Changing an animation is as easy as replacing the clip within the Animator Controller's state or blend tree. There is one additional step necessary in order to get the aim animation to work. When the character starts to aim, the controller needs to know when the aim animation is done playing so the item can then be used. This notification is sent through Animation Events. If we look at one of the aiming animations, such as the Assault Rifle Aim, we'll see that there is an animation event setup (indicated by the vertical white line near 1:00 on the timeline):
Opening this event we'll see:
These parameters let the controller know that the character is done aiming and is ready to use the item.
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