With the API is there a way to add a blendtree to a substate machine? Or move a state into a substate machine? There is AnimatorController.CreateBlendTreeInController that creates a blend tree in the root. (it also makes the object this strange sub-object under the Controller in the project window). But there is no way that I have found to move the state into the sub state machine. If I just do new BlendTee() and set that as the motion on the State, it looks like it is setup correctly but if I click away or close unity it mystically disappears as if it was never there. If I create this and use AddState to try and rechild it I get a crash in unity about a key being added to a dictionary twice which completely corrupts the animation controller, forcing me to restore it from a previous version.