<layers>

    <visual>

        <param name="opacity" type="anim">
            <style>outquad</style>

            <duration>0.4</duration>

            <keyframe at="0.0">1.0</keyframe>

            <keyframe at="0.5">0.0</keyframe>
            <keyframe at="1.0">1.0</keyframe>

        </param>

    </visual>

</layers>