The published OCX Schema

Abstract element describing structure concept parts like columns, pillars, beams … Member has the following child elements:

Child	Namespace	Type	Use	Cardinality	Choice	Description
Description	ocx	xs:string	opt.	[0, 1]	False	Contains a description of the component its parent represents. The description is stored as a string. You can use this element for whatever purposes you require. This element can be used inside many OCX XML elements but is optional.
ExternalGeometryRef	ocx	ocx:ExternalGeometryRef_T	opt.	[0, 1]	False	The ExternalGeometryRef element is used to point to an external geometry representation of the parent entity (e.g. Plate, Stiffener, Bracket, Member).
LimitedBy	ocx	ocx:LimitedBy_T	opt.	[0, 1]	False	The references to limiting objects forming a closed contour of the parent element. It is not requiredthat the set of objects is ordered in the correct sequence.
PhysicalProperties	ocx	ocx:PhysicalProperties_T	req.	[1, 1]	False	Basic physical properties of structure objects (weight and centre of gravity). These properties are provided by the exporting application and can be used as a quality measure by the receiving application to ensure correctness of the import.

Member has the following attributes:

Attribute	Namespace	Type	Use	Description
GUIDRef	ocx	Restriction of type ocx:guid	req.	A globally Unique ID referring an entity in the sending application.
name	ocx	xs:string	opt.	An optional descriptive or display name.
id	ocx	xs:ID	req.	An identifier for an element unique within the scope of the XML file. Each id must be unique within a document. The attribute uses the standard XML 1.0 ID type as defined in the XML Schema specification. This attribute is required in many OCX XML elements and an application should generate them automatically.