Importing animated FXB always fails?


I have been using Unity3d, but I wanted to give a try to UE4. But I seem to have trouble importing animations into UE.

I have FXB files that contain only bones and animation. I want to import them and use with my rigged characters. On import menu, I select “FXB animation” as my filetype. When trying to import any animated fxb file, there comes this unspecified error message:

Failed to import ‘…/…/…/…/…/…/…/blaa blaa/80_13.fbx’. Failed to create asset ‘/Game/80_13’

This happen with BOTH my own made animations (yes, FXB2014) AND 3rd party animations. There is no further explanation on UE log. These files work without problem in Unity3d.
If I try to import FXB file with bones, animation AND mesh, there is no error. But unfortunately, this method does not suit for my workflow. I would need to rework every single animation again and again to insert a mesh into them just to be able to import them into UE. Please tell me there is no such limitation in UE?

Search did not return any usable results. Could somebody be kind enough to tell me how do I import animated fxb into UE4?

Thank you!

Have you checked these pages and made sure everything is the way UE4 expects it. There is a difference between Unity and UE4 … even though they both support FBX.

Skeletal Meshes

FBX Animation Pipeline

The import section of the second link might be the most relevant to your current problem.

HTH. 8-}

qdelpeche, thank you for your reply!

According to FXB Animation pipeline:

“Currently, only a single animation for each Skeletal Mesh can be exported/imported in a single file.”

Yes, I have only one animation/file

“… Having a mesh bound to the skeleton is completely optional, though it makes the process of creating the animation much easier as you can see how the mesh is deforming during the animation. At export time, only the skeleton is required though.”

Yes, all this is correct with my files. To my understanding I have exported them as this documentation suggests.

I uploaded an example of the fxb that fails to import. If someone here in the forum had a time to try import it, I would appreaciate it.
Thank you.

I can’t test your animation, it’s kinda impossible to import animation without skeleton

If you open your skeletal mesh in the editor, click on the animation tab, then click the import button and import your animation that way, does it work?

zeOrb, just to make sure we are speaking with the same terms: When you say “skeleton”, do you mean the bone structure that has been animated on 3d software (3dsmax) and then exported? If yes, then I don’t understand what you mean there is no skeleton? There certainly should be skeleton/bones/biped in the file. Otherwise unity would not be able to use them either.
Sorry for this confusion…

Sorry, I mean I personally can’t test your animation because I don’t have initial file with skin + skeletal. Pure animation import in UE4 relies on skeletal mesh object I don’t have. I can’t press “Import” button, because I can’t chose base skeletal mesh for this animation

Thanks Mosel3y,

Doing it that way fails too. I can’t import the animations directly into a skeletal mesh, because I need to do in-editor retargeting. But in order to do so I should import the animation as a separate asset, as I have understood.

What if you need to do retargeting? In that case you can’t import the animation into already existing skeletal mesh, because their bone structures are different. That is exactly the problem I’m experiencing. I need to import the animation first, THEN do retargeting in order to use it with a skeletal mesh. Does this make any sense?


You still need to import your original skeletal mesh first … and then the animations … and then you can do retargetting.

Intro to Animation Retargetting in UE4

Animation Retargeting (Same Skeleton)
Animation Retargeting (Different Skeletons)

The links above should explain the whole process more clearly.

Yes, that is what I meant. I can import skeletal mesh without problem. But then I’m bumping into the problem I described in my first post. I can’t import any animation fxb (bones + baked animation, no mesh) because the unspecified error.
I will certainly read the retargeting manual you posted, once (and if) I get this animation import working.

That was I was talking about: I don’t have this skeletal mesh, thus I can’t test your animation. Would you mind to share skeletal mesh fbx?


Skeletal mesh

Thanks for looking!

Are you sure you sent right files?
Skeletons in skeletal mesh and in animation are completely different and incompatible

Thanks again,

Ok, perhaps I have misunderstood something. What I want to achieve is following:

  1. Use the skeletal mesh I sent as a character.
  2. Use the animation fxb as animation source.
  3. Yes they have different skeletons as they come from different source! They both have human bone structure, although in different order. I want to use UE retargeting to change all animations compatible with the character skeletal mesh. Basically this is the workflow with unity3d. Import character fxb → import animation fxb → tell Unity with rig editor what bones in the animation file are used as hip, spine, neck, etc…
    Perhaps I have misunderstood this whole process with UE?

So does this mean I can’t import animations that have not been strictly made for the skeletal mesh in the scene?
Then what is UE’s retargeting used for?

Hmmm…I believe Ue4 will only import an animation that already has a skeletal asset with the same bone hierarchy in the engine. Ue4 will however create a new skeletal asset when importing a skeletal mesh, in a bind pose. I come from unity as well, and Ue4’s animation system is a bit more complicated and less user friendly, but is more advanced if you know how to use it. Unlike unity’s mecanim retargeting system, Ue4’s re-targeting features are primarily used for sharing animation data between skeletal meshes already inside the editor. A way around this might be, create a skeletal mesh with the fbx file, just to allow the engine to create a skeletal mesh asset with a skeleton, then try and import the animations. Without the skeleton asset, the engine doesn’t know what to do with pure animation data unfortunately. (or you could just re target the animation in motion-builder instead). Ue4 was mainly targeted toward devs who have teams and create most of their stuff in house (this is changing a bit now), while unity is a very indie friendly engine, and is targeted toward people who don’t want to do all of the work (not saying everyone :D).


Thank you. I’m starting to understand now. It’s a bummer that this process seem to be more complicated than I hoped. I’ll be trying what you suggested.

KingTumTum101 hit the nail on the head.

  1. You need to import your model and skeleton in to UE4 first so that the skeletal mesh can be created.
  2. You then import your animations on to that skeletal mesh created in the step 1 above.
  3. Once this is done, you can then re-target your animations to a different skeleton (or the other way around).

The retargetting basically creates a duplicate animation targeted to the new skeletal mesh and does not override your original. I think this is what you post is asking about … 8-}

Glad I could be of service!

As an animator coming from Unity with little to no programming knowledge, and no dev team, UE4 seemed a bit daunting at first with a steep learning curve, and I’m still trying to figure many things out. But once you understand how UE4 works, with its many great features like Blueprint, and the things you can do with it, you may never want to go back to Unity. (I mean cmon, UE4 just went FREE. And even with the release of Unity 5, if you ask me there is no competition :D). Although things will seem very complicated at first, and you might have a bumpy start (you probably will), don’t give up on UE4! I thoroughly enjoy working with this engine. Every problem you encounter just makes you more experienced. And the community is great as well! I ask questions on the forum all of the time.

If you have any questions Ill do my best to help, since I’ve probably recently had the same ones. Id also love to see what you do with UE4.

I certainly feel welcomed and that’s more than I can say about unity support forums.
We have been kind of back and forth. We started our project with UDK3 and after about half of a year switched to unity. We had plenty of problems with UDK3. If we were developing a game with bots and laserguns, UDK would have been our choice (sarcasm intended :)). Now as UE4 is free it is certainly arousing interest. It’s too early yet to say if UE4 is going to stick. But in the end I think it depends how detailed documentation & tutorials UE4 offers. Unity3d really shines in this area.

Thanks everyone for your time and assistance!