Additive animation – this is an animation, which is added to the existing character motion to give the secondary behavior. For example, if the character runs and we put an additive hit, then as result character is running and getting hit. The result of applying the additive animations from a mathematical point of view is very simple – transformation matrix multiplication, from a user point of view additive animation – is the additional animation layer.
The script gives the possibility to calculate the difference between several animations and write the result in a separate take. In other words, suppose we have the original base animation “A” (like Idle, stay, etc.) and we animate some secondary behavior on top layer, let’s call it “B”. As a result, we have animation “C”. So this script allows for the existence of “A” and “C”, to calculate the “B”. Such additive animation can be used to create derivative movements calculated by adding the difference to some another animation.