Additive Animation
Layering motion on top of other animation
Also known as: Additive animation Unreal · Additive layer Unity · Additive pose · Layered animation · Breathing additive · Hit reaction additive
Definition
Additive animation stores the difference between a pose and a reference pose, and adds that difference on top of another animation instead of replacing it. This lets effects such as breathing, leaning into a turn, aiming up and down, flinching from a hit or a damaged limp be layered over locomotion without making a new clip for each combination. It reduces the number of animations, and works in Unreal Engine through additive settings, and in Unity through additive layers.
In production
Author the additive clip as an offset from a neutral reference pose, such as the first frame, and set the animation's additive type correctly in the engine. Keep the amounts small and test at different strengths, because additive animation on top of unusual poses can break the shape. It is most useful for aim offsets, leans, hit reactions and facial or finger variations.
Tools that use Additive Animation
See also
Animation Blending
Interpolate poses between clips
Blend Space and Blend Tree
Mixing animations by a parameter such as speed
Animation Montage
Unreal asset for playing action sequences from gameplay
Animation State Machine
Graph of animation states and transitions
Keyframes and Interpolation
Poses in time and how the computer fills in between
Animation Pops Between States
Sudden jumps when switching animations