Blends two of three animations additively inside of an [AnimationNodeBlendTree]. A resource to add to an [AnimationNodeBlendTree]. Blends two animations together additively out of three based on a value in the [code][-1.0, 1.0][/code] range. This node has three inputs: - The base animation to add to - A -add animation to blend with when the blend amount is in the [code][-1.0, 0.0][/code] range. - A +add animation to blend with when the blend amount is in the [code][0.0, 1.0][/code] range If [code]true[/code], sets the [code]optimization[/code] to [code]false[/code] when calling [method AnimationNode.blend_input], forcing the blended animations to update every frame.