In general, all that is needed to represent a polygon is the number of corner points (bendpointsCount). The number of bendpoints determines the basic form of the polygon, from a triangle to a polygon with any number of sides.
<node id="Schutzkreis" valid="=isInstanceEO() and
isInstanceOf('Rohbau_Architektur.Ebenenkomponenten.Schutzkreis')">
<figurePolygon figure="com.mind8.graph2d.figure.container.Polygon">
<properties>
<property id="bendpointsCount">
<read value="4"/>
</property>
</properties>
</figurePolygon>
</node>
Result:
The number of bendpoints can be edited in the diagram, if the property bendpointsModifiable is inserted and set to true.
See also: