[IFC EXPORT] Strange behavior on export

[walpa]

Hi all,

Before exporting to IFC:

print_1.png (143.36 KiB) Viewed 7614 times

After export:

print_2.png (141.54 KiB) Viewed 7614 times

The element indicated in the figure changes position automatically and is exported in this new position (when imported into Blender, it is in the wrong place).

And the groups are being exported as IFCBUILDINGELEMENTPROXY and not IFCGROUP

print_3.png (93.38 KiB) Viewed 7614 times

Help, what am I doing wrong?

OS: Linux Mint 19.3 (X-Cinnamon/cinnamon)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24291 (Git) AppImage
Build type: Release
Branch: (HEAD detached at 0.19.2)
Hash: 7b5e18a0759de778b74d3a5c17eba9cb815035ac
Python version: 3.8.8
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.4.0
Locale: Portuguese/Brazil (pt_BR)


Thanks

[balrobs]

I can confirm here.
Same when I open the exported IFC file in BIMcollab ZOOM.
Maybe a problem with the IFC exporter code?

Code: Select all

OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.20.25452 (Git)
Build type: Release
Branch: master
Hash: b0b4b321cb7e90a15311c0a1deea35d618706733
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.0
Locale: German/Germany (de_DE)

[Roy_043]

If I recompute the whole document the offending wall also changes position in FreeCAD.

[balrobs]

If I recompute the whole document the offending wall also changes position in FreeCAD.

Yes! Even if I recompute only the offending wall its position changes. Obviously the culprit isn't the IFC exporter but some strangeness with the offending wall.
BTW moving the wall to its correct position solves the problem definitely.
Cheers!

[walpa]

If I recompute the whole document the offending wall also changes position in FreeCAD.

Recompute hasn't changed anything here.

BTW moving the wall to its correct position solves the problem definitely.
Cheers!

Yes, I noticed that too.
In this (relatively small) project, this change is visible, but what if it was a big project and it happened without being identified? Reliability goes to space...
The procedure I used to draw this structural wall is the same as the others: create beam, select two points, then set parameters.
I did some testing and found that the order of selection of points in creating this wall/beam makes a difference. Left to right does not cause repositioning, right to left causes this behavior on export. I redid some beams changing the order of the points and the problem did not occur.
Strange...
Cheers too!

[bernd]

have you tried to set "force brep" to true. This is not standard but higthly recomended to export robust models. With this setting to false there have seen various problems ....

[balrobs]

If I recompute the whole document the offending wall also changes position in FreeCAD.

Recompute hasn't changed anything here.

In order to localize better the problem I took your file Estrutural_to_esport.FCStd, deleted everything except the object par-003 and saved it under Estrutural_to_export_01.FCStd.
Then I opened the new file, selected the object par-003 in the object-tree and with a right mouse click started the recompute-object command. The result was a flipping of the object. Notice that I only worked with FreeCAD files and objects and didn't use IFC at all. I also can't see any error messages!
BTW the interested object isn't a wall but a beam created with the BIM workbench, isn't it?
Maybe @Yorik can help us to understand what's going on here?
Cheers to all!

Here is my test file:

Estrutural_to_export_01.FCStd

(10.58 KiB) Downloaded 171 times

[paullee]

Suspected there is some hidden bug :-

Trying to play around what Arch Structure is capable and opened the OP's file.

Not only par-004 flip in direction, I had once revised the Height of par-004, and it also change direction ! But can't reproduce that.

Note both par-003 and par-004 have Axis-z = -1


Hope anyone has more idea

Screenshot from 2021-09-04 23-47-36.png (333.19 KiB) Viewed 7303 times

[thomas-neemann]

if you need a quick transitional solution, you could make a simple copy in part before the export and export it. it is enough to get the geometry.

[walpa]

have you tried to set "force brep" to true. This is not standard but higthly recomended to export robust models. With this setting to false there have seen various problems ....

I tried but the behavior persisted.