From Garry's Mod
Returns the delta movement and angles of a sequence of the entity's model.
The sequence start cycle. 0 is the start of the animation, 1 is the end.
The sequence end cycle. 0 is the start of the animation, 1 is the end. Values like 2, etc are allowed.
Whether the operation was successful
The delta vector of the animation, how much the model's origin point moved.
The delta angle of the animation.