Transforming an entire animation to match the location of another

Question

I am making an animation of a tennis player, and I am trying to combine 2 animations: an idle state (the player stationary, bobbing up and down) and a hit, blending them together using the NLA.

The issue is that both animations face a slightly different way, and neither take place at the origin of the armature (as the figure moves around). Here is view of the figure showing the origin point (hit animation):

and here are the two armatures viewed from above, overlayed, to show way i mean about them facing different directions (with second, idle animation selected):

I want to be able to rotate and slightly move the idle animation so that it aligns with the hit, so that when they are blended the figure doesn't slide around or rotate. Is there a way of doing this, essentially applying a coherent transform to every bone in every keyframe of the animation, so that it can be applied to the same model? (This is what i mean in the NLA):

(I have tried moving the hip bone (the parent of the armature) and replacing its rotation and location through blending in the NLA, but this pins the animation in the middle and destroys the bobbing motion unfortunately)

Many thanks

Answer 1

Ok I have found a solution that may be helpful to to others (though I welcome any other solutions).

In order to position the animations to be blended together on the same model, with the complete animation cycle being IDLE -> HIT -> IDLE, I needed to key in the Delta Transform and Delta Rotation for each action.

First I made an 'idle-start' action from the idle action I had and manually changed the Delta transform & rotation to align it with the first frame of the hit animation, by adjusting in the Object Properties tab, and made a single keyframe for each of these properties (press I > Delta Transform / Delta Rotation).

I then did the same with an 'idle-end' animation (copied from the original idle animation), and aligned this with the last frame of the 'hit' animation and keyed it.

Finally I went to the 'hit' action and reset these properties to 0 and keyed in there.

These three actions can then be pushed down to NLA strips and blended together using 'Combine' blend modes and fade in/out on the clips.

The final result should show the model seamlessly moving in place, but the origin point will animate as the actions/clips change.