Blends two animations additively inside of an [AnimationNodeBlendTree]. A resource to add to an [AnimationNodeBlendTree]. Blends two animations additively based on the amount value. If the amount is greater than [code]1.0[/code], the animation connected to "in" port is blended with the amplified animation connected to "add" port. If the amount is less than [code]0.0[/code], the animation connected to "in" port is blended with the inverted animation connected to "add" port. $DOCS_URL/tutorials/animation/animation_tree.html