Currently it’s not possible to unbind a single scene transform from an animator. It is only possible to call UnbindAllSceneHandles, which unbinds every previously bound scene transform and property. This makes it difficult to make changes to an animator’s bindings when some of those bindings are changing dynamically.
To give an example of why this would be useful for me, I have written a playable-based IK system, where multiple IK effectors may be simultaneously active for a single animator. The effectors are scene transforms used to adjust the target positions of various rig bones. Whenever I update an effector with a different transform,I have to unbind all scene handles, bind the new effector transform, and then rebind all the previously bound handles that didn’t need updating. This is inefficient and cumbersome to say the least. An API where I can dynamically unbind only the scene transform that needs updating would make my system significantly cleaner and faster.