Incorrect geometries when exporting part to ifc

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dcapeletti
Posts: 452
Joined: Wed Jul 23, 2014 2:27 pm

Incorrect geometries when exporting part to ifc

Post by dcapeletti » Sun Apr 26, 2020 1:57 pm

Hi, I have some parts designed in part desing that I need to export to .ifc format
The problem is that when I export them, the geometries are incorrect.

I've attached images so you can check the result. I also attached the file so you can test it and determine how I can export correctly to ifc.

As you can see, the geometries in the resulting images are incorrect, the roundings are missing and the protruding cylinders are square.

Thanks

OS: Debian GNU/Linux 9 (stretch) (GNOME/default)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.20639 (Git) AppImage
Build type: Release
Branch: master
Hash: 45aef7b028a54c5420db49ff3284fc7377475e90
Python version: 3.8.2
Qt version: 5.12.5
Coin version: 4.0.0
OCC version: 7.4.0
Locale: Spanish/Argentina (es_AR)
Attachments
ifc preferences export.png
ifc preferences export.png (42.4 KiB) Viewed 299 times
part desing.png
part desing.png (49.53 KiB) Viewed 302 times
test.ifc
(111.34 KiB) Downloaded 4 times
test ifc.png
test ifc.png (106.75 KiB) Viewed 302 times
Part.FCStd
(50.25 KiB) Downloaded 6 times

Syres
Posts: 704
Joined: Thu Aug 09, 2018 11:14 am

Re: Incorrect geometries when exporting part to ifc

Post by Syres » Sun Apr 26, 2020 2:19 pm

Try these settings:
IFC_Export_Settings.jpg
IFC_Export_Settings.jpg (41.97 KiB) Viewed 293 times
I also use IFCQuery as an independent check of the output but you'll have to compile it for Linux I believe.

EDIT: If the cylinders still appear incorrect then I'm inclined to highlight OCC 7.4 as a possible issue

OS: Windows 7 SP 1 (6.1)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.20634 (Git)
Build type: Release
Branch: master
Hash: ba34cc6a96c15d64224e8f0c8b5da874f1e03a07
Python version: 3.6.8
Qt version: 5.12.1
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/United Kingdom (en_GB)

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dcapeletti
Posts: 452
Joined: Wed Jul 23, 2014 2:27 pm

Re: Incorrect geometries when exporting part to ifc

Post by dcapeletti » Sun Apr 26, 2020 5:28 pm

Indeed, the corners come out rounded and the central emptying also comes out. Now the cylinders still come out square.

On the other hand, I would like to add information to the IFC by checking the option "Export full freecad parametric model", but when loading it, the center emptying does not appear and the rounded corners do not appear either. I'm attaching images.
Attachments
test ifc2.png
test ifc2.png (27.57 KiB) Viewed 276 times
test ifc Export a parametric freecad model.png
test ifc Export a parametric freecad model.png (52.3 KiB) Viewed 276 times

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dcapeletti
Posts: 452
Joined: Wed Jul 23, 2014 2:27 pm

Incorrect geometries when exporting part to ifc

Post by dcapeletti » Sun Apr 26, 2020 5:30 pm

Hi, I just posted a thread on https://forum.freecadweb.org/viewtopic.php?f=3&t=45698 but maybe I should have posted it here. Please some moderator, I could move it. Thanks

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bernd
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Location: Zürich, Switzerland

Re: Incorrect geometries when exporting part to ifc

Post by bernd » Mon Apr 27, 2020 11:44 am

done

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bernd
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Re: Incorrect geometries when exporting part to ifc

Post by bernd » Mon Apr 27, 2020 11:48 am

export and reimport works great here ...

part1.ifc
(119.96 KiB) Downloaded 5 times

screen.png
screen.png (323.31 KiB) Viewed 243 times

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bernd
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Re: Incorrect geometries when exporting part to ifc

Post by bernd » Mon Apr 27, 2020 11:50 am

dcapeletti wrote:
Sun Apr 26, 2020 5:28 pm
On the other hand, I would like to add information to the IFC by checking the option "Export full freecad parametric model",
this is only full parametric in sense of Arch Objects not in sense of Part or Part Design, AFAIK.

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bernd
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Re: Incorrect geometries when exporting part to ifc

Post by bernd » Mon Apr 27, 2020 11:57 am

in case of the mesh triangles play with these prefs. I changed them and there is totally different ifc ...

part2.ifc
(239.71 KiB) Downloaded 4 times

screen.png
screen.png (70.22 KiB) Viewed 235 times

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bernd
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Re: Incorrect geometries when exporting part to ifc

Post by bernd » Mon Apr 27, 2020 11:58 am

this due to the way the shape is exported to ifc. If it can not be exported as Arch extrusion than the shape will be exported as face set. Thus the shape needs to be meshed before, thus the DAE preferences will be used to mesh the shape. Thus different DAE prefs different ifc ...

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bernd
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Re: Incorrect geometries when exporting part to ifc

Post by bernd » Mon Apr 27, 2020 12:00 pm

Hopefully this will improve with IFC4 which is capable of nurbs. FreeCAD should be able to write such nurbs to IFC4 but I have failed on any test to do so.

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