UE5 Fullbody IK shows bizarre behavior

When following the example from the wiki I was able to setup the Full Body IK node for the mannequin without any problems. Currently, I am testing the Full Body Ik feature with a custom model that I am still working on but I am encountering some very strange behaviour when I am trying out the Full Body IK node with my own model.

For starters, the root bone is showing up as a red bone.

Another model with almost the same skeleton, however, does not show up with a red root bone.

Second, when creating a control gizmo the gizmo itself is absurdly huge.
I can scale the gizmo of course but I don’t understand why it is not appropriately sized.

Lastly and the main issue:
When setting the root bone of the Fullbody IK node to the root and add set an effector bone the whole mesh warps into whatever that is.

I have no idea if these issues are specific to the Fullbody IK or not but I have not encountered these issues before.

I have the same problem with mesh deformation. All my models that I exported from blender behave the same way. Unreal Mannequin works fine.

I wish I could share a solution with you but I too am still experiencing this problem.

Hello! Take a look at blender export settings on this video (specially the part concerning armature scale and primary/secondary bone) to solve the scale issue with the gizmos.

Assuming you’re using blender to make your characters :smiley:

As for the red bone, I bet it’s because your root bone isn’t at world origin (0,0,0).

Thanks and good luck!