The Light Attribute Node is used to specify parameters that are not contained in the light shader. For instance, several light shaders can use shadow maps; the Light Attribute Node can be used to generate these shadow maps. When there are no Light Attribute Node attached to a light, 3Delight for Maya will do its best to extract relevant parameters from the Maya light node.
Light Attribute Node – created empty
Light Attribute Nodes are created empty; it contains no attributes at all. It is an empty container where one can add just the relevant attributes. Attributes can be added and removed using Add / Remove Attributes button, which brings up The Add / Remove Attributes Window. Right-click on the Add / Remove Attributes button instead offers the same functionality through popup menus, which are more convenient when only one attribute or attribute group needs to be added or removed.