Howdy. I have the following problem: the fbx files exported from iClone are super large, because they always include the skeletal mesh. So I wanted to export it via 3dxchange, where I have the option to exclude geometry (God knows why iClone is missing this feature), but import in UE4 fails due to the lack of root bone animation data. I probably could import my skeletal mesh first time from the 3dxchange as well, but then I would not be able to use the Auto Setup plugin in engine. So what should I do to have an fbx file with animation data only, that will be compatible with the skeleton created from the iClone based fbx.

The way I tried to export from 3dxchange was:
1. in iClone, i have loaded my custom avatar (that i have previously exported to UE4 to get my skeletal mesh)
2. I have applied the motion to the avatar
3. Clicked 'edit in 3dxchange' to send my avatar to 3dxchange
4. Used 'Collect Clip' to send the motion to 3dxchange
5. in 3dx I have added my motion to the perform editor (the only motion there)
6. Clicked export to FBX, selected Unreal preset, and unchecked "Include Geometry"
7. When trying to import to UE4, the engine properly recognizes that it is an animation-only fbx, I select the skeleton of my CC/iClone made avatar, but I get the error message that import has failed because "Mesh contains root bone as root but animation doesn't contain the root track"

I shall also add, that when I use the same avatar in iClone and export fbx from there, and import it in UE4 (i uncheck import mesh, so that only animation is imported) it works like a charm. But this option generates a ~10mb file for every animation fbx file, which is definitely above the budget I aim for. I also don't want to have a single super bloated fbx with skeletal mesh + all the animations for it.

So if anyone could help me how to export animation-only fbx (either via 3dxchange or iClone, whatever works), I'd be much obliged

Cheers!