Unity Rig Error: Ambiguous Transform 'CC_Base_Hip' with Tail Spring Bones

Pipeline Unity
1

Hi everyone,

I’m running into a persistent issue when exporting a character/scene with a character with a tail with spring bone and/or scene from Character Creator 5 / iClone 8 to Unity. Every time I transfer the scene, or the character, or send it in a fbx and compile it with the plugin I obtain this error:

Rig Error: Avatar creation failed:
Ambiguous Transform ‘CC_Base_BoneRoot/CC_Base_Hip’ and ‘CC_Base_BoneRoot/CC_Base_Hip/CC_Base_Pelvis/Tail/CC_Base_Pivot/Tail_001/CC_Base_Hip’ found in hierarchy for human bone ‘Hips’. Transform name mapped to a human bone must be unique.

UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)

It seems that during the export process, the bone where the tail spring bones are attached is being placed again, the result is that “CC_Base_Hip” is twice and, the second time, under itself. Creating a name/bone conflict.

Because of this naming ambiguity, the Unity Humanoid Avatar fails to map correctly, which breaks the Timeline and all character animations and the fbx with the animation can’t be paired with the character to use it in the timeline.

Has anyone encountered this specific naming conflict with tails/spring bones before? Is there a way to force a unique name for the tail attachment point during export to avoid this overlap?

Any help or workarounds would be much appreciated.

Thanks!

2

Hi losdra1,

There is currently a known issue with the Unity Auto Setup, and we will update this in a future version.

As a workaround, you can transfer the character from CC to Blender to let it automatically remove the duplicate bones. Then, import it back into CC to apply the animation before sending it to Unity.

Thank you for your assistance!

3

Hi raytsao_RL,

Thank you for the update. I tried the Blender workaround to remove the duplicate bones, but unfortunately, the tail doesn’t work correctly after importing the character back into CC. The spring bones don’t work and the bone hierarchy seems incorrect, but I’m not sure how to fix it.

When I activate the spring bones, the tail root moves instead of being fixed to the hips bone, making the tail look like it’s not part of the character.

Is there an estimated date for the Unity Auto Setup update? Also, how long has this bug been known?

Thank you for your assistance!

4

Hi,

We recently identified this issue and are currently working on a fix.

Regarding the workflow, I apologize for the confusion. You don’t need to manually remove any bones in Blender; it will automatically rename the duplicate ones for you. Simply import the character into Blender, send it back to CC, and then export to Unity.

If the issue persists, please record your process and send the project file to raytsao@reallusion.com.

Thank you for your patience!