Copying Action From One armature to Another armature

Question

I am a beginner in blender.

I have 2 Armatures. They have different bone structures/names.

Armature A does some action for 200 frames, Armature B does some action for 80 frames.

I would like to add the action from Armature B to Armature A. I tried to use NLA editor, push the action from B to A, but it didn't work. I think somehow i need map each bone from Armature B to Armature A.(I couln't find a way to rename bones)

I searched for every related tutorial but i couldn't find how to map. All i can find was people joining actions using NLA editor, adding action strip.

After that i tried copying keyframes from Armature B to A, but i couldn't find a way to do it in neither dope sheet nor action editor.

I am not afraid to do lots of menial work (like renaming all of the bones) or using python scripts(i am comfortable with coding with python). But i couldn't find a way to do it.

Any detail will be appreciated as i am a newbie in blender.

Thank you in advance.

Answer 1

An object can have only one active action, this is the action that receives new keyframes when you keyframe a value. The same action can be assigned to multiple objects. The dopesheet has several modes which includes action editor which can be used to edit or create, delete and assign actions to an object. The NLA editor can be used to have multiple actions affect the same object and also has the ability to repeat, ret-ime and offset an action over time.

An action is a collection of fcurves that contains keyframed values for an objects property/s. Each fcurve contains a data path that specifies the property that the keyframes effect. While the dopesheet can adjust the timing, the graph editor is used to edit other details of fcurves, including the interpolation mode of the curve.

For an action to be usable on multiple objects, they need to have the same data path for property names, for things like location and rotation that simply applies to every object. For an armature the "data path" recorded for each keyframe includes the bone name, so to use an action on multiple armatures they need to have matching bone names. The keyframes in an action will animate the bones with matching names the same in each armature.