Index for everything about Skeletal Animations

https://docs.unrealengine.com/4.27/en-US/AnimatingObjects/SkeletalMeshAnimation/

Animation Overview

Animation Tools

• Skeleton Editor: In this editor, you can create Skeletal Mesh Sockets to attach items to a Skeletal Mesh, preview Animation Curves and track the associated Animation Notifications (Notifies) associated with the Skeleton. It is in this editor where you can also set up your Animation Retargeting options and manage your retarget sources with the Retarget Manager.

• Skeletal Mesh Editor: This editor allows you to make changes to the polygonal mesh by setting up Materials for the Skeletal Mesh, adding clothing elements, setting up LODs and testing out any Morph Targets (used to create complex Vertex-Driven animation (useful for facial expressions)) applied to the mesh.

• Animation Editor: provides easy access to the various animation-centric assets available for a Skeletal Mesh. In the Animation Editor, you can preview playback of animation assets such as Animation Sequences, Blend Spaces, Animation Montages, make edits to animation assets, add and edit curves for Material Parameters or Morph Targets as well as define Animation Notifies (events that occur during designated points in an animation).

• Anim Blueprint Editor: where you specify the logic the drives your character's animations and can be accessed by opening any Animation Blueprint.

• Physics Asset Editor: is an integrated editor that is part of the Animation Editors in Unreal Engine 4. It is specifically designed to manipulate Physics Assets for Skeletal Meshes.

  https://docs.unrealengine.com/4.27/en-US/InteractiveExperiences/Physics/PhysicsAssetEditor/

  Skeleton Assets:

• Skeleton: hierarchy of bone locations and rotations, used to deform a Skeletal Mesh. In Unreal, Skeletons are abstracted from Skeletal Meshes in their own asset. This means that animations are applied to the Skeleton, rather than the Skeletal Mesh. By using the same Skeleton, multiple Skeletal Meshes can share animations!

(more precisely)

If your Skeletal Meshes share the same Skeleton asset (pending some basic rules are met), you can share animation data even if the hierarchy does not exactly match. The sharing of a Skeleton asset between Skeletal Meshes provides a way for you to share animations between characters or even entire Animation Blueprints used to define animation logic for a character!

(see the documentation’s page for details)

Things the Skeleton Asset is responsible for:

• Animation Retargeting - which allows the adjustment of animations for characters with different proportions.
• Creating and saving Sockets - which allows you to attach things to your characters.
• Storing Anim Notifies - which allow you to add effects to animations like footstep sounds, particle systems or even custom events that may trigger other code.