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Long-Standing Content Import Bug

I’ve bounced off Unreal Engine 4 numerous times because of one long-standing issue that has been present at least since 4.4, probably always.

I’ve got many FBX files containing either multiple meshes or multiple animation tracks. The Unreal Engine Editor invariably destroys my assets when I hit ‘Reimport’. For example, assume I’m creating a visual novel style game. In Blender I set up a scene (say, a room or a sidewalk), link my actors into the scene and create some animation clips. Then I simply export them all into a one FBX file. Or assume that I’m building a set of modular wall pieces, so I’ll put all the walls pieces into the same scene to make sure they fit together and then export them to FBX, unchecking ‘Combine Meshes’ in the Unreal Editor.

The initial import is always fine. All my animation clips are cleanly and automatically separated and adequately named:
7027eb8cc4ff2b706fa2d4c5655c8c8d71287a33.png

Some time later I tweak my animations a bit, export them to FBX again and hit ‘Reimport’ in Unreal Editor. This is what I get:
6ca5078a7dd4160212bb50e1773918f16bdacce1.png

(editor log)

It has imported the ‘Dead’ animation five times. All animations now show the character lying dead on the floor. And since animations are somehow linked by an opaque GUID embedded in the .uasset, after deleting all animations and importing them from scratch, I have the pleasure of tracking down all uses of those animations and manually replacing them with the new import. The same thing happened with FBX files containing multiple meshes, but I wasn’t able to reproduce this in 4.12, so maybe that part has been fixed.

Also, what is the workflow should I decide to add a new mesh or animation to my multi-mesh/multi-animation FBX file?
I only have the individual meshes/animations in the Content window, so where do I click reimport? If I drag the FBX file into the Unreal Editor’s content window, it will do an import-from-scratch with all the drawbacks involved (breaking all asset links and resetting any material assignments in the case of a mesh).

Not even an acknowledgement. Should I report this in the new bug tracker then?

In the meantime I’ll look for a workaround.

You definitely should.

I’m not sure if this has been reported or not, but please post on the AnswerHub in the Bug Reports section and any details needed to reproduce the issue on our end. Once reported we can assign out to one of the Support Techs to investigate.

Thank you!

Tim