I'm trying to animate a horse along a path. What is the best practice to bake the path animation into the root bones position, without affecting other animations?
I added to my root bone the 'Follow Path' constraint and selected a nurbs path. If I try to manually insert the keyframes for my bones, with an active path constraint, those values aren't saved if I disable the constraint.
You can bake any bones path animation with Object > Animation > Bake Action.
Animations for bones are always in pose space (that's local space basically). If you would like them in "global" space, then you need to clear parents and not move with the armature object.
If you bake it only on the Root bone and then delete the Follow Path constraint on it, all other bones will stay unchanged.
One simple solution to animate a rotating root motion is to 'bend' the desired forward distance onto a fraction of a full circle.
For example:
My human character walks in one second 1.5 meters. Now I would like him to travel in sum 90° left or right from the starting position. That means he must travel 1.5 meters on the perimeter of a circle.
The question now is how big is the radius of the circle.
We know that the perimeter of a full circle is (1) p = 2*pi*r. Furthermore our desired distance d on the circle is only one quarter of the perimeter (2) d = p/4.
If we combine equation (1) and (2) and solve for r we get: r = (2 * d)/pi.
For our 1.5m walk animation we get r = 0.95m.
Now we only need to shift our 3d cursor 0.95m and rotate the root bone around this 3d cursor:
