12:39 pm
Also, being able to import an arch ifc, then a struct ifc of the same model, and have both "magically" reassembled would be kick-ass!
YEAH !
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bernd
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Re: IFC files from structural engineering software CSI ETABS

Postby bernd » Fri Dec 07, 2018 4:40 pm

with a hack I was able to import the struct file. See attached screen. ETABS generates some rubbish IFC. In an strutural analysis model of an engineer in any case the members are connected. But they are not !!! Have a look at the picture no column is connected to the slab! Is there some preference in ETAB to connect the columns to the slab for the exported IFC?

Bernd
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screen.jpg
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