[Fusion 360 Import] Importing current F3D files fails

[Anuril]

I've been toying around with migrating from Fusion 360 to FreeCAD and using the InventorLoader to import my F3D Files to FreeCAD.

That fails in Freecad 1.0.2 and it fails in the weekly build 2025.11.20.

I managed to get it to work, but it's not only this code in PR #101 that needs to be patched, it's also an upstream issue in FreeCAD which isn't going to fix itself at the moment. Here's my discoveries.

1. Trying to open an exported file from Fusion360 (Fusion Version 2605.1.18 x86_64) does not work with this error:

  File "C:\Program Files\FreeCAD 1.0\bin\Lib\site-packages\freecad\module_io.py", line 16, in OpenInsertObject
    getattr(importerModule, importMethod)(objectPath, *importArgs, **importKwargs)
  File "E:\PROFILES\<user>\AppData\Roaming\FreeCAD\Mod\InventorLoader\.\importerIL.py", line 148, in open
    _open(abs_file_name, skip, only, root)
  File "E:\PROFILES\ta\AppData\Roaming\FreeCAD\Mod\InventorLoader\.\importerIL.py", line 127, in _open
    reader = read(filename)
             ^^^^^^^^^^^^^^
  File "E:\PROFILES\<user>\AppData\Roaming\FreeCAD\Mod\InventorLoader\.\importerIL.py", line 70, in read
    if (importerF3D.read(filename)):
        ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\PROFILES\<user>\AppData\Roaming\FreeCAD\Mod\InventorLoader\.\importerF3D.py", line 174, in read
    folder = read_manifest(f3d, 'Manifest.dat')
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\PROFILES\<user>\AppData\Roaming\FreeCAD\Mod\InventorLoader\.\importerF3D.py", line 107, in read_manifest
    with f3d.open(path) as manifest:
         ^^^^^^^^^^^^^^
  File "C:\Program Files\FreeCAD 1.0\bin\Lib\zipfile.py", line 1627, in open
    return ZipExtFile(zef_file, mode, zinfo, pwd, True)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\FreeCAD 1.0\bin\Lib\zipfile.py", line 841, in __init__
    self._decompressor = _get_decompressor(self._compress_type)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\FreeCAD 1.0\bin\Lib\zipfile.py", line 740, in _get_decompressor
    _check_compression(compress_type)
  File "C:\Program Files\FreeCAD 1.0\bin\Lib\zipfile.py", line 720, in _check_compression
    raise NotImplementedError("That compression method is not supported")
<class 'NotImplementedError'>: That compression method is not supported

The issue is that the zipfile.py provided by Upstream Freecad can't unpack the f3d zipped file from Fusion. I've tried with 7-Zip and got the same error. I've noticed that my 7-Zip version was a bit out of date, so after updating, it could uncompress the f3d file just fine. I suspect the issue is that Autodesk updated their ZIP library which supports a newer compression type.

Workaround: Just uncompress the f3d file to a folder and re-zip it using Compression = Store (sometimes called 0)

2. After doing that, the import can then proceed, but then it says it can't interpret the manifest as because the code in Fix reading manifest in F3D importer #101 needs to be merged so that works again.

I've also managed to get the importer to crash when trying to import one of my files, but i didn't get a good log from Freecad on why it crashed, it just stops, but that should probably be in a separate issue but I don't have detailed information regarding why the crash happens. The Freecad Log says:

Msg: Reading: G:\3DDesign\convert\f\convert.f3d
Msg:     ... parsing 'FusionAssetName[Active]/Breps.BlobParts/BREP.07083386-ef75-41b6-8ffd-e4b38afb530e.smb'
Msg:     ... parsing 'FusionAssetName[Active]/Breps.BlobParts/BREP.280068e7-add6-45ff-ad20-8881441e647e.smbh'
Msg:     ... parsing 'FusionAssetName[Active]/Breps.BlobParts/BREP.5e53ad70-55cf-4e11-baff-7f0a4ec19835.smbh'
Msg:     ... parsing 'FusionAssetName[Active]/Breps.BlobParts/BREP.7381bb28-ce97-44d3-a0e3-5ee487813eff.smb'
Msg:     ... parsing 'FusionAssetName[Active]/Breps.BlobParts/BREP.c028670c-368f-46ea-acbf-2754ced582c1.smb'
Msg:     ... parsing 'FusionAssetName[Active]/Breps.BlobParts/BREP.d4c50b6a-5bc5-4079-9a02-7c96119c207f.smb'
Msg:     ... parsing 'FusionAssetName[Active]/Breps.BlobParts/BREP.f6de451d-2f72-4861-b11e-9fdd847060b9.smbh'

And the windows event log just says "Application Error" and no significant information:

 freecad.exe 
   1.0.2.0 
   6892a788 
   VCRUNTIME140.dll 
   14.44.35208.0 
   6b478ebd 
   c0000005 
   000000000000556c 
   6d28 
   01dc5c83bebaf18c 
   C:\Program Files\FreeCAD 1.0\bin\freecad.exe 
   C:\Program Files\FreeCAD 1.0\bin\VCRUNTIME140.dll 
   3b058385-c014-4c87-9808-b189ba7633b2 

[hansgeerdink]

Hi,
Perhaps not much of a contribution, but I can confirm the behavior.
Before rezipping:

19:06:19 Reading: C:\Users\Hans\Desktop\FreeCadFiles\FusionToFreeCAD\k3floydrosehals.f3d 19:06:19 ... parsing 'FusionAssetName[Active]/Breps.BlobParts/BREP.1ecee48a-a603-4e2d-8740-4a5e98ab26d2.smb' 19:06:22 pyException: Traceback (most recent call last): File "<string>", line 2, in <module> File "C:\FreeCAD_weekly-2025.11.20-Windows-x86_64-py311\bin\Lib\site-packages\freecad\module_io.py", line 18, in OpenInsertObject getattr(importerModule, importMethod)(objectPath, *importArgs, **importKwargs) File "C:\Users\Hans\AppData\Roaming\FreeCAD\v1-2\Mod\InventorLoader\.\importerIL.py", line 148, in open _open(abs_file_name, skip, only, root) File "C:\Users\Hans\AppData\Roaming\FreeCAD\v1-2\Mod\InventorLoader\.\importerIL.py", line 135, in _open reader.create3dModel(root , doc) File "C:\Users\Hans\AppData\Roaming\FreeCAD\v1-2\Mod\InventorLoader\.\importerF3D.py", line 205, in create3dModel strategy = chooseImportStrategyAcis() ^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\Users\Hans\AppData\Roaming\FreeCAD\v1-2\Mod\InventorLoader\.\importerUtils.py", line 310, in chooseImportStrategyAcis strategy = resultMapping[result] ~~~~~~~~~~~~~^^^^^^^^ <class 'KeyError'>: 3

After rezipping:

19:30:19 Reading: C:\Users\Hans\Desktop\FreeCadFiles\FusionToFreeCAD\k3floydrosehals1.f3d 19:30:19 ... parsing 'FusionAssetName[Active]/Breps.BlobParts/BREP.1ecee48a-a603-4e2d-8740-4a5e98ab26d2.smb' 19:30:21 DONE!

Then nothing (seems to) be happening and the file is locked by FreeCAD.
Seems, because a directory is created with the exported files in it.
When trying to import the .smb and/or .sat files separately, the same result is shown as importing the freshly rezipped .f3d file.

As mentioned before, perhaps not much of a help.
Really interested in any follow ups regarding this add-on!

Cheers,
Hans

[pjcreath]

File "C:\Program Files\FreeCAD 1.0\bin\Lib\zipfile.py", line 720, in _check_compression
    raise NotImplementedError("That compression method is not supported")

The issue is that the zipfile.py provided by Upstream Freecad can't unpack the f3d zipped file from Fusion. ... I suspect the issue is that Autodesk updated their ZIP library which supports a newer compression type.

Sadly, zipfile is provided by Python, and FreeCAD currently incorporates Python 3.11.

Can you attach an f3d file that exhibits this behavior? I'd like to see if any later version of Python supports this new compression method.

[Anuril]

File "C:\Program Files\FreeCAD 1.0\bin\Lib\zipfile.py", line 720, in _check_compression
    raise NotImplementedError("That compression method is not supported")

The issue is that the zipfile.py provided by Upstream Freecad can't unpack the f3d zipped file from Fusion. ... I suspect the issue is that Autodesk updated their ZIP library which supports a newer compression type.

Sadly, zipfile is provided by Python, and FreeCAD currently incorporates Python 3.11.

Can you attach an f3d file that exhibits this behavior? I'd like to see if any later version of Python supports this new compression method.

Can't right now.
Python 3.11 above 3.11.14 works, and for the other versions, see this issue for more details.

[stdedos]

vimle-leg-105mm.f3d.zip

Example F3D that fails

10:38:22  Reading: ~/d/vimle-leg-105mm.f3d
10:38:22      ... parsing 'FusionAssetName[Active]/Breps.BlobParts/BREP.beb7f4ac-8eb8-4876-b57a-5c7a1576b38e.smb'
10:38:22      ... parsing 'FusionAssetName[Active]/Breps.BlobParts/BREP.8ed9593a-42f2-41ef-a09c-75396bc8c783.smbh'
10:39:08  pyException: Traceback (most recent call last):
  File "<string>", line 2, in <module>
  File "/app/lib/python3.12/site-packages/freecad/module_io.py", line 16, in OpenInsertObject
    getattr(importerModule, importMethod)(objectPath, *importArgs, **importKwargs)
  File "~/.var/app/org.freecad.FreeCAD/data/FreeCAD/Mod/InventorLoader/./importerIL.py", line 148, in open
    _open(abs_file_name, skip, only, root)
  File "~/.var/app/org.freecad.FreeCAD/data/FreeCAD/Mod/InventorLoader/./importerIL.py", line 135, in _open
    reader.create3dModel(root , doc)
  File "~/.var/app/org.freecad.FreeCAD/data/FreeCAD/Mod/InventorLoader/./importerF3D.py", line 205, in create3dModel
    strategy = chooseImportStrategyAcis()
               ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/.var/app/org.freecad.FreeCAD/data/FreeCAD/Mod/InventorLoader/./importerUtils.py", line 310, in chooseImportStrategyAcis
    strategy = resultMapping[result]
               ~~~~~~~~~~~~~^^^^^^^^
<class 'KeyError'>: 3

OS: KDE Flatpak runtime (ubuntu:GNOME/ubuntu/xcb)
Architecture: x86_64
Version: 1.0.2.39319 (Git) Flatpak
Build type: Release
Branch: (HEAD detached at 256fc7e)
Hash: 256fc7eff3379911ab5daf88e10182c509aa8052
Python 3.12.12, Qt 6.9.3, Coin 4.0.3, Vtk 9.3.1, OCC 7.8.1
Locale: English/United States (en_US)
Stylesheet/Theme/QtStyle: FreeCAD Light.qss/FreeCAD Light/
Installed mods: 
  * sheetmetal 0.7.65
  * InventorLoader 1.5.1