The Basics of Organizing <Primitive Geometry>
All primitive objects in a SEDRIS transmittal must be part of some ‘organization’ (i.e., something has to aggregate them).
Every <Primitive Geometry> object must be a component of one or more <Union of Primitive Geometry> objects (see sheet 4 of the diagram).
<Union of Primitive Geometry> is the basic building block from which more complex aggregations are built. All geometric aggregations boil down to <Unions of Primitive Geometry>, <Geometry Model Instances>, and/or <Property Grid Hook Points>.