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Maniphest T50405

FBX Export "!EXPERIMENTAL! Apply Transform" with nested objects resets after one recursion
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Description

System Information
Windows 10, i7 3770k, 16GB, nVIDIA GTX 670

Blender Version
Broken: 2.78

Short description of error
I have six cubes nested together where Cube2 is the child of Cube1, Cube3 is the child of Cube2 and so on. Imagine they are placed in world positions A through F. If I export them as an FBX and re-import that same FBX, Cube1 is now in position A, Cube2 is in position B, Cube3 in A, Cube4 in B, Cube5 in A, and Cube6 in B.

Exact steps for others to reproduce the error

  • Load the attached .blend file
  • Select any of the hierarchies prefixed with "Export"
  • Export as FBX 7.4 binary, Use selection, Scale 1, Z Forward, Y Up, Enable "!Experimental! Apply Transform", Remaining settings can be default
  • Import the FBX that you just created using default settings - ensuring "!Experimental! Apply Transform" is not checked
  • Notice that all elements of the imported hierarchy only occupy the locations of the first two elements in the exported hierarchy

cubetest.blend526 KBDownload

Note: This is my first bug report, so apologies if I missed something. I tried seeing if there were existing tasks discussing the same error but did not find any. I am attempting to get Blender to export FBX files that display correctly in Autodesk FBX Review and also import correctly into Unity without rotation and scaling errors.

Event Timeline

Steven Smith (lrg_steven) created this task.Jan 10 2017, 12:15 AM
Aaron Carlisle (Blendify) assigned this task to Bastien Montagne (mont29).Jan 10 2017, 3:04 AM
Aaron Carlisle (Blendify) edited projects, added Add-ons (Community); removed BF Blender.
Aaron Carlisle (Blendify) added a project: Import/Export.Jan 10 2017, 4:18 AM
Bastien Montagne (mont29) changed the task status from Unknown Status to Unknown Status.Jan 10 2017, 5:38 PM

Thanks for the report, but there is a very good reason this setting is marked as experimental - it’s not working in many cases besides basic ones. This considered a known limitation currently, not a bug.

Steven Smith (lrg_steven) added a comment.Jan 10 2017, 5:53 PM

Thanks for the quick response. I understand this is experimental but assumed that experimentation was ongoing. Is the current limitation for static mesh export a hierarchy depth of 2? If so, I'll just build my pipeline around that limitation or write a specific exporter of my own (for my very specific use cases).

Bastien Montagne (mont29) added a comment.Jan 10 2017, 6:14 PM

Unfortunately FBX has proven to be extremely frustrating and infuriating, and I’m just sick of it beyond any hope. So I do basic maintenance for it, but do not intend to actively work on that… thing in any foreseeable future.

That said, if you want to check the code to try to fix that issue, I’d be happy to review a patch. But be warned, I already spent a significant amount of time on that specific issue (getting 'apply transform' to work better and in more cases), this is a rather complex nest of transform matrices… :/

Steven Smith (lrg_steven) added a comment.Jan 10 2017, 6:57 PM

Hahaha! Yes, that is why I added the caveat of "my very specific use cases". I can imagine how tangled things would get when you try to support even a fraction of what Blender can do. If I do make any discoveries though, I'll definitely share them. Thanks again.

Simeon Conzendorf (noemis) added a subscriber: Simeon Conzendorf (noemis).Feb 17 2021, 10:51 AM