Question about animations

Hi there

I noticed there is a diffirence in reported memory size for a specific animation in the profiler at diffirent times. If I pull the animation out of the animated mesh ( FBX ) in the project editor and add animation events calling c# script events in a monobehaviour.

The original animation was 3 MB the animation with the logic and events is about 8mb.

Is the internal animation system used for animation clips created by pulling an animation clip out of an fbx not the same as the animation system used when FBX models are parsed and animtions are played in the editor?

Is FBX models parsed into another internal engine format rather than SkinnedMeshes, AnimationClips and the like.

I guess what im asking is if FBX stored using the Autodesk FBX SDK or stored using the assimp importer or just stored as internal structs of SkinnedMesh, AnimationClip, AnimationState and the like ?

Thanks in advance.