I have a problem with ARP fbx exporter. When I’m using it, it’s rename root bone to root_aprbaseobject. Everything was OK until I started adding root motion animations which are not working. I’m certain that’s the problem but I can’t find the way to remove that ‘_aprbaseobject’ suffix from root bone name.
Armature in Blender is named Root as it should and also APR exporter watch over that detail too.
I know that I can use default exporter where there is no problem with that matter but I want to use converter for bone names.
You have no idea how much trouble you have saved me.
For those coming from the future: Using Blender 4.0, if you want a proper ROOT BONE for root motion in Unreal Engine, have everything parented to a Root Bone (no deformation) and have it as the only parent under your bone armature.
Then, have both your main armature (the orange man icon) and the inner Armature (the green stick figure icon both in the Scene Collection) named “Armature”. Make sure your main root bone is named “root”.
Then bam, your main root bone when loading the skeletal mesh in Unreal Engine will be your assigned Root bone from Blender!
@SkinnyMouse481 Which FBX exporter are you using that has this behavior?
edit: I could do this with the default Unreal FBX Exporter, and the Auto Rig Pro exporter (note: to do this in ARP, make sure your armature is NOT named “Armature”, and that the exporter options set “Rig Name” to “Armature”. It will add a suffix if the armature is already named “Armature”)
Appears to be undocumented Unreal importer behavior, I guess it’s hardcoded to strip out a root bone named “Armature” if it sees one?
Some more notes for people struggling in the future:
So, Unreal 5.4 fixed many Blender FBX import bugs, but there is still one big one:
Local (bone space) translations of bones will be 0.01x what they actually should be.
Most of the time this doesn’t matter, but it still has this artifact lying around, and you won’t notice it until it silently causes problems later.
This matters because, if you do the above and let unreal’s importer strip out the Armature root bone, then when you import an FBX animation, it will not properly read scale conversion that your FBX exporter in Blender set. Your animation will be 100x too small. And nothing you set in your export settings will correct it.
At that point, the only way to fix it is to set scale to 100.0 in Unreal’s Fbx importer. Pretty undesirable IMO.
If you’re an Auto Rig Pro user, ARP seems to more rigorously apply scale conversion in its FBX exports, and it sidesteps the local translation bug above.
tl;dr: Unreal’s FBX support is improving but still has drastic pitfalls like this. Test your pipeline rigorously.
(Note: I don’t think Blender’s default FBX exporter is necessarily bugged, I do generally think it’s Unreal’s “fault” here. There are multiple ways to write an FBX file and it seems Unreal’s importer could do more to account for different formats. I hope Epic continues to improve Blender support).
