The optional turned attribute shows if the referenced edge must be reversed from the original edge orientation.
Source
<xs:complexType name="EdgeOrientedType"><xs:annotation><xs:documentation>The EdgeOrientedType is a reference to an edge with a given orientation.</xs:documentation></xs:annotation><xs:complexContent><xs:extension base="ElementReferenceType"><xs:attribute name="turned" type="xs:boolean" default="0"><xs:annotation><xs:documentation>The optional turned attribute shows if the referenced edge must be reversed from the original edge orientation.</xs:documentation></xs:annotation></xs:attribute></xs:extension></xs:complexContent></xs:complexType>
<xs:attribute name="turned" type="xs:boolean" default="0"><xs:annotation><xs:documentation>The optional turned attribute shows if the referenced edge must be reversed from the original edge orientation.</xs:documentation></xs:annotation></xs:attribute>