The PlaneFeatureDefinitionType defines the plane feature nominal information that can be common to one or more plane features. There is no definition information for a plane feature beyond what is provided by the SurfaceFeatureDefinitionBaseType.
The id attribute is the QIF id of the feature, used for referencing.
Source
<xs:complexType name="PlaneFeatureDefinitionType"><xs:annotation><xs:documentation>The PlaneFeatureDefinitionType defines the plane feature nominal information that can be common to one or more plane features. There is no definition information for a plane feature beyond what is provided by the SurfaceFeatureDefinitionBaseType.</xs:documentation></xs:annotation><xs:complexContent><xs:extension base="SurfaceFeatureDefinitionBaseType"/></xs:complexContent></xs:complexType>