When I try to retarget an animation from a custom skeletal mesh in UE 5.4 I get the error message IK ‘Retargeter could not find source root bone, None in mesh AnimBaseCharacter’. The custom skeleton literally has a root bone named ‘root’ which is in the same location (on the floor) as the metahuman skeleton I am trying to re-target it to. Is there any way I can get it to recognise the root bone, or am I damned to keep using the old retargeting method ?
Bumping this, I have the same issue. Trying different configurations on my skeleton, all with a root bone called ‘root’ and I still get the error ‘IK Retargeter could not find target root bone’.
The auto retargeter works with skeletons made for Unreal, but I’m having no luck with Accurig or Mixamo skeletons
I was having this issue so I looked into the source code. Auto retargeter works by applying ‘templates’ to the source/target mesh. If your character mesh does not match one of the pre-created templates, auto retargeter doesn’t know what to do. There’s quite a few templates available, you can view them in the engine file IKRigAutoCharacterizer.cpp. There’s one for Mixamo, Daz, CC4, UE4 manny, UE5 manny, and more. If you have a custom model or sourced a model from some uncommon source, there may not be a template available. And even if you do use a supported character, if the rig has any differences in bone naming hierarchy or indexes from the expected input it may not work properly (example: Mixamo template expects root bone to be named “Hips”, not “root”).
If you want to see if your character has a supported template or figure out why a supported rig may not be working properly, open IKRigAutoCharacterizer.cpp, find the template, look at the bone names, bone indices, and expected root bone name and ensure everything matches properly